CALIFORNIA AGRICULTURAL EXTENSION SERVICE CIRCULAR 113 DECEMBER, 1939 THE PRODUCTION OF STRAWBERRIES IN CALIFORNIA HAROLD E. THOMAS Cooperative Extension work in Agriculture and Home Economics, College of Agriculture, University of California, and United States Department of Agriculture cooperating. Distributed in furtherance of the Acts of Congress of May 8, and June 30, 1914. B. H. Crocheron, Director, California Agricultural Extension Service. THE COLLEGE OF AGRICULTURE UNIVERSITY OF CALIFORNIA BERKELEY, CALIFORNIA Digitized by the Internet Archive in 2011 with funding from University of California, Davis Libraries http://www.archive.org/details/productionofstra113thom CONTENTS Economic considerations 3 Importance of the crop 3 Production areas in the United States 4 Production areas in California .... 7 Production dates 9 Markets and crop movement 13 Nationalities concerned in pro- duction 21 Costs of production 22 Items of expense for the first year 23 Items of expense for the second vear 24 Yields'^ 24 Establishing the planting 26 Choice of a location 26 Soil types suitable for strawberry culture 27 Types of culture and methods used 28 Preparation of the land before planting 32 Time of planting 35 Number of plants required to set an acre 35 Treatment and storage of the plants before setting 36 Setting the plants 36 Cultivation and care the first year 38 kemoval of flower or fruit stems 38 Setting of runner plants 38 Irrigation the first year 39 Fertilization the first year .... 39 Careof theplantingthesecondyear 40 Harvesting 41 Fertilizing 44 Cultural and other practices in various districts 45 Central-coast district 46 Sacramento district 50 San Joaquin Valley district 51 Los Angeles district 52 Imperial Valley district 53 Other districts 55 Propagating and handling planting stock 55 Shasta area 57 Sacramento district 59 Turlock area 59 Fresno area 59 Los Angeles district 60 Oregon plants 60 Marketing and selling the straw- berry crop 60 Strawberry grades and standards . 61 PAGE Freezing storage of strawberries. ... 63 Varieties 64 Everbearing varieties 69 Diseases and insect pests of the strawberry 70 Leaf troubles 70 Leaf spot 70 Powdery mildew 70 Chlorosis 71 Leaf variegation, or gold disease 71 Red spider, or two-spotted mite 72 Strawberry aphid 72 Leaf beetle, or strawberry root- worm 73 Crown troubles 73 Crown rot 73 Strawberry dwarf, or crimp 74 Cyclamen mite 74 Strawberry crown moth, or crown borer 77 Strawberry root aphid 78 Spittle bug 78 Troubles affecting the general vigor of the plant 79 Yellows, or xanthosis 79 Crinkle 80 Verticillium wilt 80 Heavy grading of soil 81 Alkali and other excess salts .... 82 Nonadaptation of varieties 82 Root troubles 83 Brown-core root-rot, red stele, or phytophthora root-rot .... 83 Black-root 83 Oak-root fungus 85 Root-knot nematode 85 Weevils, or snout beetles 85 Strawberry rootworm, or leaf beetle 86 White grubs, or June beetles — 86 Wireworms 86 Garden centipede 87 Troubles affecting the fruit or blossom 87 Gray-mold rot 87 Other fruit rots 88 Powdery mildew 88 Western flower thrips 88 Cyclamen mite 88 Deformed berries, summer sterility, nubbins 88 California trends and outlook 90 Acknowledgments 92 THE PRODUCTION OF STRAWBERRIES IN CALIFORNIA HAEOLD E. THOMAS^ The strawberry is widely cultivated in home gardens and as a commer- cial enterprise in California (fig. 1) . The great adaptability of the plant is demonstrated by the fact that it is grown commercially both in the cool, foggy coastal regions and in the hot, dry, interior and southern valleys of the state, and at both high and low altitudes. Because of the wide range in soil types and climatic factors in the districts where this fruit is grown, no one type or method of culture can be recommended as suitable for the whole state. Each district has worked out its own meth- ods, perhaps copying what it could from other districts, but in many instances adopting a culture peculiar to its own conditions. In this cir- cular, the methods used in the care and handling of the crop in each of the several districts are described in order that the inexperienced grower may be guided by the accumulated experience of others in the same dis- trict and that the experienced grower may in some cases be able to im- prove his practice by knowledge of how certain problems have been met in other districts. ECONOMIC CONSIDERATIONS IMPORTANCE OF THE CROP The strawberry is the most important small-fruit crop in California. It is the first fruit to ripen in the spring. Because of this and the ex- tremely high dessert quality of the berry, it is consumed with avidity by the public during the spring months of each year. Many crops grown in California are sold extensively on eastern mar- kets, but strawberries differ in that the major portion of the crop is con- sumed within the state. Several hundred cars, however, are shipped from the state each year into markets where local berries are unavailable at certain seasons. In fact, with the exception of limited amounts produced by everbearing varieties for local markets, California is the sole commer- cial source within the United States of fresh, shipping strawberries from about July 15 to November 15, and during this period supplies the limited summer and fall demand for this commodity on the leading eastern markets. In no other state in the Union is the strawberry pro- duced and offered on the principal markets of the state every month of the year, as is possible in California. Because of the more or less con- tinual bearing habit of the strawberry in the central-coast district, yields 1 Associate Plant Pathologist in the Experiment Station. [3] 4 California Agricultural Extension Service [Cir. 113 per acre there are extremely high and cause a high state average yield. For the past several years (table 1), the commercial acreage of straw- berries in California has constituted only 2 to 3 per cent of the United States total, but because of the high yields, the crop has amounted to from 6 to 7 per cent of the total United States production. The value of the strawberry crop in the state is below that of pears, apples, apricots, peaches, grapes, and citrus, but exceeds that of plums, figs, olives, cherries, dates, avocados, and bush fruits. During the years of low prices, the reduction in value of the strawberry crop was much less than for most other fruits grown within the state. This could be explained partially by the lack of competition of the strawberry with other fruits because of the earliness of the season at which it ripens ; and partially by the fact that most of the crop was normally consumed within the state, and a large surplus did not exist from curtailment of consumption in the East, as was the case with the fruits principally dis- posed of on the eastern market. The estimated value of the crop in Cali- fornia has normally been between 2 and 3 million dollars annually (table 2). PRODUCTION AREAS IN THE UNITED STATES According to official data given in table 1, thirty states in the Union produce strawberries on a commercial scale. The largest centers of pro- duction are in the southern states, where early berries are produced and shipped to northern markets. The season starts in Florida in December and slowly moves northward, ending at the Canadian line in late June or early July, except for the summer production along the central Cali- fornia coast and from scattered everbearers. The division of the states into early, second-early, intermediate, and late groupings, as indicated in the table, gives a fair idea of the season at which each state produces its crop. The southern part of California is listed with the second-early states and the remainder of the state with the intermediate group. Although production in the central-coast dis- trict of California continues until late fall, only the period of peak pro- duction is considered in the table grouping. The acreage, production, and average price received per crate by the producer are given for the five-year average 1927-1931, which was a period of high prices, and for the two years 1936 and 1937, when prices were lower. The total acreage has decreased some in recent years over the earlier average, principally as the result of large decreases in Louisi- ana, Arkansas, and Missouri. The greatest reduction in prices has oc- curred in the early group. Large increases in acreage and production have occurred in the late group, particularly Michigan, Oregon, and Washington. Note that the crate sizes in tables 1 and 2 are different. TABLE 1 Acreage, Production", and Price per Crate Received by Farmers for Commercial Strawberry Crop; Average 1927-1931, Annual 1936 and 1937 Acreage Production Price per crate* Group and state Average 1927- 1931 1936 1937 Average 1927- 1931 1936 1937 Average 1927- 1931 1936 1937 Early (Dec-Feb.): Alabama acres 5,290 6.620 23,570 1,060 1,910 acres 2,700 8,900 14,800 500 2,400 acres 2,900 8,800 17,600 400 2,150 1,000 crates* 378 464 1,315 66 108 2,331 1.000 crates* 184 481 1,243 22 156 2,086 1,000 crates* 197 572 1,443 28 148 2,388 dollars 3.16 6.62 5.21 3.57 4.71 5.05 dollars 2.55 4.10 4.00 2.65 3.60 3.85 dollars 3.25 Florida. . 4 80 Louisiana 3.50 Mississippi 2.75 Texas 3 75 Total or average 38,450 29,300 31,850 3.80 Second-early (Mar-Apr.): Arkansas California (southern district) .... 16,980 1,610 300 6,200 360 14,940 8,360 12,400 1.550 820 8.800 560 15.600 6,100 7,400 1,650 600 9,200 600 14,200 7,000 40,650 778 342 16 662 27 894 675 3.394 496 232 41 519 38 437 427 2,190 259 297 36 644 45 923 630 2,834 2.76 4.37 2.83 3.08 3.08 2.51 2.73 2.91 2.30 2.85 3.00 2.80 2.70 2.15 2.90 2.58 2.75 2 90 Georgia 2.75 North Carolina 2.60 South Carolina 2.50 Tennessee 2.30 Virginia 2 25 Total or average 48,750 45,830 2.47 Intermediate (Apr.-May) : CaUfornia (other)t Delaware . . 2,250 3,930 4,420 920 6.230 9,180 20,530 4,820 1.4901: 3,150 5,200 5,600 800 8.200 7,500 8,600 3,400 600 3,000 5,200 5,400 900 6,700 7,700 4,500 4,000 200 37,600 415 323 216 52 356 663 885 392 48t 3,341 441 182 252 40 189 338 301 187 15 1,945 540 338 216 36 275 616 135 380 6 2,542 3.94 2.53 2.91 3.07 3.38 2.57 3.27 2.80 2. 79 J 3.02 2.60 2.75 2.75 2.40 3.05 2.50 3.35 2.65 2.50 2.78 2.95 2 40 Illinois 3.50 Kansas. 3 80 Kentucky 3.00 Maryland 2.20 Missouri 3.75 New Jersey 2.45 Oklahoma 4.00 Total or average.... 53,470 43,050 2.73 Late (May-June) : Indiana 1,550 2,660 5.180 4,470 3.840 9,650 2,980 1,450 7,970 2,830 2,700 600 11,000 3,600 4,000 13.600 4.400 1,100 10,000 2,100 2,600 600 10,500 3,500 4,100 14,000 4,800 1,400 10,000 2,400 102 170 372 427 233 666 268 99 566 190 3,093 135 30 770 252 240 1,142 286 55 800 94 3,804 182 33 945 280 328 1,050 480 91 900 168 4,457 3.03 3.93 3.70 3.93 3.73 2.97 3.32 2.76 3.28 3.89 3.44 3.40 2.75 2.90 3.30 2.85 1.95 2.75 1.40 2.15 2.50 2.45 3.30 3.75 Michigan 2.55 New York 3.45 Ohio 2.75 3.35 Pennsylvania 2.25 Utah 3.00 Washington 3.00 2.70 Total or average. . . . 42,580 53,100 53,900 2.91 Grand total or average. , . 183,260 171.280 164,000 12,158 10,025 12.221 3.48 2.84 2.94 * 24-quart crates containing approximately 36 pounds. t Includes April- December production. X Short-time average. Sources of data: 1927-1931: United States Department of Agriculture. Yearbook of agriculture 1934: 545. 1934. 1936 and 1937: United States Department of Agriculture. Agricultural statistics 1938: 231. 1938. California Agricultural Extension Service [Cir. 113 TABLE 2 Acreage, Production, and Farm Value of Commercial Strawberry Crop in Northern and Southern Districts of California, 1925 to 1938 Year District iicreage Yield per acre Production Value per crate* Total farm value acres 1,150 2,020 crates* 732 836 1,000 crates* 844 1.688 dollars 1.14 1.37 dollars 961,000 2.323,000 820 2.090 672 696 552 1,456 1.08 1.20 597,000 1,749.000 1,620 2,130 892 716 1,444 1,524 1.44 1.36 2,079,000 2,072,000 1,600 2,150 868 692 1,388 1,488 1.02 0.90 1,414,000 1.339,000 1,280 2,280 833 572 1.066 1,304 1.08 0.96 1.151.000 1.252,000 1,900 2,600 800 940 1,520 2.352 0.99 0.94 1.501,000 2,205,000 1,800 2,650 780 780 1,404 2,068 0.95 0.87 1,334,000 1.810,000 1.600 2,900 840 840 1,344 2,436 0.61 0.58 823.000 1,401,000 1,700 3,000 840 840 1,428 2,520 0.65 0.59 928,000 1,480,000 1,650 3,150 700 840 1,156 2,648 0.55 0.55 636.000 1.456,000 1,600 3.200 740 680 1,184 2,176 0.65 0.60 770.000 1,306.000 1,550 3,150 600 560 928 1.764 0.71 0.65 661,000 1,147,000 1,650 3,000 720 720 1.188 2,160 0.72 0.74 861.000 1,593.000 1,800 3.230 700 640 1,260 2,068 0.77 0.70 976,000 1,448.000 1925 1926 1927 1928 1929 1930 1931 1932 1933 1934 1935 1936 1937 1938 Southernf. Northernf. Southern . . Northern.. Southern . Northern. Southern. Northern. Southern. Northern . Southern. Northern . Southern . Northern . Southern . Northern . Southern . Northern . Southern. Northern. Southern . Northern . Southern. Northern . Southern. Northern . Southern. Northern . * Crates of 12 pint baskets — not the same as table 1. t Southern district includes Los Angeles. Orange, Riverside, San Bernardino, Imperial, San Diego, San Luis Obispo, and Santa Barbara counties; northern district includes all counties north of the San Luis Obispo-San Bernardino County line. Source of data: California Crop Reporting Service. Summaries of vegetable acreages. Annual issues. (Mimeo.) The Production of Strawberries in California 7 PRODUCTION AREAS IN CALIFORNIA Before 1920, the important strawberry-producing areas in California were within easy reach of large cities and supplied these communities with fresh berries ; very little attempt was made to ship the fruit any appreciable distance. With the advent of motor transportation and bet- Fig. 1. — Distribution of strawberry acreage in California in 1934. Each dot represents approximately 10 acres. (Data from : United States Department of Commerce Bureau of the Census. United States Census of Agriculture, 1935. 1936.) ter rail facilities, the areas of heavy production have changed consid- erably (fig. 1). New areas have recently developed that must ship their products upwards of 200 miles to markets within the state or several hundred miles to markets outside the state. There is no longer any necessity of being within easy reach of a large city where the entire crop must be consumed locally; it is only important that trucking or rail facilities be available. On the basis of geographical divisions and climatic differences, the commercial strawberry acreage in California may be roughly divided into five districts — central coast, Sacramento County, San Joaquin Val- 8 California Agricultural Extension Service [CJir. 113 ley, Los Angeles, and other southern areas, as indicated in table 3, which gives the estimated acreages by districts and counties for the past six years. Minor shifts have occurred in some counties but often have been TABLE 3 Strawberry Acreage in California by Districts and Counties, 1933-1938 District and county 1933 1934 1935 1936 1937 1938 Central coast: Alameda 150 20 200 20 380 380 50 130 20 200 20 370 410 40 150 40 230 10 350 400 40 150 40 200 10 300 450 40 130 40 100 10 170 400 70 180 Contra Costa 30 Monterey 70 San Mateo 10 Santa Clara . 200 Santa Cruz 450 Sonoma . 70 Total... 1.200 1,190 1,220 1,190 920 1,010 Sacramento : 1,000 1,100 1,100 1,100 1.150 1,350 San Joaquin Valley: Fresno 400 50 200 50 100 400 50 250 60 100 400 50 220 60 150 450 40 200 40 130 500 30 250 50 100 420 40 San Joaquin 250 60 Tulare 100 Total 800 860 880 860 930 870 Los Angeles: 700 800 50 30 800 700 50 20 900 510 50 20 1,000 340 50 20 1,100 300 60 30 1 200- Orange. . 300 50 San Bernardino 30 Total ... 1.580 1,570 1,480 1,410 1,480 1,580 Other southern areas: Imperial 20 40 60 10 50 20 10 100 10 10 120 10 10 150 10 10 San Diego 200 San Luis Obispo 10 Total 120 80 120 140 170 220 State total 4,700 4,800 4,800 4,700 4,650 5,030 Source of data: California Crop Reporting Service. Summaries of vegetable acreages. Annual issues. (Mimeo.) compensated for in adjoining counties, so that the district acreages have often remained fairly constant (table 4). Where fluctuations have oc- curred in districts, the percentage of the total state acreage has not often been materially changed. In the central-coast district, the acreage de- creased slightly over 20 per cent in 1937 from the previous four-year The Production of Strawberries in California 9 average but regained a portion of the loss in 1938. A gradual increase has occurred in the Sacramento district. PEODUCTION DATES Unloads on the Los Angeles and San Francisco markets by district of origin (tables 5, 6, 7) give an accurate indication of the producing dates of these districts. Seasonal variations in climate produce marked changes in the maturing date of the crop in a given district. Infrequently, shifts of a month or so are noted. Although not entirel}^ accounted for in the unloads in tables 5, 6, and TABLE 4 Strawberry Acreage in California by Districts, 1928-1938: Total for District AND Percentage of State Total State Central Coast Sacramento San Joaquin Valley Los Angeles Other southern areas Year total Total Percent Total Per cent Total Percent Total Percent Total Per cent 1938 5,030 1.010 20.1 1,350 26.8 870 17.3 1,580 31.4 220 4.4 1937 4,650 920 19.8 1,150 24.7 930 20.0 1,480 31.8 170 3.7 1936 4,700 1,190 25.3 1,100 23.4 860 18.3 1,410 30.0 140 3.0 1935 4,800 1,220 25.4 1,100 22.9 880 18.3 1,480 30.8 120 2.5 1934 4,800 1,190 24.8 1,100 22.9 860 17.9 1,570 32.7 80 1.7 1933 4,700 1,200 25.5 1,000 21.3 800 17.0 1,580 33.6 120 2.5 1932 4,500 1,330 29.6 900 20.0 670 14.9 1,490 33.1 110 2.4 1931 4,450 1,270 28.5 770 17.3 610 13.7 1,640 36.8 160 3.6 1930 4,400 1,230 27.9 700 15.9 570 12.9 1,720 39.1 180 4.1 1929 4,100 1,170 28.5 700 17.1 630 15.4 1,380 33.6 220 5.4 1928 4,250 1,250 29.4 620 14.6 480 11.3 1,660 39.1 240 5.6 Source of data: California Crop Reporting Service. Summaries of vegetable acreages. Annual issues. (Mimeo.) 7, Imperial Valley produces the first berries of the season, with ship- ments usually starting in late January or early February, extending through March and into early April ; a second crop matures in May. Los Angeles follows Imperial, with a few berries reaching the market in January and February of some years, but with the main portion of the crop starting in March, reaching a peak in April, and ending in May. The second crop matures in June and July. The San Joaquin Valley follows the Los Angeles district in the spring movement of berries by a period of 10 days to 2 weeks ; normally the Sacramento district is a week later than the San Joaquin. Shipments from these interior-valley districts extend to July or August, when the small second crop normally ends. Reasonably accurate dates for the opening and closing of the season in these districts during the five-year period 1934-1938 can be had by observing the unload dates on the San Francisco market (table 6). 10 California Agricultural Extension Service [Cir. 113 TABLE 5 Unloads of Strawbeeries at Los Angeles by District of Origin and Months, 1934-1938 (In carlot equivalents) Origin Jan. Feb. Mar, Apr, May June July Aug. Sep. Oct. Nov. Dec. Total 1934 California freight California carlot express California express l.c.I Truck: Sacramento Valley San Joaquin Valley Monterey-Santa Cruz . . . . San Luis Obispo-Santa Barbara San Diego County Los Angeles local district. Total 126 126 1 53 3 17 4 7 2 212 7 1 137 210 2 2 5 1 173 193 77 23 1935 California express l.c.I Florida express Truck: Sacramento Valley San Joaquin Valley Monterey-Santa Cruz . . . . San Luis Obispo-Santa Barbara San Diego County Los Angeles local district. Total. 25 7 160 167 324 1 3 1 162 199 102 24 1936 California carlot express California express l.c.I Truck: Sacramento Valley . . * ♦ 48 48 3 4 2 2 212 223 8 25 6 5 * 119 163 5 24 2 * 143 174 24 30 54 11 1 12 13 ♦ 13 7 7 4 4 3 3 16 115 10 San Joaquin Valley 7 Monterey-Santa Cruz San Luis Obispo-Santa Barbara « San Diego County * Coachella Valley. * Imperial Valley ♦ Los Angeles local district . . . Total 554 702 * Less than carlot quantity. The Production of Strawberries in California TABLE ^—Continued 11 Origin Jan. Feb. Mar. Apr. May June July Aug. Sep. Oct. Nov. Dec. Total 1937 California express l.c.l Truck: Sacramento Valley San Joaquin Valley Monterey-Santa Cruz . . . San Luis Obispo-Santa Barbara San Diego County Imperial Valley Los Angeles local district Total California express l.c.l California carlot express. . . Truck: Sacramento Valley San Joaquin Valley Monterey-Santa Cruz . . . San Luis Obispo- Santa Barbara San Diego County Imperial Valley Los Angeles local district Total 11 1 278 290 42 16 11 1 255 325 38 16 17 10 10 99 1 623 766 1938 31 223 231 106 48 12 166 245 99 25 47 33 625 900 * Less than carlot quantity. Source of data: Federal-State Market News Service. Monthly and annual unload summary. Fruits and vege- tables. Los Angeles. Monthly and annual issues. (Mimeo.) The central-coast district begins shipping strawberries at about the same time as the Sacramento Valley. Unlike other districts, the central coast produces continuously until late fall. Peaks are reached as the more or less definite crops mature. The production for the year 1935 is represented graphically in figure 2. The peak of production occurred in late May, then receded rather rapidly until the middle of June, at which time the curve flattened out somewhat and continued with minor waves for the remainder of the season. Production decreases and finally ceases with the advent of cold weather in the very late fall, but usually berries are shipped to the larger markets of the state until Thanksgiving or later, and occasionally a few until Christmas. 12 California Agricultural Extension Service [Cir. ii3 TABLE 6 Unloads of Strawberries at San Francisco by District of Origin and Months. 1934-1938 (In carlot equivalents) Origin Jan. Feb. Mar. Apr. May June July Aug. Sep. Oct. Nov. Dec. Total 1934 California express l.c.l Truck: Sacramento Valley San Joaquin Valley San Francisco Bay district . Monterey-Santa Cruz San Luis Obispo-Santa Barbara Total. 130 112 68 42 78 41 162 129 1 419 1935 California express l.c.l Oregon express Truck: Sacramento Valley San Joaquin Valley San Francisco Bay district . Monterey-Santa Cruz San Luis Obispo-Santa Barbara Los Angeles district Total 167 52 27 10 1 30 37 139 160 377 California express l.c.l Washington carlot express . . . Truck: Sacramento Valley San Joaquin Valley San Francisco Bay district . Monterey-Santa Cruz San Luis Obispo-Santa Barbara Imperial Valley Los Angeles district Total. * * 2 5 1 * 1 * 4 11 17 12 5 1 1 « 11 15 5 1 * 20 29 15 7 4 3 1 ♦ ♦ * * 16 38 46 20 8 13 6 3 3 * * • * * * * * 2 56 94 83 40 18 17 8 3 3 51 32 79 153 324 Less than carlot quantity. The Production of Strawberries in California TABLE 6— Continued 13 Origin Jan. Feb. Mar. Apr. May June July Aug. Sep. Oct. Nov. Dec. Total 1937 California express l.c.l Truck: Sacramento Valley San Joaquin Valley San Francisco Bay district Monterey-Santa Cruz San Luis Obispo-Santa Barbara Imperial Valley Los Angeles district Total California express l.c.l Truck: Sacramento Valley San Joaquin Valley San Francisco Bay district Monterey-Santa Cruz Imperial Valley Los Angeles district Total 27 153 41 18 22 77 136 282 1938 17 115 35 24 152 309 * Less than carlot quantity. Source of data: Federal-State Market News Service. Monthly and annual unload summary. Fruits and vege- tables. Los Angeles. Monthly and annual issues. (Mimeo.) MARKETS AND CROP MOVEMENT The fresh-fruit markets of this and other states are the only important outlets for strav^berries grown in California. The fev^^ berries manufac- tured into preserves account for a very minor portion of the total crop. During the years before low prices, when the preserved product com- manded a fair price in comparison to the fresh-market return, surplus fruit at the peaks of production often went to the preservers. For the past few years, most of the berries used for preserving on the coast have been supplied by the Pacific Northwest, which produces them more cheaply than California. Consequently the preserving market is, as a rule, not profitable for growers within the state. Shipments of strawberries by express and freight to the larger mar- kets in adjoining western states relieve the pressure on California mar- kets and result in a more orderly marketing and higher returns than would otherwise be possible. The origin and extent of shipments out of 14 California Agricultural Extension Service [Cir. 113 the state and the market destination for the five-year period from 1933 to 1937, may be found in tables 8, 9, and 10; and in table 11 are given, for the same period, the dates for the beginning and the end of the ship- ping season from each district. Portland, Seattle, Spokane, Vancouver, Salt Lake City, Butte, and Denver are the principal cities shipped to in the spring of the year. While there are a few less than carlot (l.c.l.) shipments expressed to TABLE 7 Express L.C.L. Unloads of Strawberries on Los Angeles Market by Origin^ 1934-1936t (In carlot equivalents) Origi Total Apr. May June July Aug. Sept. Oct. Nov. Dec 1934 12 12 13 I t 21 3 130 10 5 1 19 5 200 31 Fresno Sunnyvale. San Jose . . . . Gilroy Watsonville Santa Cruz. Salinas Total... Fresno Sunnyvale. San Jose Gilroy Watsonville Santa Cruz. Salinas Total . . . Fresno Sunnyvale. San Jose. . . . Gilroy Watsonville Salinas Total... 3 3 3 1 t t t 6 3 3 2 1 43 26 10 10 3 1 1 t 2 1 55 34 16 13 4 1935 6 6 2 1 1 t t t t 1 i 3 t t 2 t t 101 24 17 22 15 12 6 4 2 1 19 8 4 6 1 t t 134 41 22 29 18 12 6 5 1936 5 2 3 t t t t t 2 1 t t 1 t t t 97 2 19 23 22 10 14 7 9 3 3 2 t 1 t 113 4 26 26 24 11 15 7 t * San Luis Obispo-Santa Barbara district not included. t No shipments reported during January, February, or March from shipping points listed, t Less than carlot quantity. Source of data: Compiled from data furnished by Railway Express Agency. A slight discrepancy exists between figures in this table and those in table 5. The Production of Strawberries in California 15 various points, the markets which are listed in table 8 are undoubtedly all those of any significance, except in a few instances, where apprecia- ble quantities of berries are redistributed by local express or truck from the large markets receiving carlot shipments to smaller towns in the vicinity. By far the greater part of the early-spring shipments originate in the vicinity of Sacramento. The Sacramento district has an advantage over other districts in its proximity to the markets of the Northwest, which results in slightly lower express and freight rates ; as a consequence it is the principal dis- trict in the state that ships to the Northwest (tables 9 and 10). Districts of the state other than Sacramento supply the California markets and ship outside the state only at the peak of the season during years when a large crop is harvested and a surplus exists that cannot be disposed of advantageously on local or state markets. If the surplus is not moved into markets outside the state but is offered on local markets, the price to the producer usually drops far below the cost of production and may stay low for the remainder of the season. The central-coast district makes very few interstate shipments in the spring except to Denver but, as previously mentioned, finds an outlet for a portion of the summer and fall crops in the large eastern markets of the United States. The movement starts as the crop ends in the eastern states and continues until near the middle of November, when berries from Florida begin to compete. The amounts indicated in table 8 do not represent the actual quantity shipped from the central-coast district, since only cars that are wholly or predominantly filled with strawberries are recorded: many mixed cars of raspberries and strawberries are shipped each season but are listed in the table only if the cars consist of more than half strawberries. Total eastern shipments from this district, as given by the Central California Berry Growers' Association, are as follows : Number of Carlot Year crates equivalents 1932 68,580 46 1933 125,308 84 1934 114,866 77 1935 113,061 75 1936 99,158 66 1937 58,936 39 Within the state, the Los Angeles metropolitan area constitutes by far the largest market outlet. San Francisco is next in importance. The combined consumption of these two cities has, during the five years 1933 to 1937, varied from 50 per cent to 70 per cent of the estimated production of the state. According to the 1930 Census, about one-third 16 California Agricultural Extension Service [CfiR- us CO ■ c^ (M • • (M (M CO cq rt •* c<) <>» OO »-( t^ rH o c3 <1> 03 1 i h:i m w ^ M i^ p. -5 a> a* (U a ;|pq(2H ocpiiwdm > iM is o .2 _o _ > bj O .2 Q £ 5 H 03 X CO 01 a.ti ■^3 CO OS I! a>. n 0) ^ a w a 'o £§ ^ o-^ •s 0.2 pci 03 2 -3 £ S3 as 3-0 "o h « 0) S-i 3 CQ 02 18 California Agricultural Extension Service [Cir. 113 of the state population is to be found in the two cities. If the figures on consumption are accurate, it indicates that the per capita consumption in large cities is much higher than in the smaller towns and rural com- munities. It seems more likely, however, that the difference is partly made up from dooryard plots and miscellaneous small acreages that do not enter into the estimated state output. The unloads on the Los Angeles and San Francisco markets by dis- trict of origin (tables 5 and 6), coupled with a breakdown of the less- than-carlot express shipments for the Los Angeles market (table 7), TABLE 9 Freight Interstate Carlot Shipments of Strawberries from the Sacramento District by Destination, 1933-1937 Destination Oregon : mostly Portland Washington: Seattle, Spokane, Tacoina. Canada: Vancouver Idaho: Boise, Pocatello Utah: Salt Lake City Illinois : Chicago Total. 1933 223 1934 221 1935 190 1936 119 1937 12 6 4 26 Sources of data: Southern Pacific Co. and the Western Pacific Railroad Co. give a reasonably accurate record of the origin and crop movement within the state. Local production or neighboring areas for the most part take care of the demands in the other cities and towns of the state with the exception of the Oakland and adjoining East Bay cities, where a fair quantity of berries, varying from one-third to one-half of their total consumption, comes from districts in the interior valleys. The Los An- geles strawberry district produces insufficient berries to supply the demand in that market, and fruit must be moved in from other districts of the state. However, at the peak of the crop in some years there may be an oversupply and a few cars are shipped elsewhere. The movement into the market, more than half of which is express less-than-carlot shipments from the Watsonville district (table 7), is not the result of inadequate facilities within the district to supply the demand, but rather the result of a lack of a suitable variety or varieties that produce a crop between the first and second crops of the favorite Klondike variety, and during the late summer and fall months. Another factor partially responsible in the past for the movement of strawberries into the Los Angeles market from other districts of the state, is the superior dessert quality of some of the varieties of berries produced in the other districts. The Production op Strawberries in California 19 The markets upon which the crop from the central-coast district is sold are the most varied of any district in the state. Figure 2 illustrates for the year 1935 the total production and disposition of the crop by TABLE 10 Combined Express and Freight Interstate Carlot Shipments of Strawberries FROM THE Sacramento District by Destination, 1933-1937 State of destination Oregon Washington Canada — British Columbia Idaho Montana Wyoming Utah Colorado Arizona New Mexico Texas Nebraska North Dakota Kansas Illinois Total 1933 1934 1935 1936 1937 100 129 3 12 1 60 1 92 112 9 9 16 43 5 306 288 279 263 89 141 4 9 15 4 40 9 2 2 11 1 327 Sources of data: Tables 8 and 9. weeks and gives an idea of the complexity of the crop movement for this district. Growers must keep themselves constantly informed concerning these markets if they are to receive highest returns. Although not neces- TABLE 11 Express Interstate Shipping Season of California Fresh Strawberries by District, 1933-1937 Sacramento Fresno Central coast Los Angeles Year Beginning End Beginning End Beginning End Beginning End 1933 1934 1935 1936 1937 April 24 April 11 April 30 April 15 April 25 June 10 May 10 June 11 June 11 June 1 April 24 April 2 May 1 April 15 April 21 May 25 April 25 May 22 April 29 May 13 May 12 June 28 May 10 April 27 May 11 November November November October August 4 17 16 17 10 April 9 March 25 April 16 April 15 April 19 May 3 April 5 April 29 April 22 April 26 Source of data: Railway Express Agency, San Francisco. sarily indicative of the prices received on local markets, figure 3 illus- trates graphically the appreciable fluctuations in the monthly averages of the net return per crate to the grower on interstate shipments for the 20 California Agricultural Extension Service [Cm. 113 j-*— ■ Tota/ production 1*— kSc/7 1 Francjsco \ Oakland \. '\ / V, '■■^\'Los AiKje/es \ V. \ \ ^---\ vxr \ ^•-^ •<^/^~' ''^■^iz:^Cannery ~^- — ■■■^:_I::-l,!Iz;iir.'~i:i^;-2^:^.- 6 13 20 27 4 II 18 25 I 8 15 22 29 6 13 20 27 3 lO 17 24 31 7 14 21 28 5 12 19 26 2 9 16 23 30 7 14 21 28 April May June July August September October November December Fig. 2. — Total production and disposition of strawberry crop grown in the central- coast district, by weeks, 1935. (Data from the Central California Berry Growers' Association.) The Production of Strawberries in California 21 six-year period 1932-1937, along with the yearly average return on such shipments. Since the volume at high prices is low, the true yearly aver- age for the crop is far under the average for the year based on monthly averages. NATIONALITIES CONCERNED IN PRODUCTION The commercial strawberry crop in California is handled largely by Japanese. Part of the plantings in the state are operated by white grow- ers who arrange with Japanese to take care of the plants and pick the 31 -M 36 32 3f 36 32 34 36 3« ^4 36 32 34 36 AUGUST SEPTLdBLR 0CTC8ER NOVEMBER DECtnBER 2 34 36 YEARLY AVtRAGL Fig. 3. — Average price received per crate by grower by month and by year on interstate strawberry shipments for the six-year period, 1932-1937, central-coast district. The asterisks indicate no shipments. (Data from the Central California Berry Growers' Association.) fruit. Usually the Japanese take complete care from the time of setting out until the planting is abandoned. Similar arrangements are often made between Japanese growers and their help. The operators arrange with the individual Japanese families to care for a designated number of acres, varying from 2% to 5 acres or more, according to the district where the planting is located and the size of the Japanese family. The family, consisting of a man and his wife and whatever children there may be old enough to work, is normally compelled during the peak of the picking season to hire extra help, which is usually either Japanese, Filipino, or Mexican. White help is seldom employed in this state except in mountain and out-of-the-way districts where Asiatic, Mexican, or other labor is not available. The Japanese are particularly well adapted to the work of caring for strawberries: they are able to maintain a squatting position for hours without any apparent physical fatigue; 22 California Agricultural Extension Service [Cm. 113 and this position is the one most convenient when working with a plant as close to the ground as the strawberry. COSTS OF PRODUCTION Few crops are as expensive to produce as the strawberry. The industry in California is highly developed and specialized, and great pains are taken to obtain the highest possible yield per acre. The question some- times arises whether the increased income from such a painstaking type of culture is sufficient to compensate adequately for the higher costs entailed. The system in use, however, has given very high returns and is being continued. The major portion of the cost of production on a given acreage is incurred the first year, and normally no income is de- rived from the planting during this year. In the past, the heavy first- year expense has been justified, or at least made economically feasible, because of the length of life or duration of the planting, which in nu- merous instances was six or seven years ; the high cost could be spread over a producing period of several years. But now because of lower prices and the reduced life of many plantings (frequently not over three years), the high initial cost absorbs so much of the total income that the industry is in general only moderately remunerative. Some of the reasons for the reduced longevity of strawberry plantings are known, and because of the nature of these modifying influences, there seems little likelihood that the situation can be immediately remedied. Estab- lished or potential districts largely free from these inimical influences have a real advantage over less-fortunate districts where they occur. The matter should be given careful consideration by the prospective grower because of its bearing on the profitableness of a planting ; it is extremely important in computing the cost of production and in de- ciding upon the practicability of any area for the production of straw- berries. The actual costs of production vary widely within the state accord- ing to the type of culture employed, the system of management, and to some degree the yield per acre. For instance, the costs per acre are highest, with the exception of Imperial Valley, in the central-coast dis- trict, where yields are also highest ; the higher costs in this latter district are in part attributable to higher yields and the resulting increased cost of harvesting, but in large part to the intensive type of culture. The lowest costs are found in the interior valleys, where of necessity pro- duction expenses are reduced in order to compete with districts that have higher annual yields ; a contributing factor in the lower costs of interior-valley plantings has been their greater longevity. As in all types of farming, the efficiency of the operator in the man- The Production of Strawberries in California 23 agement of the planting is an important item in the cost of producing strawberries. Unless proper attention is given such items as irrigation, cultivation, weed control, proper spacing of runner plants and proper time of setting them, disease and insect control, fertilization, proper picking, and care of the fruit when picked, the returns may be low and not meet the costs of production. The size of the planting as an item in the cost of production per acre probably has less influence with strawberries than with most other crops but cannot be passed by without consideration. A family unit can take care of 2% to 5 acres. Ordinarily the planting is made up of a series of these units, and because each unit is handled separately, the number involved is of minor importance in cost per acre when only the care of the planting is considered. The capital outlay, however, has more bear- ing upon the size. A small planting of 2 or 3 acres would not justify the purchase of the necessary equipment to level and prepare the land for planting, but in most districts, tools can be rented or the work hired done. The cost of developing adequate irrigation water if none is avail- able would be an item of appreciable importance in determining the size of the planting ; usually small plantings are not attempted unless water is at hand. Items of Expense for the First Year. — The specific items of expense are exceedingly variable from one district to another, and appreciably so even from one planting to another within a district. Prices have varied so greatly during the past ten years that any attempt to predict future costs is particularly hazardous. If a value is placed on all items of cost whether cash or noncash, the establishment of a strawberry planting may involve the following items of expense : Estimated cost per Item acre for 1939 Eent $ 10-$ 45 Grading and leveling 20- 45 Preparation of land for planting 5- 10 Plants 14- 85 Labor for setting out plants 15- 35 Flumes for irrigation water 0- 45 Cultivation and care of plants (including the setting of runners) 60-200 Water for irrigation 10- 30 Spraying and dusting 0- 10 Fertilizing 0- 20 Housing of workers 0- 35 Well, pump, motor, pipe, etc 0- 75 Interest and depreciation on investment and equipment. . 5- 50 Total expense, first year $139-$685 24 California Agricultural Extension Service [Cm. 113 The amounts for the items as listed above are rough estimates made by- growers, managers of associations, or others, in the several districts of the state. The Imperial Valley district, where a specialized and expen- sive culture is used, is not included in the above estimate. There is in all probability no commercial section in the state where strawberries can be produced over a period of years for the lower figure. Likewise, only in the central-coast district does the cost of production approach the higher amount ; in this district, during the years of high prices previous to 1930, growers often estimated the cost of bringing a planting into pro- duction to lie between $750 and $1,000 per acre. The actual outlay of expense for the first year may amount to well over the $685 per acre itemized above if it is necessary to bore a well or construct new buildings to house the help. In the figures given these costs have been prorated over a period of time corresponding to the estimated life of the planting. The other items are assumed to be entirely paid for the first year. Items of Expense for the Second Year. — The greater amount of the second-year cost is that concerned with the harvesting of the fruit and varies with the yield. In the following estimates for the second year, the figures for costs that vary with yield — picking, baskets and crates, and transportation charges — are based on average yields for low- and for high-producing districts. Estimated cost per Items acre for 1939 Rent $ 10-$ 45 Picking (18 cents per 12-basket crate) 135- 405 Care of planting 25- 75 Irrigation water 15- 50 Baskets and crates (8 cents per 12-basket crate) 60- 180 Transportation charges (including pickup truck) (7 cents per 12-basket crate) 50- 155 Spraying and dusting 0- 20 Fertilizing 0- 30 Housing of workers 0- 35 Well, pump, motor, pipe, etc 0- 75 Interest and depreciation on investment and equipment ... 5- 50 Total expense, second year $300-$l,120 YIELDS The highest yields found anywhere in the United States are obtained in the central-coast district of California, and the average yield for the state is higher than that for any other state in the Union. These high yields are largely the result of an intensive specialized culture and a peculiarly favorable climate. A record yield was made as early as 1915 in the Irvington area of Alameda County, where berries of the Banner The Production of Strawberries in California 25 variety were harvested at the rate of 36,000 pounds, or 18 tons per acre. This is equal to 4,000 of the 12-basket crates, or 48,000 pint baskets. Since that time, a few Nich Ohmer and Banner plantings have given yields approximating this figure, and recently plantings of the new Dorsett variety in the Watsonville-Salinas area have exceeded it and yielded well over 20 tons per acre. These yields are very exceptional ; the yearly average of all plantings of all ages for the coast district will be less than half these amounts. An estimate of the range in high, low, and average yields in 12-basket crates for this district for the second- and third-year crops and for the Banner and Nich Ohmer varieties follows : High yield Low yield Average yield Banner: Second-year plantings 3,200-3,800 1,000-1,600 2,000-3,000 Third-year plantings 1,800-2,400 800-1,000 1,200-1,600 Nich Ohmer: Second-year plantings 3,000-3,500 800-1,200 1,500-2,500 Third-year plantings 1,200-1,600 300- 600 800-1,000 These figures represent the expected for a well-taken-care-of planting and are much above the estimates for the northern and southern state average indicated in table 2, which include all kinds of plantings. The Los Angeles district is the next-highest-yielding district in Cali- fornia. The Klondike variety is used mostly, and estimates have placed the high, low, and average yields in 12-basket crates for the second and third years in this district about as follows : High yield Low yield Average yield Second-year plantings 3,000 1,000 1,800 Third-year plantings 2,400 800 1,400 These yields are very high for a variety that produces very little, if any, late summer or fall crop and indicate the tremendous load of fruit that the plants must mature in a relatively short time during the spring and early summer seasons. The Sacramento district, growing the Marshall-type plants, will pro- duce much less than is obtained in the coast district because there is little if any late summer or fall crop. In this district in the second-year plantings, a high yield estimate would be 1,600 crates (of 12 baskets each) , with 600 for a low yield and 1,000 as an average yield. The third year, the amounts are reduced to about one-half of the second-year yields. The estimate for the Fresno area is under that of Sacramento, with the high, low, and average yields for the second year approximating 1,000, 600, and 750 crates respectively. Third-year-planting yields would approximate those obtained in the Sacramento district. The 26 California Agricultural Extension Service [Cir. ii3 above estimates were made by growers, association managers, or others in the several districts of the state, of the variation in yields over a period of years. While the estimates are undoubtedly rough, they give some idea of the differences between districts. Ordinarily no fruit is allowed to develop on the plants during the first growing season. The yields are highest the second year in all districts of the state. Variable yields are obtained the third and succeeding years. In the central-coast district, the third-year crop may amount to less than one-half the crop of the previous year. In the Los Angeles district, it sometimes equals the second-year crop, but because the fruit is small, the return is much less. Yields are highly variable from season to season. Except for serious reductions in some seasons resulting from disease or insect injury, they are usually causally related to favorable or unfavorable weather condi- tions occurring at critical stages in the development of the strawberry crop. Thus rain often spoils a considerable portion of the crop if it occurs during the peak of the picking season and particularly if it causes a damp period for any extended length of time. Late spring frosts are sometimes responsible for a considerable reduction in yield of early fruit. An abnormally warm and dry winter may force blossoming ex- tremely early, retard foliage development, and mature the fruit with- out the production of sufficient leaf surface to take care of the re- quirements of the maturing berries ; the plant, with this excessive drain on its vitality, fails to produce as heavily as it otherwise would. Hot, dry winds in the interior valleys or excessive hot weather early in the season will reduce yields. ESTABLISHING THE PLANTING CHOICE OF A LOCATION From the discussion of climatic factors that affect yields, it is evident that in the choice of a location for a planting, weather conditions should be among the factors considered. Thus, because the strawberry is one of the earliest of fruits to blossom and because the blossoms and small fruits are easily killed if the temperatures drop much below freez- ing, localities or areas subject to spring frosts should be avoided when- ever possible. If the first bloom is frozen, more blossoms and fruit will usually develop later, but prices for this late crop may not be satisfac- tory. If rolling land is used, swales and low spots, into which cold air drains from the surrounding higher land, should not be planted to strawberries. Strawberries may, however, be grown in cold mountain areas provided snow or cold weather retards the starting of spring The Production op Strawberries in California 27 growth until late in the season. In these areas, the everbearing varieties, because of their very late spring habit of blooming, often succeed where other varieties fail. A warm southern exposure is helpful when early berries are desired. The fruit will often mature from a few days to a week earlier if the land faces the south rather than some other direction. Extremely windy areas, especially where the soil is sandy and where shifts by wind movement cause cutting and beating of the foliage and scarring of the fruit, are less desirable for strawberry production than areas where wind is not a factor. Extremely hot, dry weather during the period of fruit production is unfavorable and causes burning of the fruit with a resultant lower yield. Such weather is often a factor in the interior valleys but usually affects only the second crop, the first being harvested before such weather occurs. Strawberries require frequent irrigation under most California con- ditions, and in the location chosen for a planting there must be an ade- quate supply of water free of salts and alkali. The strawberry plant is particularly susceptible to injury from salts or alkali, hence it is a good practice to have the irrigation water tested for injurious elements be- fore establishing a planting. The University provides a free service for testing water, which is available to all who wish to make use of it. Of utmost importance in the consideration of the location is the previ- ous crop history of the land in question. Informed growers prefer old grain, pasture, or recently cleared orchard land, because they have learned by experience that land used for truck crops for any extended length of time usually is unsatisfactory for strawberry culture. In recent years, studies made by the author show that Verticillium wilt is an important limiting factor in such soils and that it is extremely hazard- ous to use land that has been previously cropped to tomatoes or potatoes. Even though eight or ten years may have elapsed since such crops have been grown, there is considerable likelihood that the fungus is still pres- ent in the soil. Most varieties of strawberries are very susceptible to the disease. The problem is discussed further in the section on diseases. Small quantities of strawberries can usually be disposed of locally. Larger amounts must be shipped, and then daily trucking or express facilities to the larger markets are necessary. SOIL TYPES SUITABLE FOR STRAWBERRY CULTURE Strawberries may be grown on almost any type of soil provided the surface is well drained, but the lighter types are usually selected for commercial production if a choice can be made. The ideal soil for straw- 28 California Agricultural. Extension Service [Cm. 113 berry culture is mellow, friable, well drained, non-crust-forming, and easily handled and stores a relatively large amount of water in a form available to plants. When the heavy adobe soils are used, it is often necessary to use a variety adapted to them if one is available for the dis- trict. The lighter sandy soils are more easily worked and handled and require less exacting care than the heavier types. They warm up earlier in the spring and consequently produce slightly earlier fruit. In lighter soils there is less danger of overirrigation, waterlogging, and running together. On the other hand, the heavy soils usually store a large amount of available moisture and require less frequent irrigation. Soils that naturally have high organic-matter content tend to have better physical qualities and are easier to handle; the latter is extremely important since so much of the work of caring for a strawberry planting is done by hand labor and small tools. Thorough drainage, particularly during the winter, is essential. Water should never be allowed to stand in a strawberry planting : if an excess collects in the furrows during periods of prolonged rainfall, ditches should be constructed to carry it off. Strawberries often do exceptionally well on soil considered extremely deficient for other crops, and frequently such land can be and is profit- ably utilized for strawberries, often without the addition of any ferti- lizer. On the other hand, it is generally unprofitable to use land con- taining alkali or excess salts : the strawberry is extremely sensitive and reacts unfavorably when these are present in any appreciable amount. Level land is preferred to rolling or sloping land for strawberry cul- ture because of the greater ease with which the beds are laid out and the planting taken care of. Irrigation water is more easily distributed on level land and a less expensive system of distribution is required. On rolling land it is usually necessary to plant on contours to prevent erosion and washing. TYPES OF CULTURE AND METHODS USED Practically all the berries grown commercially in the state are irri- gated, hence each district has adopted a method of culture that is to a large extent built around a type of irrigation practice and reasonably uniform for the district. The necessity for frequent application of water has led to the adoption of systems of irrigation that require a minimum of labor. These systems are so planned that they last the life of the plant- ing and require a minimum of attention. A makeshift system is seldom satisfactory in strawberry culture. Provision must be made at the time the planting is laid out for the type of irrigation and culture that is to be used. The plants are usually The Production of Strawberries in California 29 set on raised beds with irrigation furrows between the beds. In the few plantings where no irrigation or overhead sprinkling is practiced, a flat or level culture similar to that for other nonirrigated crops is used. In raised-bed culture, the width of the bed is dependent upon the extent to which the irrigation water will move laterally through the soil, and this factor often determines the method of spacing and grow- ing the plants. When it is necessary to use a very narrow bed, a "single- row" system of planting is followed in which the plants are set out in rig. 4. — Strawberry planting in Alameda County using the raised spaced-bed type of culture common in many sections of California. The slight change in di- rection of the rows indicates minor breaks in the level of the different beds. Water is distributed from a central point by wooden flume. Chests filled with strawberries and covered vdth canvas to prevent the sun from striking the fruit may be seen along the central roadway. one row, either at the distance desired when in production or, as is the usual custom, at a greater interval with the intervening space filled in with the runner plants developing from those originally set. If a slightly wider bed is used, a double-row system of planting may be employed in which two rows spaced 8 to 10 inches apart are set out on the surface of the bed. The spaced-row system (fig. 4) is normally used when beds are 18 inches or more in width. For this type of planting, the original plants are set 2 to 3 feet apart in rows 3 or 4 inches in from the edge on either side of the bed, and the intervening space is filled with runner plants in the summer and fall. These are spaced from 6 to 10 inches apart, according to the varietal characteristics of the plant, such as size and denseness of the crown. The runner plants are usually spaced by hand and held in place until the roots start by pushing the plant into loosened soil or pinning the runner down with a clod. Infrequently the runners are allowed to run and set at random ; they then form a matted bed and are later thinned out to the desired distance. This practice, 30 California Agricultural Extension Service [Cm. 113 however, is seldom satisfactory and not to be recommended, for most runners set in the furrow or fail to root on the top of the bed because of the dryness of the soil. . When flat culture is employed, the hill system of planting is some- times used in preference to the single-, double-, or spaced-row system. The plants are set out on the square and commonly spaced at an interval of 30 inches. No runners are allowed to root. In the Los Angeles district, the usual procedure is to set the plants in early spring, flat culture, and space them 3 feet apart in rows 4 feet apart. When these have developed sufficient runners, the land is ridged, Fig. 5. — Typical scene in the Los Angeles strawberry-growing district dur- ing the picking season. The truck is loaded with the 30-basket type of crate commonly used in that area for local shipments. On the right are crates of the 12-basket type nailed together with strips in lots of four for express shipment. (Courtesy of Walter Knott.) the beds formed, and runner plants set so as to give a spaced row with alternating furrows similar to the bed of other districts (fig. 5). In most districts, the experience of growers has led them to adopt the rather uniform practice of laying out strawberry beds on an essentially level grade. Several factors contribute to the efficiency of this method of culture. When water is run in a furrow possessing some fall, erosion usually results unless the volume is reduced to such a point that it takes a long time to obtain adequate lateral penetration. In instances where the method of allowing fall to the furrow is used, special methods of distributing the water to the furrows are necessary and, furthermore, some means of collecting and disposing of the runoff water at the end of the furrows must be devised. Although it obviates the necessity of extensive leveling, the method is not recommended and not feasible in most soils. The level-culture method with a satisfactory distributing system permits the uniform and expeditious application of water to the irrigation furrows. In fact, with the large head of water that often must be handled and the small number of beds to be irrigated — the re- sults of one day's picking — the level -bed method is the only feasible one. / The Production of Strawberries in Calif/Ornia 31 Leveling in more than one direction is obviously not necessary : as long as the furrow is level the water will distribute unif oriniy, and thus even steeply sloping land may be used. Contour planting is often resorted to on steep or rolling land where leveling in even one direction is im- Fig. 6. — Contour type of planting with raised spaced bed as used in the Wat- sonvUle area of the central-coast district. This method is commonly used on rolling or uneven land and obviates the necessity of moving much soil in pre- paring the land for planting. practical. By varying slightly the width of the raised bed, irregularities in the slope may be taken care of (fig. 6 A, B). On flat or moderately flat land, however, the usual method is to level in one direction so that the rows may run parallel. The direction of the grade may have to be changed (fig. 4) in order to obviate the moving of too much soil, both 32 Ca.lifornia Agricultural Extension Service [Cir. 113 from the standpoint of cost and from the fact that strawberry plants do very poorly if much over 3 inches of top soil is removed. The length of the furrow to plan for is dependent in part upon the type of soil : if the water penetrates the soil rapidly, it cannot be run a great distance without overirrigating one end of the row and under- irrigating the other end; if it penetrates slowly, longer furrows may be used. The contour and unevenness of the land will obviously affect Fig. 7. — Terrace method of growing strawberries and single-row method of planting. Irrigation water is brought to each level by a pipe or ditch. The method necessitates heavy cuts and fills, which ordinarily are undesirable in strawberry culture. the length of the furrow and may prevent long runs even though the soil might allow them. The actual length of the furrows used in Cali- fornia strawberry plantings, without including the extremes, varies from 100 to 400 feet, but in the major portion of the plantings using raised-bed level culture, the furrow length is within the limits of 100 to 150 feet. Figure 7 shows a system of terracing used by a grower in the San Luis Obispo area, but rarely used there or elsewhere in California. PREPARATION OF THE LAND BEFORE PLANTING If the strawberry planting is to be established on land that has been in sod for several years, it is desirable that the soil be carefully examined for the presence of white grubs and wireworms. If these are found in appreciable numbers, the population may be reduced by breaking up The Production of Strawberries in California 33 the sod and cropping the land to grain or other field crops for at least one year. Such procedure has the added advantage of not only reducing the weed problem but also greatly improving the condition of the soil. Where an appreciable unevenness in the land occurs and leveling is resorted to, it is usually necessary that someone familiar with surveying lay out the planting and determine where the flumes, roads, and under- ground water pipes (if such are necessary) are to be placed and then where the breaks in the level are to come. Taking accurate readings with the transit or level will be made easier if the land is plowed or cultivated and well pulverized and smoothed off with a float to eliminate minor inequalities. Obvious humps or hollows may also be eliminated before taking readings. To establish the line of level, fields may be blocked off with stakes in squares varying from 25 to 40 feet on a side, according to the unevenness, and readings may be taken at each stake. These are then charted on paper, and a line of level, the approximate cuts and fills, and the position of the breaks in level, can usually be determined by inspection. Deep or heavy cuts are inadvisable, as a rule, for if they exceed 2 or 3 inches, the plants set on such cuts will usually be noticeably affected, and fertilizer and extra care will be needed to obtain even approximately normal growth and yield. Situations may arise, how- ever, where a heavy cut is less objectionable than making breaks in the level at more frequent intervals, even though heavy cutting will result in exceedingly poor growth and production in the areas thus treated. When the breaks in level have been determined and the line of level established, grade stakes may be set at the proper depth at the points at which the original readings were taken and the soil moved until the level conforms with the grade stakes. Various ways and means of moving soil are in use, but the most satisfactory method is unquestionably the use of power equipment in which a large float-type leveler capable of picking up large quantities of soil and depositing it at the will of the operator is used. When power equipment or large levelers are not avail- able, various other types are used. (See fig. 8 for illustrations of types of levelers and floats.) Strawberry land is normally made as level as practical in the direc- tion of the row ; too much emphasis cannot be placed upon this practice. Close leveling is necessary in order to prevent the irrigation water — which usually, at least after the first few irrigations, does not soak in immediately — from running to one end or to a low spot in the furrow, flooding that part of the bed and underirrigating other parts. The Japanese growers, in particular, are very insistent that the beds be essentially level. Experience has taught them that time and effort spent in leveling is repaid many times over in the later care of the planting. 34 California Agricultural Extension Service [Cir. 113 Fig. 8. — i/pes or levelers used for leveling and lioatmg land before planting strawberries: A, a large manufactured type with pneumatic tires; B, a sturdy homemade type used for moving soil or floating off minor inequalities ; C, an inexpensive homemade type used in the central- coast district ; by tipping the cutting edge, soil can be picked up or de- posited at the will of the operator. The Production of Strawberries in California 35 It is desirable that the leveling of the land be done in the fall months previous to planting in the spring. At this time the soil is reasonably dry and cannot be seriously compacted and there is usually more time to do a careful piece of work. In the spring the land is often too wet, with the result that either the physical condition of the soil is greatly im- paired if leveling is done under these conditions or the planting is seriously delayed because the land cannot be leveled. Before planting, the land may be plowed or loosened with a cultivator or other tool that will not disturb the established level, yet place the soil in condition for planting. It is highly desirable that the soil be finely pulverized ; this insures, other factors being equal, a good stand of plants, and eliminates much of the subsequent expensive hand labor. Such a policy, even at the cost of a few days' delay in planting, will in the end be highly profitable. If the strawberry planting is to be set out on the contour system, the ground should be gone over sufficiently with a float to eliminate all minor surface inequalities and irregularities. This operation will greatly facili- tate the laying out of the row bed. When the plants are to be set out on raised beds, the last tool operation performed is the ridging. This is normally done with the power lister commonly used for many crops, the furrowing units spaced to give the bed the desired width. TIME OF PLANTING Most growers prefer to plant in the spring of the year after the ground warms and conditions are favorable for planting. Strawberries may be successfully planted at other times, but more care and attention is usually necessary. When set in late spring and if the soil is dry, a light irrigation prior to planting is advisable; otherwise irrigation should follow each day's planting. A good stand cannot be expected when the plants are set in dry soil, unless they are immediately irrigated. Planting dates for various districts are discussed under the individual districts, pages 46 to 53. NUMBER OF PLANTS REQUIRED TO SET AN ACRE The type of culture and method of planting will determine the num- ber of plants required to set an acre, which varies from 4,000 to 12,000 or more. These plants are used as the mother plants from which the run- ners grow. The latter are used to fill in and are spaced over the bed 6 to 10 inches apart as a rule. When these are set, the total number of plants may reach 60,000 or more per acre. A more detailed consideration of the number of plants required for the various systems of planting is given under the discussion by districts, page 45. 36 California Agricultural Extension Service [Cir. 113 TREATMENT AND STORAGE OF THE PLANTS BEFORE SETTING In the central valleys, local plants are often used. These may be dug any time during the late fall or winter months and heeled in in narrow rows until planting time. Preferably sandy, but at least well-drained, soil should be used for this purpose. The soil is well firmed around the roots, which must be entirely covered ; but care should be taken not to cover the crown. The plants may remain heeled in until growth starts in the spring if it is not possible to plant earlier. Nonlocal plants are usually ordered and shipped as needed and are kept in the shipping box or basket until planted. It is the general and successful practice to have everything in readiness so that when the plants arrive they may be set immediately. If planting is delayed by rain, the boxes of plants may be held for a short time by placing in a cool location, such as at the north side of a building or in an open shed. When some method of holding for a considerable time after digging becomes necessary, cold storage at 32° to 36° Fahrenheit with a mod- erately high humidity is practical. If the storage period is much more than a month, it is advisable to repack the plants, alternating layers of plants with layers of damp sphagnum moss. The plants and moss should not be too tightly compressed ; for if aeration is insufficient, injury may develop and cause a breakdown of root tissue. Likewise, the sides of the box should be constructed so as to permit adequate ventilation. Al- though it is not recommended, except for emergencies, plants have been held satisfactorily by this method for over six months. SETTING THE PLANTS Before setting, the plants are trimmed, a process which consists of cut- ting off the leaves (if this has not already been done at the time of ship- ping) , cutting the roots back to about 4 inches in length, and usually removing dead and dried petiole bases from the crown (fig. 9). This removal of petiole bases is probably important only when there is evi- dence of decay in the crown. Small and weak plants are sorted out and likewise any that have diseased roots. Many growers discard all plants that show any root discoloration, but this practice is not justified if the core of the root is white and the darkening is limited to the surface tissues. Plants showing black sunken areas on the outside of the root or a brown core inside should be discarded. Further discussion of root troubles is given under that heading, pages 83 to 87. If the plants at the time of setting show any indications of drying or are to be set in ground that lacks sufficient moisture, they may be soaked in water for a few minutes just before planting out. The Production of Strawberries in California 37 Whatever method may be used in setting the plants, there are two items of importance. These are (1) setting the plants at the correct depth, and (2) making the soil very firm around the roots. When setting is completed, the crown of the plant should be even with the surface of the soil, with no part of the root exposed. The plant on the right in figure 9 illustrates the proper depth to plant. The firming of the soil around the roots excludes air pockets and thus prevents drying of the plant Fig. 9. — A, Plant as dug, before any trimming; B, leaves cut off ready for packing into shipping box ; C, roots trimmed ready for planting. The dotted line indicates the level at which the soil should be when the plant is set : deeper plant- ing may cause the crown to rot ; shallow setting exposes and dries the roots. until new rootlets are formed. Never expose the dug plant to direct sun- light for any appreciable period of time. The roots are small and tender, and even short periods of drying may cause injury sufficient to inter- fere with starting. A variety of tools, including the shovel, trowel, hoe, and dibble, are used in setting the plants. The trowel is ordinarily used by the Japanese. They usually dig a hole to the depth to which the roots are to be set, loosen and pulverize the soil in the hole, spread the roots out fan-shape against the side of the hole, fill partly with soil, tamp carefully with the head of the trowel or press firmly with the thumb and fingers, add the remainder of the soil and again firm well and finally brush a little soil over the firmed surface to prevent "baking." This is a slow and tedious method, a good worker being able to set only 1,200 to 2,000 plants a day. It is 38 California Agricultural Extension Service [Cir. 113 doubtful if so much care is important or has any advantage over a more rapid and less painstaking method. Strawberries have been and can be successfully planted, if the soil has been well prepared, with a flat trowel or spadelike tool. This is inserted in the soil to a depth of 4 to 5 inches and pulled forward to make a V-shaped opening, then the roots of the plant are spread fan-shape into the y and held with the hand until the tool can be removed. The soil may then be firmly pressed into the V with the tool, by the hand, or with the heel of the operator's shoe, or with a combination of these movements. A regular garden spade may be used instead of the smaller tool and by merely bending over, the operator may follow the procedure as outlined. Skill can be acquired in this method of planting so that 4,000 to 5,000 plants may be set in a day by one workman. As mentioned in a previous section, it is advisable, if the soil is dry or the weather warm at the time of setting the plants, to irrigate imme- diately. Plants should not be allowed to wilt. After they have once become well established, they may receive rather severe treatment and yet survive, but when first set out they need good care and attention. CULTIVATION AND CARE THE FIRST YEAR When strawberries are set on raised beds, all cultivation of the bed must be done by hand. Hoeings are given often enough to keep the surface of the ground pulverized and to prevent crusting after rains. The furrows are cultivated with a single-row horse cultivator after irrigations or heavy rains. If clods are formed, a small clod-masher type of drag is used to break them. Frequently growers use a Y on the front of the drag to build up the sides of the furrow that have been disturbed or broken down during cultivation. The strawberry is shallow-rooted, and conse- quently cultivation as practiced by the growers is not deep. "Weeds are removed at intervals. Normally very little cultivation is required during the first season. Removal of Flower or Fruit Stems. — Flower or fruit stems usually appear soon after the plants are set in the spring, and in most instances are removed as they appear. If the fruit is allowed to mature before the plants are fully established, there is a serious drain on their vitality, which may result in insufficient development of healthy runner plants. If the plants are growing vigorously, there is little harm in allowing the fruit to mature ; but the practice is seldom followed in commercial plantings. Setting of Runner Plants. — After the plants become well established, usually in early summer, they produce runners or stolons on which the new plants are formed. These may be set as soon as they develop two or The Production of Strawberries in California 39 three leaves, but there is considerable saving in labor if the setting is delayed until there are sufficient plants to fill the bed at one operation. It is, nevertheless, inadvisable to allow the runner plant to become very old before setting because the development of roots from such a plant is seldom satisfactory. After the bed is set, the remaining runners are pulled or cut off, and as more develop they are periodically removed in order to maintain the vigor of the plants already set. Since the removal of runners may become a rather burdensome task in varieties that pro- duce large numbers, the practice of removing the early runners and set- ting the beds with those developing later is sometimes followed; this obviates some of the work necessary in runner control. The most effective method of setting the runner plant is to turn the soil with a trowel at the point where the plant is to be set. This brings moist soil to the surface into which the plant, while still attached to the runner, can be pressed by the thumb and forefinger to a depth sufficient to hold it in place. As an added measure of insurance that the plant be held in position, some planters place a small clod on the runner close to the plant. If the soil is moist, roots will develop immediately ; for this reason, irrigation just prior to setting is advisable. As a rule, runner plants are not allowed to root in the furrow unless plants are needed for filling in vacant spots where the original plants have died, or for new plantings. It is generally agreed that permitting excessive runner plants to develop in the furrows after the beds have been set tends to reduce yields the following spring. Irrigation the First Year. — The amount of irrigation will depend upon the climatic conditions that prevail in the district and upon the soil type. In an extremely hot area like the Imperial Valley, regular irri- gations once each week from the time of setting may be necessary ; but in the cool coastal areas, plantings are sometimes carried through the first year with as few as two or three irrigations. A sandy soil will gen- erally require more frequent irrigation than a heavy one. Along the central coast, growers have found by experience that heavier yields result the second year if growth is moderately retarded by irrigating just often enough the first year to prevent their wilting noticeably : lux- uriant growth the first year is not desirable. Fertilization the First Year. — Fertilization is not generally practiced on strawberries the first year but probably a moderate application, particularly of nitrogen on the poorer types of soil and on areas where heavy grading has occurred, would be profitable. This should be made in late summer or early fall. An amount equivalent to 250 to 400 pounds of a 20 per cent nitrogen fertilizer would make a good application and should not cause excessive growth. 40 California Agricultural Extension Service [Cm. 113 CARE OF THE PLANTING THE SECOND YEAR The second year is normally the first year of fruit production, and every effort is made to obtain a maximum yield of marketable fruit. If impor- tant details are neglected, production is reduced and the result may be an unprofitable planting. Where insects and diseases are prevalent, control of them must be carefully planned. Other items pertinent to the care of the planting will be discussed in the following paragraphs. In sections of the state other than the central coast, the tops are not usually cut, there being less trouble from red spider, aphids, leaf spot, and mildew, which are partially controlled by removal of the foliage. The tops die down and act as a sort of mulch, which prevents to some extent the splattering of the soil onto the developing fruit during heavy rains in the early spring. In the central-coast district, the tops are removed as an aid in control of the insects and diseases mentioned. (See p. 49.) The beds are hoed before or about the time growth starts and the fur- rows are thoroughly cultivated and refurrowed. The drag clod masher follows the cultivator if the furrow has been left in a lumpy state. Sub- sequent hand work may be necessary on top of the bed to break the crust formed after rains. As the ground becomes covered with the leaves of developing plants, cultivation ceases. A mule or small horse is better suited for purposes of cultivation in a strawberry planting than is a larger animal. Horse cultivation is normally not practiced after the fruit begins to ripen because of the resultant injury to fruit hanging over the sides of the bed. The furrow may be cultivated again between crops. Weeding is done by hand. The time that irrigation must be started will depend largely upon weather conditions. If the weather is dry, irrigation may be necessary as early as March in the interior valleys. The strawberry is a very shallow- rooted plant, and adequate moisture must therefore be maintained in the surface soil for normal plant development and the attainment of maximum fruit size. If the soil is allowed to dry appreciably, there is also danger of red-spider attack even though the direct effect is not serious. With the advent of harvest, irrigating immediately after each picking throughout the season is a common practice. As the weather becomes warmer, pickings are more frequent and thus the irrigations may be at 4- or 5-day intervals. In the interior valleys during periods of excessive heat or in light sandy soils, irrigations at 2- or 3-day intervals may be needed to maintain adequate soil moisture. In the cooler sections of the state, irrigating after each picking may not be necessary, but seldom will The Production of Strawberries in California 41 there be sufficient moisture retained to carry over until the second pick- ing has been made ; and if irrigated halfway between pickings, the fur- row may be undesirably wet at the succeeding picking date. Irrigating immediately after each picking is therefore a rather general custom throughout the state. With this practice, irrigations are frequent but relatively light, that is, the furrows are only partially filled. This is a desirable feature in most soils, for it keeps the surface of the beds dry, which is essential in preventing decay of the berries. If experience indi- cates that in a particular soil such irrigations do not penetrate to the center of the bed, the width of the bed may be reduced. Irrigation as practiced in strawberry plantings is necessarily some- what wasteful of water because of the short interval between pickings and because of the width of the bed, which requires that sufficient water be added to the furrow to penetrate laterally to the bed center and thus keep the plants growing normally. Spraying or dusting may be necessary during the growing season if pests or diseases appear. Recommendations for their control will be dis- cussed under the section on diseases and pests (pp. 70-89). Harvesting. — The strawberry is an exceedingly perishable fruit and must be harvested regularly as the fruit ripens. If allowed to become overripe, it deteriorates rapidly in both quality and appearance after being picked. On the other hand, state and federal standards require that the berry reach a certain maturity before it is offered for sale. (See "Strawberry Grades and Standards," p. 61.) Frequent pickings must be made, but the interval between will depend upon the temperatures prevailing and may vary from 2 to 6 days. With the extremely high temperatures that occur in Imperial Valley, picking every other day may be necessary ; whereas in the cool coastal section at the beginning of the season, as much as 6 days may be required for the berries to ripen. Under average spring temperatures, 2 to 3 days is a normal interval be- tween pickings in the interior, and 4 to 6 days along the coast. Frequent pickings are desirable but the extra cost may offset the extra return from such a practice. In California practically all strawberries are picked directly into the baskets in which they are to be sold. All sorting is done by the picker as the fruit is picked, and any ill-formed, partly decayed, or cull berries are dropped in the bottom of the furrow. It is important that all ripe berries regardless of their value be removed from the plant at each pick- ing in order to reduce the amount of decay in the remainder of the crop. In most strawberry areas of the state only the first-grade berries are sold. Occasionally in the Los Angeles district, where the Klondike is the favored variety, small berries are saved and sold locally at roadside 42 California Agricultural Extension Service [Cm. 113 stands. This variety tends to produce small berries at the end of the season, especially in plantings more than two years old. Berries for market are picked with the calyx attached. The picking is accomplished by grasping the berry between the thumb and first two fingers of either hand and breaking or pinching the stem off with pres- sure from the thumb or thumbnail. Considerable skill is gained, and at Fig. 10. — A partially filled chest containing when full 16 drawers of 6 pint baskets each. This type of carrier was originally used extensively in the central-coast district but has now been largely replaced by the 12-basket crate. times an average of better than 2 crates (of 12 pint baskets each) per hour are picked by experienced workers. Various types of basket carriers have been devised for picking. Usually a tray with a capacity of 6 or 8 baskets and equipped with a handle, sometimes on legs and sometimes not, is used. When this is filled, the baskets are deposited at the end of the row in crates, chests (fig. 10), or other equipment for transportation. Some of the growers in the Watson- ville area pick directly into 12-basket crates; the latter are set on a wheeled device (fig. 11) that can be pushed along ahead of the picker. This saves the time of transferring the baskets from the tray to the crate and is easier for the picker because he can push the container instead of lifting it each time it is moved. The picked berries are placed in the baskets in either faced, semif aced, or jumble pack. The fullfaced pack, in which the berries are arranged uniformly over the surface with the bright red side up and no calyxes showing, has the best appearance but requires more time to prepare than The Production of Strawberries in California 43 the others. There is also somewhat of a tendency to prepare a deceptive pack when berries of a uniform size are used to face with. This method of packing is gradually being discarded and replaced by the semifaced pack in which the berries in the top layer are mostly placed with the calyx down and the red side exposed but not uniformly arranged. In the jumble pack the fruit is dropped in the basket and falls as it may. The calyxes and stems may show and the pack is inferior to the others in ap- Fig. 11. — Wheeled crate carrier as used in the Watsonville area. By picking directly into the crate, the necessity of rehandling the berries or baskets is elimi- nated. The carrier is pushed ahead of the picker. When the baskets at one end are filled, the crate may be reversed on the carrier. pearance. The semifaced pack requires but little more of the pickers time and skill yet is much more attractive. The picked berries while in the field should always be protected from the direct rays of the sun either by a cloth covering or shelter of some kind. Figure 12, A, shows a light movable type of shelter used in the Imperial Valley, where temperatures are extremely high. During pe- riods of excessive heat, the berries are usually stored during the day in some place cooler than the field shelter, in order that they may arrive on the market in a first-class condition. Ordinarily the picked fruit is gath- ered up from the field periodically during the day by small pickup-type trucks and carted direct to market if sold locally or hauled to a loading station where shade or a cooled room is available and held until called for by large trucks making daily trips to the important markets or rail- road shipping points. Improvised water coolers in which water is allowed to trickle down over a shaded burlap-covered room are occasionally used in or near the 44 California Agricultural Extension Service [Gib. 113 field in the interior valleys and provide inexpensive means of keeping the berries cool until transported to market. In some instances, growers have solved the problem by building mechanical-refrigeration units close to the field to precool the fruit before shipment. During the peak of the picking season, extra pickers are normally required. In the larger strawberry sections of the state they are recruited from Filipino, Mexican, or Japanese labor ranks. This help is usually Fig. 12. — Equipment used in strawberry plantings: A, a type of shelter for picked berries used in Imperial Valley ; B, a roll of kraf t wrapping paper used for protecting beds against frost during the winter period ; C, a tray carrier with cloth shade ; D, a ditching tool ; and E, a redwood-pipe inlet for irrigation water. paid by the hour and seldom by the crate, the chief objection to piece work being that workers do not sort the fruit satisfactorily and place culls in the basket. Fertilizing. — Fertilizers of one kind or another are used by many strawberry growers. Some claim that no benefits are derived from mod- erate amounts of commercial fertilizers and do not use any. Surpris- ingly, berries will often do reasonably well without the use of fertilizer on land considered extremely poor for other crops. There is a distinct lack of definite information concerning the fertilizing of strawberries in the several districts of the state, and practically all of the so-called "complete" fertilizers are used without any certain knowledge as to whether or not beneficial results are to be had from all of the component parts. There is reason to assume and some trials give evidence that nitro- The Production of Strawberries in California 45 gen is helpful, particularly in soils low in this element. When very light sandy soils are used, a complete fertilizer — that is, one containing nitro- gen, phosphate, and potash — may give best results ; but in the majority of the California soils, little benefit is normally derived from the addi- tion of phosphate and not much more from potash. More precise infor- mation concerning the use of fertilizers is necessary before accurate statements can be made. The excessive use of nitrogen, whether alone or in combination with other fertilizers, is to be avoided because of its tendency to soften the fruit and weaken the skin, which predisposes the fruit to mold and decay and results in lowering the keeping quality in transit and on the market. A total of 1,000 pounds per year per acre of a 20 per cent nitro- gen fertilizer would not be an excessive amount for fertilizing strawber- ries if the material was applied in three or four applications. It would be undesirable to apply more than 350 to 400 pounds of such a fertilizer at any one time. Many growers believe that potash adds color to the fruit and tends to harden the skin and in a measure counteract the softening effect of nitrogen. The scientific proof for the latter opinion, however, appears to be lacking. An increasingly popular method of applying nitrogen to the straw- berry planting is by dissolving a soluble nitrogenous fertilizer in water and allowing the resultant liquid to drip into the irrigation water from a drum or barrel during irrigations. If the time required to irrigate an acre is known, the rate of flow of the fertilizer from the drum can be so regulated that the correct amount of fertilizer is applied. This method allows the fertilization of the berries at any time of the year when irri- gation is practiced and does not damage a ripening crop as would adding fertilizer to the bottom of the furrow and working it in by cultivating tools. A better and more uniform penetration of the fertilizer into the bed is also accomplished by this method of application. Agricultural ammonia (NH3) has been successfully used in the nitrogenous fertiliza- tion of strawberries. CULTURAL AND OTHER PRACTICES IN VARIOUS DISTRICTS As indicated in previous sections, the practices followed in one district of the state may vary appreciably from those in another. It will be the purpose of this section to discuss those followed in each of the more or less distinct geographical strawberry districts of the state as shown in table 3 if these practices differ from those given in the general discus- sion on the preceding pages. 46 California Agricultural Extension Service [Cir- 113 The prospective grower should always acquaint himself with the methods followed in the district by other growers and not be too quick to change some accepted one. The practices in any district are usually founded on many years' experience, and though improvement may be possible in some respects, any radical change should be carefully consid- ered and tried out on a small scale to prove its worth before adopting it generally. New varieties are continually being developed, tried out in districts, and discarded. Occasionally one is found that appears to possess su- perior qualities. If, after thorough trials, its superiority is demonstrated, the variety is gradually adopted and the old one is replaced. Frequently more than one variety is grown in a district and in some several are used, each possessing some favorable quality such as high production, disease resistance, fall production, or longevity. Any statement regarding the varieties grown in a district is necessarily correct only at the time it is made. Prospective growers should investigate the merits of all varieties grown in the area in which they locate before deciding upon a variety or varieties to use. New varieties should be given a thorough trial before planting on a large scale. Old varieties not grown in the district are sel- dom worth trying out ; for usually they have been tried and discarded many times in the past. (See the discussion of varieties on p. 64.) Table 12 summarizes some of the important differences between dis- tricts. Naturally there is no definite line of demarcation between the districts, and the practices followed in one may overlap or be used in part by others. Under "varieties used" are listed the principal ones used in the district by commercial growers and in the "less important" col- umn are given those used occasionally or not thoroughly tested for the district but which have shown promise in one way or another. For a de- scription and more detailed information on each variety see under "Va- rieties" on page 64. CENTRAL-COAST DISTRICT As previously mentioned, the culture in the central-coast district is the most intensive of any within the state, and acre yields are larger than for any other part of the United States. One reason for this heavy yield is the length of the producing season, which usually extends from April to December. The length and continuity of the fruiting season are modi- fied by (1) the variations in climate from season to season, (2) the variety used, and (3) the specific location in the district. In no other district of the state is this continuous production consistently obtained. The raised-bed spaced-row system is uniformly used throughout the dis- trict, and the beds are commonly spaced 42 inches from center to center. Two rows of plants are usually set on the bed, and the plants in the rows The Production of Strawberries in California 47 13 < 9 o Eh < Ph 02 C f$ C it •s 2 CO O Tl T3 -^ T3 ^ c3 ^ c3 T-t D. 73 a <^ (O $ii h-1 1^ P CC -TJ o a> o3 3 Q tf ^ tf 3 ra be £ S -s .=3 ^ ^ c =« S 01 a; b O c iU '^ pq S S ^ § 1 § § 01 U Is 03 .S 48 California Agricultural Extension Service [Cir. 113 are spaced from 24 to 36 inches apart and alternated on opposite sides of the bed. The number of plants required to set an acre on this system varies from 9,000 to 12,000. As runners form, the spaces are filled in and the spaced row is the result. Contour planting is frequently em- ployed on rolling land (fig. 6 A, B). Wooden flumes are generally used to distribute the irrigation v^^ater (fig. 13). Fig. 13. — Main flume with laterals as used in the central-coast district. A center roadway is left between adjoining beds. The small pieces of board be- side the lateral flume are used as baffles in the bottom of the flume to force the water through the outlets shown stoppered with barrel bungs. When in use, the board is wedged against a nail in the bottom of the flume. Of the varieties in general use. Banner is the oldest and is still the most popular in Alameda, Contra Costa, San Mateo, and Santa Clara counties. In the Watsonville-Salinas area, Nich Ohmer has largely re- placed it and Dorsett is also grown in some plantings. During seasons favorable to summer and fall production, the Narcissa and Redheart appear to be valuable varieties, and in areas where climatic conditions favor this type of production, they are worthy of trial. Practically all kinds of soil are used in this district, but there is a preference for the lighter, more easily worked types. Strawberries are very seldom replanted on land that has previously been cropped to this fruit, even after rotation with other crops. Some of the larger and more experienced growers prefer to isolate their plantings several miles dis- tant from other strawberries and to plant either on virgin soil or on old hay or orchard land. Less root troubles are encountered on such land, and if disease-free plants are set with proper precautions for mite con- The Production of Strawberries in California 49 trol, excellent results are often obtainable. Isolation is highly recom- mended. February, March, and April are the favored months to set out straw- berries here. From the standpoint of yellows control, the later the plants are set in this district the less are the chances for infection ; hence it is recommended that planting be delayed until after the middle of April. This is more important if a susceptible variety such as Marshall is used, and particularly if there is an old diseased field nearby. Late planting involves somewhat more care immediately after the plants are set, but -sMWo. 'asua^msss^ ,*».-m'5'' <%«!«'. Fig. 14. — Picking strawberries in the Mt. Eden area of Alameda County (cen- tral-coast district). Drawers containing 6 baskets are used to pick into and when full are placed in carriers holding 4 drawers as shown in the foreground. When the carriers are filled they are gathered up and the drawers placed in chests as illustrated in figure 10. experimental plots have shown conclusively that when the hazard of infection is present, the results more than compensate for it. In the central-coast district, the first operation the second year, usually late January or February, consists of topping the plants, or removing all leaves, both live and dead, and burning them. The plants are cut close to the soil level with a tool similar to a small hand sickle. This is a sani- tary measure and tends to do away with red spider and aphids that may be living on the leaves during the winter. It also checks the spread of the leaf -spot diseases and mildew by removing the source of contamination. This procedure is frequently followed by either a light oil spray designed to destroy the remaining insects or a lime-sulfur spray designed to kill both the insects and fungi missed in the removal of the leaf debris. All parts of the bed and furrow are thoroughly sprayed. This spray is neces- sary only if spider, mildew, or leaf spot has been present the year previ- ous and is not recommended if none of these was in evidence. 50 California Agricultural Extension Service [Cir. 113 SACRAMENTO DISTRICT The major portion of the strawberries in the Sacramento district are grown on shallow hardpan soil. Many plantings have been started as an intercrop in young vineyards. The berries are set at the same time as the grapes and their culture discontinued when the vineyard attains bearing age. An unusual type of culture is followed and is illustrated in figure 15 : the plants are set 3 feet apart in a single row along the top Fig. 15. — Method of culture used in the Sacramento district on hardpan land. The deep ditches are used for irrigation while the center pathway is used for picking berries. Cross ditches distribute the water to those which run lengthwise. of the ditch bank, approximately 5,000 plants being required to set an acre by this method ; as runners develop, a spaced row 2 to 3 feet wide is made. The deep ditches surrounding the beds are filled with water when irrigation becomes necessary. The impervious hardpan prevents the water from moving downward, which results in the subirrigation of the bed. The berries are picked from the center pathway, hence irri- gations do not interfere with picking and may be given whenever neces- sary. Many of the plants used in this district are grown locally and pro- duced very inexpensively. The runners are allowed to root in the ditches, which is possible only because the latter are not used for picking or cul- tural operations. The plants if properly matured are sometimes dug and set out during the fall months but the most common practice is to heel the plants in in the late fall and set them out in early spring. The strawberries grown in this district are sold under the name of The Production of Strawberries in California 51 "Oregon Plum." There appears to be no justification for this name other than as a trade name for the Marshall type of berry which is predomi- nantly grown here (see p 65). SAN JOAQUIN VALLEY DISTRICT Numerous plantings and minor districts are scattered through the San Joaquin Valley. Fresno is the principal shipping point, and the limited Fig. 16. — Diagram of an irrigation system used to some extent on hardpan land in the Fresno area. Single-row raised-level bed, 20 to 30 feet in length. Arrows indicate the direction of water flow, which must of course start at the highest point. interstate shipments from the district originate chiefly in the vicinity of this city. The major portion of the crop is disposed of locally or in the San Francisco, Oakland, or Los Angeles metropolitan areas. The Marshall-type berry is grown almost exclusively in the larger plantings in this valley. While other varieties have been tried and are 52 California Agricultural Extension Service [Cir. ii3 used in limited numbers, they are considered to be inferior to the Mar- shall type as a commercial market berry. However, because of the prevalence of the yellows disease and the susceptibility of the Marshall to this trouble, growers may eventually be forced to use some other variety if one can be found suited to the district. Several irrigation systems are used, the choice depending in part upon the contour of the land and the character of the soil. Figure 16 illustrates diagrammatically a system employed on some of the hardpan and slightly rolling land northwest of the city of Fresno and not ob- served to be used elsewhere in the state. Water is distributed from the highest point through main and lateral ditches. The land is leveled in the direction of the rows but need not be entirely level in the other. Any slight grade is taken care of by forcing the irrigation water back and forth across the plot to slow down the rate of flow. In the nonhardpan soils, the simple raised-bed system as used along the central coast, with a double or spaced row, is commonly employed. From 8,000 to 10,000 plants are required to set out an acre when this system is used. In the San Joaquin Valley, a few plants are sometimes set as early as December, a larger number are planted in January, but most of them are set in February and March. The early-set plants do not grow better, but the grower is given the opportunity to finish the planting and early- spring work in the new patch before the picking season. This is espe- cially desirable when growers plan, as many do, to add a few acres to the original plantings each year to compensate for the abandoning of older acreages. LOS ANGELES DISTRICT Strawberries in the Los Angeles district are usually set out flat-culture on land previously leveled in the direction the furrow will eventually run. The plants are spaced at 3-foot intervals in rows 4 feet apart and allowed to grow in this manner until runners are ready to set. Approxi- mately 4,000 plants are required to set out an acre. When irrigation is necessary, shallow ditches are run down the rows. After sufficient run- ners have developed, the furrows are made with a single-row ridger having a 16-inch shovel and drawn by a horse. While a furrow is being made, the runners are pushed away, then are returned to the resulting ridge before making the adjoining furrow. The ridges are smoothed by hand labor. The runners are spaced 8 inches to 1 foot apart, usually in double or spaced rows. Sometimes wooden flumes are used to distribute water and at other times open ditches. Much of the land utilized for strawberry production in the Los An- geles district, situated southeast of the city and extending roughly from Compton to Garden Grove, is of the low-lying, light-sandy type, and The Production of Strawberries in California 53 considerable trouble is encountered from alkali and high concentrations of salts in the soil. The poorest of this land should be avoided when select- ing a site for planting strawberries. The Los Angeles district is far enough south so that as a rule only the varieties which do well in the southern states succeed. The Klondike, Fig. 17. — A, Thirty-basket crate with hinged top and "middle" divider used for local market shipments in the Los Angeles district ; B, basket carrier used for picking berries. although not entirely satisfactory, is the favorite and is used in a major- ity of the plantings. In southern California the planting season extends from February to April, but most of the plantings are set in March. A 30-basket, double-deck type of crate is used in this area for local shipments (^g. 17, A), The crate when empty is returned to the grower. When berries are shipped outside the district, 12-basket crates are normally used. IMPERIAL VALLEY DISTRICT The type of culture used in the Imperial Valley has several unique features. The intense heat, the heavy deposits of alkali, and the desire to produce fruit extremely early in the season are factors calling for a special type of culture. To obtain early fruit, some protection must be given the plants from the cold north winds that frequently sweep across the Valley. This is accomplished by the erection of paper windbreaks. The rows of straw- berries are set east and west, and the windbreak, consisting of butchers' heavy wrapping paper, is placed on the north side and slanted over the bed so that it partially covers the row of plants. The paper is 12 inches in width and held between a double row of sticks forced into the ground. Unless violent winds and rain occur, the paper lasts a season. The sticks 54 California Agricultural Extension Service [Cir. 113 are obtained from a brush known locally as "aloeweed" and are gathered and cut into the desired length largely by Mexicans across the border. The system of culture is a modified raised-bed double row, in which approximately 8,000 plants are set per acre. The ridges are made as an inverted V with a sharp angle at the top. The plants are set halfway or more down the side of the ridge and the upper part is kept free of plants. This arrangement allows the alkali and salts present in the soil and Fig. 18. — A method of irrigating berries in Imperial Valley. Redwood-pipe outlets conduct water from the main ditch to individual furrows. added by the frequent irrigations to collect at the top of the ridge. The heavy incrustations that form are removed two or three times a year. The alkali is scraped to the center and top of the ridge, picked up with a shovel, and hauled out of the field. If flat beds were to be used at the time of setting, the alkali would collect around and soon injure the plant. With a sharp ridge, the alkali and other salts rise above the plant and cause little injury except when rain (which seldom occurs in the Valley) washes them down around the roots. For this reason, rain at any season of the year is undesirable. Figure 18 illustrates a type of irrigation sys- te}n used in the Valley. Crops of only moderate size are obtained in the Imperial Valley, and with the numerous difficulties involved in the culture, the acreage is definitely on the decline. If periods of high prices again prevail, interest in the crop in this section may be revived. The Production of Strawberries in California 55 OTHER DISTRICTS Eureka, San Diego County, San Luis Obispo and Santa Barbara coun- ties are strawberry districts of minor importance in comparison with the first four of those discussed above. Figure 19 illustrates a type of culture used to some extent in San Diego County. The rows are very long, and a trough-type flume distributes the irrigation water. Strawberries are grown in small plots or home gardens in practically all parts of the state and are sold locally or consumed by the individuals Fig. 19. — Strawberry culture in San Diego County. Eows are long and a trough-type flume with outlet holes near the bottom and covered with wooden buttons is used. growing them. Numerous and varied practices are followed by these small growers, many of whom are of the white race. Local conditions and the energy, ambition, and circumstances of the operator largely determine the practice that an individual follows. Efficiency of operation is not always a factor. Short-cut methods are often employed ; sometimes they are successful and other times not. As a rule, whenever a grower is uncertain as to the type of culture to use or the variety to plant, it is safe to follow the practice of the closest large district. PROPAGATING AND HANDLING PLANTING STOCK Strawberries are normally propagated only by the use of runner plants, but they may be propagated by dividing the crown or from seed. Division of the crowns to make new plants is too slow and expensive for general commercial use, and this method of propagation is seldom needed ex- cept in the Rockhill everbearing variety, with which a paucity of run- ners occasionally necessitates its use. Plants grown from seed usually bear fruit inferior to that of the parent plant and seldom is there more 56 California Agricultural Extension Service [Cm. 113 than a single plant out of several thousand seedlings that has commercial value. By the crossing of varieties and the pyramiding of characters, new and superior varieties are sometimes developed, but thousands of seed- lings are usually necessary to obtain one superior variety. Strawberries are not usually propagated on heavy or clay soils be- cause their roots are fragile and cannot be satisfactorily separated from such soil without breaking. Where possible, a sandy or loose, friable loam that allows the production of long, white, nonbranching roots should always be used for this purpose. The digging of the plants at the time of shipment is done with a potato hook. Care should be exercised that the dug plants are not injured by exposure to the sun or drying winds. As stated before under "Treatment and Storage of Plants before Set- ting" (p. 36), the trade prefers to use plants that are dug and shipped as needed for planting ; and where possible, orders are so placed that the plants arrive the day they are set out or the day before. Shipments from northern California and Oregon ordinarily come in slatted wooden boxes, somewhat resembling apple boxes, usually containing 1,000 of the large Marshall-type plants or upwards to 2,000 of the smaller Nich Ohmers. The plants are arranged with the tops toward the outside of the slatted box and the roots in and are very firmly pressed into the box. Moistened moss or burlap placed on the top and bottom of the box pre- vents drying. Plants shipped in this manner, before growth has started, may, if necessary, remain in the box for a week and longer during cool weather without injury. After growth has once started, however, there is danger that heating during shipment may result in blackening and spoilage of the roots, particularly if warm weather prevails. Under these conditions, the plants should not remain in the box longer than necessity requires. Heating may also result if the plants at the time of packing have free moisture on the foliage or roots, and consequently it is unsafe to pack plants when wet. Commercial shipments of straw- berry plants are usually forwarded by rail express or trucked direct. Planting stock should have made very little growth before it is dug ; and in districts where late planting is practiced, the stock should come from districts where spring growth is checked and held back by pre- vailing cold weather. Furthermore, some varieties, those of the Marshall type being extreme cases, require an appreciable amount of cold weather before the rest or dormant condition is broken and before vigorous growth can be expected to start in the spring. Along the coast or in the southern part of the state, where the weather remains warm during much of the winter, locally grown plants of those varieties that require cold weather to break the rest period often fail to grow vigorously when set out, and it is advisable to use northern-grown plants. The Production of Strawberries in California 57 In most areas where plants are propagated, virus diseases are present ; and unless the propagator makes some effort to maintain disease-free stock by careful roguing out of the diseased plants, the trouble may continue to spread until his entire planting stock may become diseased ; this is particularly true of yellows. Unfortunately the symptoms of this disease are masked by the warm summer weather prevailing in most of the propagating districts, and detection of the disease is often very diffi- cult even for experienced persons. Yet, when the plants are set out in districts favorable to the development of the disease, the symptoms be- come evident and the destructive nature apparent. When possible to obtain stock certified free of virus diseases, growers should avail them- selves of it. This is especially important when planting in isolated areas. There is a trade preference for plants propagated from mother plants in their first season of growth; those that originate from plants two years old or more are considered inferior. Propagators therefore plan on setting out sufficient plants each spring to produce the quantity of runner plants desired for sale the following spring. Since fluctuations of demand are not always anticipated a year in advance, planting stock may be insufficient in some years and abundant in others. SHASTA AREA A considerable portion of the planting stock used in central California is grown in a narrow belt along the Sacramento River in the northern part of Shasta County. The red volcanic ash soil in this region is par- ticularly adapted to growing vigorous plants with long, white roots. Propagators in the area are not concerned with the production of fruit and grow strawberries almost entirely for the plant trade. Two systems of culture are used : the most popular is fiat culture with overhead irri- gation, but many plants are grown on the furrow-ridge system. These methods of growing are illustrated in figure 20. If weather conditions permit, it is preferable to plant the propagat- ing beds in February or early March. During the hot summer months, to insure proper rooting, the bases of the runner plants must usually be pushed into the soil as they form. If this is not practiced, the surface of the ground may dry so rapidly after irrigations that the plants fail to catch root. During the fall months when there is less rapid evaporation, the runner plants will usually root without this extra attention if suffi- cient moisture is given them. The setting of the runners early in the summer favors an increased yield of plants because the first-set runner plants will in turn produce more runners later in the season. Heavy fertilization of the soil is necessary for a satisfactory yield of plants, and ordinarily sheep or goat manure is used. A three- or four- 58 California Agricultural Extension Service [Cm. 113 Fig. 20. — Propagating strawberry plants in upper Sacramento Eiver canyon: A, overhead system of irrigation; the sprinklers are changed each hour. B, Eaised-bed system ; a very small stream of water is allowed to trickle down each furrow; the stony soil prevents erosion. The Production of Strawberries in California 59 year system of crop and summer-fallow rotation is followed when pos- sible. Depending upon the variety grown and the season, a yield of salable plants varying from 150,000 to 350,000 per acre may be expected. A major portion of the stock grown in the Shasta area is used in the central- coast district. Some is used in the central valleys. SACRAMENTO DISTRICT Locally grown plants are used extensively in the Sacramento district and relatively few are brought in from outside. Practically none are shipped to other districts of the state. The system of culture, described in the discussion of district practices and illustrated in figure 15, is such that the production of plants costs practically nothing in extra effort, and the plants can therefore be sold for a relatively low price and under the cost of production in the regular plant-producing areas. There seem to be no ill effects from the use of local plants in this area provided selec- tions are made from fields free of virus diseases, or, if such diseases are present, provided the planting stock is selected only from the healthy plants in the field. Care must be exercised to mark the diseased plants at a season of the year when symptoms are evident. (See under "Yel- lows," p. 79). Normally the plants are dug in late fall or early winter and heeled in until set out. TURLOCK AREA A limited amount of planting stock is propagated in a small area a few miles east of Turlock. The soil is sandy and produces exceptionally well- rooted plants. The mother plants are set on narrow ridges with wide alternating furrows, where the runner plants take root. The beds are run on level grade. As the irrigation water is forced through the furrow, it tends to cover the plants with sufficient sand so that roots form readily, and hand-setting of the first runners is not necessary. The system favors a heavy production of plants. A portion of the Nich Ohmer stock used along the coast is grown in this area. Banner stock from the district is less popular, however, seemingly because of the yellows disease occur- ring in it. FRESNO AREA Many of the plants used in the Fresno area are of local origin and are largely the result of allowing some of the first-year plantings to produce runner plants in the furrows after the number necessary for fruit production have been set on the top of the bed. They are dug and planted as needed the following winter or spring. The chief objection to this method of propagation is that virus diseases, principally yellows, develop in the stock and are not rogued out. Plantings resulting from 60 California Agricultural Extension Service [Cm. 113 such virus-infected stock degenerate rapidly. In addition, the yield of fruit from plantings used for plant production is reduced. LOS ANGELES DISTRICT A few plants are grown by nurserymen in the Los Angeles district to supply stock for filling small orders, but the bulk of the commercial planting stock originates in the lower central Mississippi Valley states. Local nurserymen usually take orders from the growers and have the stock shipped in as needed for planting. OREGON PLANTS A considerable portion of the planting stock used in central California originates in the state of Oregon. The moist climate of late summer and early fall there is favorable to the growing of strawberry plants, and no irrigation is practiced. The hill system of planting is used and the runner plants grow as they will around the mother. After the runners have been dug in the spring, the mother plants are normally left for fruiting. Under this system plants are produced more cheaply than in California. A system of certification is in use in Oregon. Growers who have planted certified or selected stock and comply with specified rules may at the end of the year have their plantings examined by state officers, and if these are found free of virus diseases, particularly "crinkle," the grower is given tags to attach to shipments originating from the inspected plant- ing. Such stock is sold as "certified" plants. MARKETING AND SELLING THE STRAWBERRY CROP A portion of the strawberry crop in all districts of the state is disposed of locally, either direct to customers calling at the strawberry planting or to local merchants, roadside stands, and fruit markets. The berries not disposed of in this manner are shipped to the larger markets of this and other states. In this state, the berries are usually handled through wholesale commission merchants. The fruit is trucked to them daily, usually after picking hours and during the night when air temperatures are coolest, and is available on the wholesale markets the following morn- ing where local retail merchants and chain-store buyers select and pur- chase the berries needed by them for the day. All berries shipped to the market are disposed of each day, the fruit being too perishable to allow for carryover. The commission merchant attempts to secure the highest price commensurate with the quantity of fruit that he has to dispose of. The best berries bring the highest price and it is sometimes necessary to reduce the price appreciably to move the fruit of lowest quality. The The Production of Strawberries in California 61 commission merchant makes a charge for this handling of 10 to 12 per cent of the wholesale price and makes payment direct to the grower after subtracting the commission. The grower is often aided financially by a commission merchant and in return sells his strawberries through him. Marketing associations have been formed in several districts of the state and in some, more than one association exists. The strongest of the groups is the Central California Berry Growers' Association, operating in the central-coast district and handling raspberries and blackberries as well as strawberries. Most of the other associations are either entirely or predominately composed of and managed by Japanese. The main purpose for which these groups are organized seems to be the handling of interstate and outside-the-district shipments, although some assist in the orderly marketing of fruit within the district in which they operate. While the principal function of the association in the past has been selling, some are now handling the purchase of supplies for their grower members and are able to obtain for them a substantial saving. Precooling of the berries before loading into refrigerated rail express cars is practiced in all of the eastern United States shipments and in some of those to the Pacific Northwest and other western states. This desirable practice should be followed wherever facilities are available, and is especially important when shipments are made during warm weather. In the central-coast district of California at the end of each day, the berries for interstate shipment are trucked to a central pre- cooling plant operated by the association and cooled for several hours in special rooms held at a temperature of 34° to 36° Fahrenheit, after which they are loaded into cooled refrigerated express cars for trans- portation across the continent. The temperature inside the car during transit will vary from 40° to 45° and is low enough so that the fruit reaches the New York market in fair condition. After its arrival any decaying or molded berries are usually sorted out before offering for sale on the eastern markets. STRAWBERRY GRADES AND STANDARDS The following extract from the 1937 Agricultural Code of California' applies to strawberries : Strawberries . . . shall be mature but not overripe, free from insect injury which has penetrated or damaged the flesh, and from mold, decay, and damage due to sun, frost, bruises, disease, or other causes. Not more than ten per cent, by weight, of the berries in any one container or bulk 2 Agricultural code, revised to August 27, 1937. Section 793, p. 159-60. Published by the California State Department of Agriculture, Sacramento, California. 1937. 62 California Agricultural Extension Service [Cir. 113 lot, may be below these requirements, but not to exceed one-half of this tolerance shall be allowed for any one cause. Any strawberry which has two-thirds of the surface showing a pink or red color, shall be considered mature. All strawberries shall be in the dry pint basket, containing an interior capacity of approximately thirty-three and six-tenths cubic inches. The United States Department of Agriculture, Bureau of Agricul- tural Economies' has outlined the United States standards for straw- berries, effective November 19, 1934, as follows : U. S. no. 1 shall consist of strawberries of one variety, with the cap (calyx) at- tached, which are firm, not overripe, or undeveloped ; and which are free from mold or decay and from damage caused by dirt, moisture, foreign matter, disease, insects, or mechanical or other means. Each strawberry shall have not less than three-fourths of its surface showing a pink or red color. Unless otherwise specified, the minimum size shall be not less than three-quarters of an inch in diameter. In order to allow for variations other than size incident to proper grading and handling, not more than a total of 10 per cent, by volume, of the strawberries in any container may be below the requirements of this grade, but not more than 5 per cent shall be allowed for defects causing serious damage, and not more than two-fifths of this amount, or 2 per cent shall be allowed for strawberries affected by decay. In addition, not more than 5 per cent, by volume, of the strawberries in any con- tainer, may be below the specified minimum size. U. S. no. 2 shall consist of strawberries which are free from decay and from serious damage caused by dirt, disease, insects, mechanical or other means. Each strawberry shall have not less than one-half of its surface showing a pink or red color. Unless otherwise specified the minimum size shall be not less than five-eighths of an inch in diameter. In order to allow for variations other than size incident to proper grading and handling, not more than a total of 10 per cent, by volume, of the strawberries in any container shall be allowed for defects causing serious damage but not more than 3 per cent shall be allowed for strawberries affected by decay. In addition, not more than 5 per cent, by volume, of the strawberries in any con- tainer may be below the specified minimum size. Unclassified shall consist of strawberries which are not graded in conformity with either of the foregoing grades. Definitions of Terms As used in these grades: "Overripe" means dead ripe, becoming soft, a condition unfit for shipment and necessitating immediate consumption. "Undeveloped" means that the berry has not attained a normal shape and develop- ment due to frost injury, lack of pollination, insect injury, or other causes. "Button" berries are the most common type of this condition. "Damage" means any injury or defect which materially affects the appearance or the edible or shipping quality. 3 United States Department of Agriculture Bureau of Agricultural Economics. U. S. standards for strawberries. Washington, D. C. November 12, 1934. 2 p. (Mimeo.) The Production of Strawberries in California 63 "Serious damage" means any injury or defect which seriously affects the appear- ance or the edible or shipping quality. Soft, badly deformed, badly bruised, decayed or leaky strawberries or strawberries which are caked with dirt or which have less than one-half of the surface showing pink or red color shall be considered as seriously damaged. "Diameter" means the greatest dimension taken at right angles to a straight line running from the stem to the apex. It is unlawful to prepare, transport or sell a deceptive strawberry pack. FREEZING STORAGE OF STRAWBERRIES The storage of strawberries at temperatures below freezing has been practiced in the Pacific Northwest for some time. For the barreled frozen-pack trade the stemmed berries are washed as they come from the field, usually mixed with sugar and placed in large barrels and rapidly frozen at temperatures far below freezing; then stored at temperatures that insure maintenance in a frozen state and held until needed. While frozen strawberries are used by ice-cream manufacturers, bak- ers, fountain operators, and others at seasons of the year when fresh fruit is unavailable or expensive to purchase, the greater proportion of this frozen fruit is used in making strawberry preserves and jams. Under this arrangement, the entire pack need not be preserved as the berries ripen but can be handled at seasons of the year when the manufacturing plant is not busy with the preserving and packing of other products. Frequently the frozen fruit is shipped across the continent and the pre- serves and jams manufactured on the eastern coast. In California at this time (1939), practically none of the crop is handled in the above manner. The price of fresh market strawberries is high enough so that there is no incentive to dispose of the berries for barreling purposes. Quick-freeze strawberries, available in some of the large city markets in California, are mostly put up in the Pacific Northwest. The berries are sliced and sugar added, then they are quickly frozen. They are sold to the general public as a substitute for fresh berries in much the same manner as ice cream is sold. This product compares favorably with the fresh fruit, and its sale seems to be restricted largely by the lack of proper facilities in the grocery and ice-cream retail stores for holding the packaged fruit at correct temperatures. With the development of better facilities for distribution, an increase in consumption is likely, and some of the California crop will probably be used each season for quick-freeze strawberries. 64 California Agricultural Extension Service [Cir. 113 VARIETIES There is no variety now being grown in any of the major strawberry districts of the state that is entirely satisfactory even for the district in which it is grown. None is available that combines all the characters desired in a variety, and growers must resort to the use of those nearest the ideal. Although the strawberry as a fruit is widely adapted, there are probably few fruits in which individual varieties are as exacting in their requirements. The responses of varieties to the duration of the daily light period have been studied by Darrow and Waldo' of the United States Depart- ment of Agriculture, who concluded that the temperature-day-length reponse determines the regional adaptation of a variety. Those that do well in the south grow during the short days of late winter and early spring and need only a short dormant period, if any at all, whereas northern varieties grow very little during the short days and require a low-temperature dormant period before their rest is broken. This would appear to explain why some varieties that do exceptionally well in the northern part of the state fail almost completely when grown in the southern part and vice versa. This daily light factor would not explain, however, the established fact that a variety suitable in one locality may be entirely unsatisfactory in another a few miles away. It may be par- tially explained by the assumption that in addition to the temperature- day-length response there is a direct effect of temperature alone. Further, the type and character of the soil and the diseases and insect pests are also influences that determine the adaptability of a variety to a locality. Some, as for instance the Marshall type, thrive under a variety of climatic and soil conditions and are widely adapted. Other varieties, an example of which is the Nich Ohmer, are specifically adapted and are very exacting in their requirements for normal and satisfactory growth. This variation in response to growing conditions naturally may change the character of growth of the plant or its fruit. In the descriptions of varieties which follow, some consideration must be given these vari- ations ; unquestionably, in some localities the divergence of a character from that described will be appreciable. All of the varieties now used commercially in this state have perfect flowers, that is, functional male and female parts in the same flower; with these, there is no need for planting other varieties to insure cross pollination. There remain, however, a few imperfect-flowered varieties * Darrow, George M., and George F. Waldo, Eesponses of strawberry varieties and species to duration of the daily light period. U. S. D. A. Tech. Bill. 453:1-31. 1934. The Production of Strawberries in California 65 on the eastern markets having only pistils, or female organs ; if one of these is used, it is then necessary to grow nearby a pollen-producing variety which blooms at the same time. The following paragraphs contain brief descriptions of and comments on some of the most important strawberry varieties now being grown in California.^ Marshall Type: Marshall, Banner, Oregon, New Oregon, New Oregon Improved, Oregon Plum. — Differences between varieties of the Marshall type as regards the appearance of the fruit or plant are so slight that for purposes of description here all may be considered as one. The ]\Iarshall is the the oldest variety, and the others appear to be either strains of the original, with little or no variation, or seedlings of it which very closely resemble the parent in major characters. The plant is large and vigorous, has an open crown and erect foliage, and is a moderate runner-plant maker. The fruit is medium to large in size, conic in shape, often rough and irregular in surface. The flesh is moderately firm with the skin soft and partly protected by yellow seeds. The color is deep red with a tendency to remain white on the unexposed side ; the flesh is lighter in color. The appearance is good but becomes dark and poor when overripe or upon standing. The quality is excellent. The Marshall-type berry is very susceptible to the yellows and crinkle diseases, but resistant to Yerticillium wilt, and excess salts in the soil, and moderately resistant to Phytophthora root rot, and seemingly to mites. It does reasonably well on heavy or moderately wet soils. A stand- ard variety, it is the most widely used of all in central and northern California. The most variable character among these so-called ''varieties'^ is pro- duction. Growers in the central-coast district claim the Banner out- produces the Marshall because of its habit of bearing several crops dur- ing the spring, summer, and fall instead of one main spring crop and minor summer crops, as does the Marshall in certain seasons. For this reason, the Banner is preferred in the central-coast district. In the Sac- ramento district, Oregon Plum is used as a trade name under which most of the berries of this type are sold, but there seems to be no founda- tion for its use as the name of a specific variety. Marshall is the name widely used in the San Joaquin Valley for this type of berry. Nich Ohmer. — The plant of Nich Ohmer is medium in size and vigor, has an open, simple crown, and is an abundant producer of runner plants. The leaf blade and petiole are pubescent (hairy) ; the flower ■' A more detailed description of the older varieties may be found in: Hedriek, U. P. The small fruits of New York. p. 355-559. New York (Geneva) Agr. Exp. Sta. Re- port for 1925. 66 California Agricultural Extension Service [Cm. 113 and fruit stem are of medium length in spring and extremely long in summer and fall. The berry is medium to large, conic in shape, and reasonably symmetrical ; the calyx is exceptionally large. The flesh is a little dry and at times puffy, with skin firm and protected by surface seeds. The color is bright glossy red, giving excellent appearance and attractiveness to the fruit. The quality is low and without much char- acter. The production is medium in spring but good in summer and fall. The variety is used principally along the central coast as a summer and fall shipping berry ; it carries well. Because of its resistance to the yellows disease, it has replaced Banner, but it is very susceptible to mites, Yerticillium wilt, alkali, excess soil salts, Phytophthora root rot, and wet soil, and should not be used where any of these troubles are serious. It is moderately susceptible to mildew. The plant is inherently short-lived and made more so by susceptibility to the diverse diseases and troubles affecting it. The variety does poorly on heavy or compact soil. Dorsett. — Recently introduced by the United States Department of Agriculture, Dorsett forms a healthy, vigorous plant with dark-green foliage and very dense crown and is a good runner-plant maker. The flower stems are short, which makes the picking of fruit somewhat diffi- cult. The fruit is medium to large at the beginning of the season but be- comes medium small at the end and may be objectionably small at subse- quent fruiting seasons ; it is conic in shape and of good symmetry. The flesh is firm, with soft skin partially protected by seeds. The color is medium red, lighter than Marshall or Nich Ohmer, with medium-deep- red flesh. The appearance is good and the quality very good except for a little strong flavor at certain seasons of the year. In rich soil, the Dor- sett plants are sometimes too vegetative. Because of the large dense crown, the runner plants should be spaced from 10 to 12 inches apart on the bed, otherwise the growth becomes too dense and the berries do not develop as they should. The variety is moderately susceptible to yellows and Yerticillium wilt. The Dorsett has not been grown sufficiently in all parts of the state to determine the limits of its adaptability. The variety has done well and has given exceedingly high yields in some plantings in the cool Watsonville-Salinas area but only moderate yields in other plantings in the same section. It is, however, doubtful if the berry will reach the popularity in the Watsonville-Salinas district that its high yield might indicate because of the tendency in certain seasons to mature the crop rapidly, reaching a high peak midway in the season and then dropping off sharply. This necessitates the hiring of a large number of extra pickers during the peak and does not allow the operating families to The Production of Strawberries in California 67 do most of the picking as is the case where a more gradual ripening of the crop occurs. It appears to do well in the Los Angeles district but poorly in the interior valleys. Klondike. — The standard variety for southern California, Klondike has good vigor, clean foliage, narrow leaves, and an open crown. The plant is moderate in size and produces an abundance of runner plants. The fruit is of medium size but becomes small at the end of the season ; when plantings are over three years old, the fruit may be too small for commercial markets. It is round conic, sometimes necked. The flesh and skin are firm and of medium-red color. The appearance is dull, the quality medium, the flavor acid. The variety is a good shipper and a heavy producer in spring but has no fall production. It is moderately resistant to yellows, but suscep- tible to Verticillmm wilt. It is adapted to southern climates and is not a satisfactory variety in central or northern California. Blakemore. — Introduced in 1929 by the United States Department of Agriculture, Blakemore forms a healthy, medium-small plant, which produces runner plants freely. The berry is of medium size but becomes small at the end of the crop. It is blunt conic, firm, with light-red skin and flesh, of good appearance and medium quality, an excellent berry for preserving. The variety is a good producer, moderately resistant to yellows, but susceptible to Verticillium wilt and subject to a yellow leaf variegation. It was used to some extent in southern California a few years ago in place of the Klondike but has lost favor there ; it is not suited to central California. Missionary (Carolina). — The plant of Missionary is of medium size and vigor but produces runner plants freely. The berry is of medium size, conic, with medium-firm, medium-dark-red skin and flesh. The flavor is acid, the quality fair. The variety is a moderate producer, mod- erately resistant to yellows. It is used to some extent in southern Cali- fornia along with Klondike but matures later. A southern variety, it is not suited to northern climates. Bedheart. — Introduced by the United States Department of Agri- culture in 1931, Redheart forms a large vigorous plant, with a mod- erately dense crown ; but the production of runner plants is low in most California districts. The berry is large, irregular long conic, with firm flesh, rich dark-red color, which becomes very dark when picked and held ; it is the darkest of all varieties used in the state. The flesh likewise is very dark red. The variety is a good shipper and has high dessert qual- ity, sometimes a little strong ; the flavor is acid and aromatic. It is used extensively in the Pacific Northwest as a canning berry. There is a light 68 California Agricultural Extension Service [Cm. 113 fall production along the coast. It is susceptible to Verticillium wilt and yellows. Narcissa. — Kecently introduced by the United States Department of Agriculture, Narcissa forms a vigorous plant with clean bright foliage, free from mildew or leaf spots. The berry is conic, bright-red in color, of moderately firm flesh and with excellent dessert quality. It is mod- erately large the first picking year but at times becomes objectionably small the second year. Limited trials indicate this variety may have promise along the central coast. There is fair summer and fall produc- tion during favorable seasons. Fairfax. — Another recent introduction of the United States Depart- ment of Agriculture, Fairfax forms smaller and more open-crowned plants than the Dorsett. The fruit is large, of good appearance and ex- cellent quality and firmness. The variety is less productive than the Dorsett and very susceptible to mildew. It is very doubtful if the variety has any commercial promise in California. New Washington (Ruby). — The New Washington originated in the garden of a strawberry grower near Seattle, Washington, about 1928. A variety appearing a short time later under the name of "Ruby" seems to be the same berry. The plant is large and vigorous. The berry is medium to large, rounded, and at times irregular, with very soft skin and flesh. It is very dark red when ripe with a tendency to color un- evenly ; the flesh is lighter. It has a dull appearance when overripe. The quality is good, with some wild aromatic flavor. The variety is a heavy producer with some fall production along the coast, is resistant to Phytophthora root rot and Verticillium wilt, but is susceptible to yellows and mildew. This variety has been grown a little in the central-coast district. It is too soft for interstate shipping and during the hot weather of summer is almost too soft even for local shipment. Because of this softness, it is of doubtful promise in the state. Bellmar. — Another recent introduction by the United States Depart- ment of Agriculture, Bellmar forms a good plant. The berry is large, long conic, with moderately firm flesh and skin and bright red color, darkening some after picking; the flesh is lighter red. The appearance and quality are good. The variety tends to bear a single, heavy, early crop and matures its fruit over a short period of time, which makes it unsatisfactory as a general market berry. It is suggested for trial where a good-quality early berry is desired in central interior valleys. Magoon. — An old variety seldom grown except where soil is heavy and other varieties fail, Magoon is of medium quality and appearance. NortJistar, Fairmore, and Daybreak. — Introduced in 1939 by the United States Department of Agriculture but inadequately tested in California. The Production of Strawberries in California 69 EVERBEARING VARIETIES No everbearing variety has shown sufficient merit to warrant adoption for any extensive commercial planting. They are used at times in door- yard plantings, in small garden plots, or at the higher altitudes where heavy spring frosts occur. If the early crop is frosted out, later crops are produced, and there is not a total loss as might otherwise be the case. Ordinarily everbearers, in contrast with the noneverbearers, will, when set in the spring, bear a heavy crop in the fall of the same year. To main- tain vigor under most California conditions and particularly in south- ern California, new beds should be set each year. Some growers prefer to set early in the season, force the berries as much as possible for fruit production during the year, and replace the planting the next season. It is seldom profitable in any part of the state to allow the old bed to re- main more than two years. Compared with other sorts, total production in the everbearers is usually low. Since many of the noneverbearing varieties produce in the summer and fall months along the central coast and supply the state markets, there is not the demand for everbearers in California that might exist in other states. Rockhill 26 (Bockhill). — Highest in quality of the everbearers now on the market, the Rockhill has berries medium large and of good ap- pearance, with medium firm flesh. The variety is gaining favor in the Los Angeles section, where it is forced heavily the first year. It is re- ported as a good berry in Oregon. Under California conditions, runner plants are seldom produced, and propagation in the state is by splitting apart the crown. Most plants set out here are shipped in from northern states, where a few runners per plant usually develop. Such plants are necessarily expensive and can be obtained in only limited numbers. Mastodon. — The plant of Mastodon has medium good vigor, and is a fair producer of fruit and a moderate producer of runner plants. The berry is large, hollow, moderately firm, and of fair quality. Much of planting stock is infested with mites and should be treated before planting. Gem. — Reported as of some promise in Oregon, Gem appears to be of questionable promise in the central-coast district. New Mammoth (Bed Giant, Shasta Queen). — Reported as success- fully grown in Utah, New Mammoth has a large irregular berry, light color, poor quality, and dry flesh. Limited trials in California indicate that the variety has but little promise in this state. Progressive. — An old everbearer variety grown principally in home gardens. Progressive does best at the higher elevations or in the northern part of the state. 70 California Agricultural Extension Service [Cm. 113 DISEASES AND INSECT PESTS OF THE STRAWBERRY LEAF TROUBLES Leaf Spot. — Tlie disease caused by the fungus Mycosphaerella fragariae is recognized by the small dead spots with brownish-red borders and white centers occurring on the leaves (fig. 21). This disease seldom re- quires spraying in California but should it become serious in a planting, a bordeaux mixture (4-4-50) spray will be helpful. The spray should not be applied after the berries have attained more than half size because Fig. 21. — strawberry leaf spot, usually found but seldom serious in most strawberry districts in California. Late spring rains favor development of the disease, which can be controlled with bordeaux-mixture spray. of the residue deposited upon the fruit. In the central-coast district, the practice of removing all the leaves a month before the beginning of spring growth undoubtedly helps to keep the disease down. Powdery Mildew. — Along the coast during seasons or periods of cool or damp and foggy weather, powdery mildew, caused by the fungus, Sphaerotheca Jiumuli, may be the cause of considerable injury to the foliage and fruit (fig. 22). Mildew-affected leaves curl inward and be- come reddish in color on the curled part. Burning of the edge of the leaf is not uncommon. No thoroughly satisfactory means of control is known. Sulfur is likely to cause a burn if the temperature reaches 80° Fahren- heit and is therefore unsafe to use at the season of the year when mildew is the most destructive. If the disease has been serious in the planting The Production of Strawberries in California 71 during the previous year, a dormant-strength lime-sulfur spray just before foliage begins to grow in the spring should be helpful in destroy- ing any holdover. The surface of the bed and the furrow, as well as the foliage, should be thoroughly wetted with the spray. Chlorosis. — When strawberries are set on land having excess lime in the subsoil, they often become extremely chlorotic. The green gradually and evenly fades from the leaves, and the plants become almost white in extreme cases. The yellowing from this cause should not be confused Fig. 22. — Strawberry leaves affected with powdery mildew. The curled surface is usually purpled or burnt. Mildew is most serious along the coast during damp foggy weather of summer. There is considerable variation in varietal suscepti- bility. Lower left, a normal leaf. with the disease called "yellows." No satisfactory method of combating this trouble has been evolved for strawberries, and land known to con- tain excess lime or marl should be avoided. In mild cases, the incorpora- tion of sulfur into the soil may help somewhat. Leaf Variegation, or Gold Disease. — A condition resembling chlorosis in many respects occurs frequently in the Blakemore variety and occa- sionally in a few others. The fading of the leaves is most pronounced in spring or early summer and tends to disappear during the warm weather of summer but may reappear again as the cool weather of fall advances. The cause of the disease is unknown but seems to be associated with the genetical constitution of the plant. Some strains of the Blakemore va- riety are reported to be relatively free of the trouble. 72 California Agricultural Extension Service [Cir. 113 Red Spider, or Two-spotted Mite. — Of all the pests affecting the straw- berry, red spider {Tetranychus spp.) is one of the most serious in the spring and early summer, the most favorable seasons for attack. The red spider is very small and has a yellow body with two or more brown spots on the back. Silvering of the foliage and the production of web on the underside of the leaves are signs of this pest. If not checked when heavy infestation occurs, the red spider rapidly stunts the plant and no recov- ery occurs until it is controlled. A highly refined oil emulsion diluted with water to make a 1 to 1% per cent mixture and with a satisfactory spreader, when applied under high pressure (350-450 pounds), with care to wet the underside of all leaves, has proved an effective spray against red spider. When properly done, one spraying is usually sufficient ; if not, a second should be ap- plied 2 to 3 weeks later. Giving the plants an abundance of water when red spiders appear is helpful ; frequently thorough wetting of the straw- berry bed for a few irrigations will keep the pest under control. In the central-coast district, some growers prefer to give an oil-emul- sion spray just after the removal of the tops and before growth has started, but there is some doubt about the justification for this spray. If red spiders have been numerous on the plants at the end of the previous growing season or are so at the time of topping, the spray may be of value. But if they have not been of concern previous to topping, spray- ing for them alone seems unjustified. During years of heavy red-spider infestation — and these do not occur regularly — later spraying is usually necessary to control the pest even though the early spray has been ap- plied. Consequently the early spray as a regular procedure is not recom- mended. Sulfur should not be used on strawberries later than early spring because of the severe foliage burn that it is likely to cause during the warm weather of summer. Strawberry Aphid. — A small and delicate, pale, yellow-green aphid, Capitophorus fragaefolii, is frequently found in large numbers on strawberries. During the fall and winter months, the aphid propagates on the underside of the mature leaves ; but in the spring and summer, it is usually found on the young leaves emerging from the crown and on the succulent leaf stems. Nicotine sulfate solution containing 40 per cent nicotine, as in Blackleaf 40, added at the rate of % pint to 100 gallons of water plus 1 gallon of summer oil emulsion, is an effective spray. Lib- eral application of 4 per cent nicotine-lime dust (no. 10 nicotine dust) will control the aphid if temperatures are moderately high. Dusting, however, should not be attempted when the fruit is ripening since the coat of dust deposited on the fruit will remain after picking. This aphid transmits crinkle and the destructive yellows disease. The Production of Strawberries in California 73 Leaf Beetle, or Strawberry Rootworm. — Numerous small, elongated, irregular holes (fig. 23) are eaten in the leaves by a small brown beetle, Paria canella, with black markings on the upper side and averaging % inch in length. The larvae (see key, p. 86) are small and white, have three pairs of legs, and feed on the roots. It is a serious pest in the Sacra- mento district and is becoming one in Alameda and Santa Clara coun- Fig. 23. — Leaf -beetle (Paria canella) injury to strawberry leaves caused by feeding of adult beetles. Holes are usually slightly elongated and between the veins of the leaf. Fluosilicates applied in fall after fruit is off give some control. ties. Old fields should be destroyed several months before the setting of new fields, and new plantings should not be set near old heavily infested ones. The effect of this insect on strawberry roots is discussed on page 86. CROWN TROUBLES Crown Rot. — The gray-mold fungus, Botrytis cinerea, is frequently re- sponsible for a rotting of the leaf petioles and fruit stems at the crown of the plant. As the rot progresses upward, the stems collapse, and gray mold may appear on the browned tissue if the humidity is relatively high. The disease becomes serious during prolonged rainy periods or continued foggy weather and is particularly destructive in the Nich Ohmer variety. An ammoniacal solution of copper carbonate sprayed on the crown of the plants is helpful in controlling the disease and, un- like bordeaux mixture, does not leave a residue upon the fruit. The spray may be prepared by adding 6 ounces of copper carbonate in suffi- cient ammonia to dissolve it — usually about 3 pints of 26° Baume — and 74 California Agricultural Extension Service [Cm. 113 adding to this 50 gallons of water. The spray will not hold its strength, and must be made up fresh each time it is used. Rot of the berry caused by this same fungus is discussed on page 87. Another crown rot, caused by the fungus Sclerotinia sclerotiorum, is sometimes troublesome when wet weather occurs after spring growth has begun. The crown when affected turns a straw color, unlike the brown of the gray-mold disease, and all parts collapse, with death of the crown the usual result. Small, irregular, hard, dark bodies (sclerotia) are usually found in the decaying tissue. The same spray as recom- mended for gray mold may be used; but seldom are sufficient plants affected to make spraying necessary. Strawberry Dwarf, or Crimp. — A disease caused by the nematode Aphelenchoides fragariae is occasionally found in California in straw- berry plantings, the stock of which originated in the southern states where the disease is common. Diseased plants become dwarfed and have small narrow leaves, usually crimped and cupped and darker green in color than normal. No control is known other than the removal and dis- carding of diseased plants. Propagating stock should not be selected from plantings where this disease exists. Cyclamen Mite. — An extremely serious pest, minute in size and not readily seen without the aid of a hand lens, the cyclamen mite, Tarsone- mus pallidus, is responsible for the early failure of many plantings in the central-coast district and is a factor in the production of strawberries in the Los Angeles district. Mite-infested plants show varied symptoms dependent in part upon the degree of infestation. When severe, the center leaves are dwarfed, peculiarly wrinkled with fluted edges (^g. 24) and often bronzed or reddened at the base, with the blade a pale, dirty-yellow-green. The mite lives and multiplies in the young unfold- ing leaves of the crown (fig. 25), where it is protected from sprays and fumigants ; and consequently no control of the pest on infested plants in the field is known. Propagating stock may be freed of the mites by immersion for a period of 1/2 hour in water held at a temperature of 110° Fahrenheit or by hold- ing in a water-saturated atmosphere at 110° for 1 hour. The latter method causes less injury to the plants. Growers are warned not to use homemade apparatus for heat treatments without adequate and proper heat control ; for a very slight variation in temperature may result in injury to the plant or failure to kill the mite." It is advisable to treat all " For further details on this treatment see : Smith, Leslie M., and Earl V. Gold- smith. The cyclamen mite, Tarsonemus pallidus, and its control on field strawberries. Hilgardia vol. 10, no. 3, p. 53-94. A copy of this may be obtained by writing the Publications Office, College of Agriculture, Berkeley, California. The Production of Strawberries in California 75 Fig. 24. — Strawberry plants showing advanced symptoms of mite injury. This serious pest spreads rapidly and has ruined many strawberry plantings. Control lies in the use of stock disinfested by heat treatment. Marshall-type varieties ordinarily escape injury. Upper, Nich Ohmer variety; lower, Boquet. (From Hilgardia vol. 10, no. 3.) 76 California Agricultural Extension Service [Cir. 113 the planting stock set out in the coastal district where the pest is serious. Infestation may result from neighboring old fields but should be appre- ciably less than would occur if the planting stock was infested when set out. If the new planting, set with heat-treated stock, is isolated and precautions taken to keep out workers and implements or equipment of , A 1 JKHJIlSillife'^ -^Y -. ^^^^' m ■ ■ ■"■■ l« * n§|i^S ^'N ♦ .,.i jHBWppH|K| 1^^ ■ ^n^^Mff^^Bj^^^^^^^^ GLi^ ■hi K- Fig. 25. — Upper surface of a young leaflet of Nich Ohmer strawberry which has been opened to show mites and eggs at the base of the leaflet. (From Hil- gardia vol. 10, no. 3.) any kind that might carry the mites from infested fields, the chances are good that it will escape serious mite injury during its normal life. Occasionally natural predators reduce the mite population tremen- dously, but seldom can this means of control be relied upon to keep the pest in check. Some varieties, examples of which are the Marshall-type plants, have consistently shown greater freedom from this pest in the field than others. In a few instances, however, heavy infestation has been observed The Production of Strawberries in California 77 in the Banner, which indicates perhaps that the Marshall-type varieties are ordinarily resistant but may become susceptible to certain strains of the mite. Likewise, if the mite is forced to feed upon the variety because of a scarcity of preferred food, it may become adapted and eventually thrive on Marshall types. Strawberry Crown Moth, or Crown Borer. — The white larvae of the Fig. 26. — Caterpillar of the strawberry crown moth in a raspberry cane. The borer is normally serious only in plants on high or gravelly ground that receives inadequate moisture. (After Leslie M. Smith; from Ext. Cir. 87.) strawberry crown moth, Synanthedon rutilans (fig. 26), measuring % inch or less in length, bores into the strawberry crown and causes the plant to wilt and die. The borer works principally on plants allowed to suffer from lack of water, hence is serious on gravel or other soils where sufficient soil moisture is difficult to maintain and on high spots due to poor leveling. The remedies suggested are to remove and burn infested 78 California Agricultural Extension Service [Cir. 113 plants, keep the planting well irrigated, avoid gravelly soil, and do a good job of leveling. The key on page 86 may be helpful in distinguish- ing this borer from other larvae found on strawberries. Strawherry Root Aphid. — Dooryard and occasionalh^ field straw- berry plants become infested with the strawberry root aphid. Aphis for- hesi, a small black or greenish-black insect, which covers at times tlie Fig. 27. — Spittle-bug injury and Avhite foam in which the bug lives. Early damage is sometimes alarming on plants but is not serious since in California the bug soon disap- pears and does not return to strawberries. roots, crown, and base of the petioles of the strawberry plant. This aphid appears to be almost always attended by ants, the latter building mounds or cases of soil over the plant crown to protect the aphid. Control lies in saturating the crown of the plant with a 40 per cent solution of nicotine sulfate diluted 1 to 800, re-treating in 2 or 3 weeks if necessary, and eradicating the ants."^ Spittle Bug. — Froth forming in the crown of the plant indicates that the spittle bug, Philaenus spiimarius, is active, and some stunting of the plant may be a temporary result (fig. 27) . Observations to date indicate the bug enters the state on plants brought in from the Pacific Northwest and develops when the plants are set out in California. When the bug matures, it leaves the strawberry and apparently does not return to it. ^ For methods of controlling ants, see : Eckert, J. E., and Arnold Mallis. Ants and their control in California. California Agr. Exp. Sta. Cir. 342:1-37. 1937. The Production of Strawberries in California 79 No permanent injury may be expected and no control measure is ordi- narily necessary. Nicotine dust or hydrated lime will kill the bug and reduce the amount of temporary injury. TROUBLES AFFECTING THE GENERAL VIGOR OF THE PLANT Yellows, or Xanthosis. — Yellows is a virus disease found in nearly all parts of the state where the Marshall-type varieties are grown. The most severe losses occasioned by this degeneration trouble occur in the cen- tral-coast district. The plants lose vigor, become stunted, and develop small, yellow-margined leaves (fig. 28). All the daughter plants from an affected mother plant have the disease. The yield of fruit is greatly Fig. 28. — Banner strawberry showing typical yellows, or xanthosis, symptoms, a serious virus disease that is spread by aphids. Note the small, wrinkled, yellow-margined leaves. The use of disease-free stock and isolation of the plantings are the best means of control. (From the Journal of Agri- cultural Eesearch vol. 35, no. 12.) reduced and does not attain full size and quality. The plants are not killed but never recover, although they may show temporary improve- ment during the hot weather of summer. When fields become seriously diseased, they are usually abandoned. The disease is carried from infected to healthy plants by the straw- berry aphid, which tends to increase in numbers enormously during the winter and early spring months and then decreases rapidly and almost entirely disappears by late spring or early summer. Because of this 80 California Agricultural Extension Service [Cir. 113 peculiarity in the life history of the aphid, growers may profit by plant- ing late and thereby escape the aphid infestation and the danger of in- fection by yellows. Experience indicates that plants set after the middle of April are usually unaffected by the disease the first year and remain healthy longer than plants set early in the season. Isolating the planting at least 2 or 3 miles from other strawberries and the use of plants certi- fied free of the virus diseases are the most satisfactory means of combat- ing this trouble in sections where it exists. Once the plant has become infected with yellows, there is no known means of cure or chance for recovery, and such plants, together with any runner plants from them, should be removed and destroyed as soon as recognized. In new plantings it is important the roguing be done the first growing season. If the plants become heavily infected the fol- lowing winter, roguing the second year is impractical because of the numbers involved. The Marshall-type varieties, including Marshall, Banner, New Oregon, and Oregon Plum, are very susceptible to yellows. Dorsett and Ruby or New Washington are moderately susceptible. Nich Ohmer, Klondike, and Missionary show considerable resistance. Crinkle. — The disease known as "crinkle" is caused by a virus and occurs principally in plants shipped into California from the north. It has never been observed on stock grown in the commercial propagating districts of this state nor has it appeared to spread appreciably from one plant to another in California plantings where it was introduced. As in yellows, the strawberry aphid is the agent of spread. Crinkling of the foliage is the principal symptom of the disease. Stunting is less severe than in yellows and there is no marginal yellowing of the leaves, but the latter may become flecked with small yellow spots, irregularly spaced over the leaf surface (fig. 29). Care should be taken that only disease- free plants are set out. Rogue out any plants that exhibit the disease later. All runner plants from an affected mother plant have the disease. Verticillium Wilt. — Promising to become one of the most serious dis- eases affecting strawberries in California, Verticillium wilt, caused by the fungus Verticillium alhoatrum, is widely scattered throughout the state, almost always occurring in berries planted on land cropped at some previous time to either tomatoes or potatoes. The outer leaves of affected plants wither, turn brovm, and die ; often the entire plant dies. Frequently side shoots develop from a withering crown. Large spots of dying plants may develop in a strawberry planting and partially ruin it. Seldom does the disease cause serious injury during the spring months ; but with the onset of hot weather of summer, plants begin to wilt and die and continue dying until late fall. There is no practical control for this disease. The greatest care should The Production of Strawberries in California 81 be exercised in selecting a site for strawberries, to obtain land that has never been previously cropped to either tomatoes or potatoes. While these two crops are not always affected with the Verticillium fungus, they usually are, and there is no simple method of determining whether or not they may have been. It is a safer practice always to avoid tomato or potato land for planting strawberries. Most strawberry varieties used '^m Fig. 29. — Leaves of Marshall strawberry showing typical symptoms of the crinkle disease. Note wavy, crinkled leaflets with small, scattered, yellowish areas. Leaves on right are normal. The disease ordinarily is not serious in Cali- fornia except on some of the stock originating in the Northwest. in California are susceptible to the disease. Only the Marshall type and Ruby or New Washington have demonstrated sufficient resistance that they may be used in V erticillium-mf ested soil with any assurance of suc- cess. If a planting is unknowingly set in infested soil and plants are lost, some growers find it practical to reset the vacant spots with locally grown runner plants late in the fall, usually November. Such plants will bear some crop the coming season and a portion will usually survive the dis- ease.^ Heavy Grading of Soil. — When strawberries are planted on uneven ground and leveling is necessary, heavy cuts are sometimes made, with the result that the strawberries planted on this heavily cut land fail to make satisfactory growth. There is a general lack of vigor and sparseness of growth without definite disease symptoms in either the foliage or root *For further details concerning this disease, see: Thomas, Harold E. Verticil- lium wilt of strawberries. California Agr. Exp. Sta. Bui. 530:1-16. 1932. 82 California Agricultural Extension Service [Cir. ii3 system. Strawberries appear to be more susceptible than many other crops to this trouble, and precautions should be taken in most soils to avoid making grade cuts of more than 2 or 3 inches. Some relief from the effects of heavy grading may be had by the application of fertilizer, particularly nitrogenous, to the affected areas. (See discussion of this topic under "Preparation of the Land before Planting," p. 33.) Alkali and Other Excess Salts. — The accumulation in the soil of alkali or other salts in excess is detrimental to the growth of the plant ; and the severity of injury will depend upon the concentration and character of the accumulations. Frequently observed symptoms are burning at the edge of the leaves, chlorotic and weak plants, black and partially dead roots, and generally devitalized plants. Common table salt when in ex- cess causes a burn at the edge of the leaves, while the black-alkali salts produce a chlorotic effect and general weakening. Knowing the nature of the salt present in excess is usually advantageous in the consideration of remedial measures. In some instances, leaching will help if high- quality water is available and adequate drainage can be established or if the soil is sufficiently deep to allow washing the accumulations into lower strata. In the irrigation of soils possessing more than the ordinary amount of salts or alkali, the quality of the water used is important. Although the land may have more than is desirable of these excesses, if the water used in irrigation is reasonably free of them no serious damage may result ; on the other hand, if the salts or alkali in the soil are near the tolerance limit for strawberries and poor water is applied, the re- sult may be disastrous. The University of California maintains a laboratory which examines soil and water for the presence of alkali and injurious salts, and it is advisable, if these substances are suspected, that prospective growers avail themselves of this service. The farm advisor or county agent can advise growers on the method of sampling the soil and water and give directions for mailing. Nonadaptation of Varieties. — Frequently varieties are planted that are not adapted to the district in which they are set, and usually after the first growing season they do very poorly. This is true of the majority of strawberry varieties used in the eastern part of the United States when planted in California. No particular disease symptoms are in evi- dence, but a general lack of vigor is noted. Several factors contribute to this nonadaptation of varieties, one of which is the temperature-day- length response referred to in the discussion on page 64. Another factor is the mild winter, when insufficient frost or cold weather occurs to break the rest period satisfactorily. In localities free of frost such varieties as Marshall, Banner, Oregon, and others requiring cold to break the The Production of Strawberries in California 83 rest often do very poorly in the spring of the year, produce inferior- quality fruit, and make unsatisfactory yields. Obviously the remedy for nonadaptation lies in the use of varieties suited to the district. Untested or new varieties in any district should be used with caution until their response has been determined. ROOT TROUBLES Brown-Core Boot-Bot, Bed Stele, or Phytophthora Boot-Bot. — Although the trouble has probably occurred in the state for several years and has been responsible for an undetermined portion of the spring dying of strawberry plants, the cause of brown-core root-rot in this state was not determined until 1934, when it was found to be a fungus belonging to the genus Phytophthora. The trouble is easily recognized by stripping the root with the thumb nail and exposing the core, which if diseased will exhibit a deep-reddish-brown color (fig. 30). All or only a few of the roots on a plant may show this symptom. At first the cortex or outer covering of the root remains white and from external appearances there is often no evidence of the disease. Later the cortex dies and blackens and the entire root decays. The disease is active during the cold, wet winter months and is greatly favored by excessive soil moisture occa- sioned by lack of drainage or high rainfall. The first evidence of the disease in the field may be the failure of some plants to start growth in the spring when healthy plants normally start. At other times, probably when late infection occurs, the plants may start and grow normally in the spring and suddenly collapse when a little warm weather occurs. This is more noticeable in Marshall type plants than in other varieties. Diseased plants do not always die and may exhibit some recovery by June or July if the soil is not kept too wet, but commercially such plants are valueless, and usually affected areas are abandoned. The disease spreads in the strawberry bed from sick to healthy plants ; at times the spread is rapid. The principal source of the disease appears to be infected planting stock. This necessitates caution on the part of the purchaser in accepting plants from dealers or growers of such stock. When a field is known to be infected, thorough drainage, even though artificial means have to be resorted to, should help to decrease the severity of the disease. No other control measures are known. Black-Boot. — Plants affected with black-root gradually fail, wither, and die. While some blackening of roots is the normal consequence of age, the condition known as "black-root" is a more extreme and aggra- vated case of blackening, with decay and breakdown of root tissue, the latter often occurring in isolated areas in the root system. The cortex uf the root is the first to turn black, but eventually the entire root and 84 California Agricultural Extension Service [Cir. 113 the whole root system blacken and die. At this stage the plant does not differ in appearance from that killed by the Phytophthora root-rot de- scribed above. The black-root dying of plants occurs in most of the strawberry-growing areas of California and normally takes place during Fig. 30. — Strawberry root with half of the cortex removed to show the brown core characteristic of brown- core root-rot (enlarged). The disease may be serious where land is wet and poorly drained. Avoid planting in- fected stock. the spring or early summer but may occur at any season of the year. The cause of the trouble is usually difficult to determine with any certainty, but apparently there are several factors which contribute to this con- dition. The fungus Bhizoctonia solani is thought to be involved by some investigators. Various other fungi are often associated with the trouble and may in some cases be responsible. Alkali, excess salts, or unbalanced nutrition are other influences that induce blackening of the roots. The varied nature of the cause eliminates the feasibility of suggesting any The Production of Strawberries in California 85 single control measure for this trouble. It is advisable that land known to cause the serious blackening of strawberry roots be avoided. Oak-Root Fungus. — The disease caused by the fungus Armillaria mellea, popularly known as "oak-root fungus" in California, is occa- sionally found in strawberry plantings set on old orchard land where the disease previously existed in the orchard trees, or on land recently cleared of infected native growth. Affected plants turn a reddish-yellow color, then wilt and die. The characteristic fan-shaped sheets of fungus growth are found in the crown tissue of diseased plants. The latter should be dug and burned as soon as discovered. Seldom is the chemical sterilization of the soil feasible or necessary in strawberry plantings. Boot-Knot Nematode. — Strawberries are less seriously affected by the root-knot nematode, Heterodera marioni, than many other plants, and seldom is it of much economic importance in strawberry culture in California. Small, rounded, irregular, fleshy swellings form on the roots. Nematode-infested plants should not be planted on land free of this pest, and soil known to be heavily infested should be avoided for straw- berry culture. Plants should not be propagated on infested soil. Affected plants are usually condemned by the county agricultural inspectors and should not be shipped by the propagators. Weevils, or Snout Beetles. — The adults of several species of Brachy- rhinus may eat the edges of the leaves but seldom is such injury serious. The larvae of the different species vary in length from % to % inch and appear as white worms with curved bodies and brown heads and without legs, which characters tend to distinguish the Brachyrhinus weevils from other white worms found in strawberry plantings (see key, p. 86) . They feed on strawberry roots and cause appreciable damage at times. Infes- tations appear as circular stunted areas in the planting, and the spread is uniform from these centers of infestation. Control lies in the use of poisoned bait such as the commercial dried-apple bait (Go West) or homemade baits prepared according to the following formulas. BAIT I 1 lbs. cull or low-grade raisins soaked in 1 qt. water for 12 hours 1 lb. sodium fluosilicate mixed with 10 lbs. bran and then mixed with the raisins and run through a meat grinder BAIT II 4 oz. arsenic trioxide mixed with 5 lbs. bran 1 pt. water added to 1 pt. of molasses or 1 lb. of sugar, this mixed with the bran and arsenic; more water may be added if necessary to make a dry mash 86 California Agricultural Extension Service [Cm. 113 BAIT ni 10 per cent by weight arsenous oxide (AsgOs) 45 per cent by weight bran 45 per cent by weight dried apple pulp Mix and grind through a meat chopper; add water to make a crumbly mass The bait should be broadcast or placed in the crowns of the plants at a time when no fruit is being picked and when there will be no danger of depositing the poisoned bait on maturing berries. Fifty pounds of bait will usually treat an acre. Strawberry Eootworm, or Leaf Beetle. — The larvae of the leaf beetle, Paria canella, measure Ys inch in length and have 3 pairs of legs. (See key at bottom of page.) They feed on strawberry roots from about April 1 to June 15. Considerable damage is often reported. Some relief from the pest may be had by dusting the plants with sodium fluosilicate late in the fall to destroy the adult or beetle form of the insect, which feeds on the foliage. Fluosilicate cannot be used when berries are being harvested because of the danger of poisoning the fruit. (See discussion of this pest under "Leaf Troubles," p. 73.) White Grubs, or June Beetles. — White grubs, which are the larvae of the adult June beetles, occasionally attack strawberries when grown on old sod land not previously cropped to cultivated plants, or on old orchard land. Because of their large size (sometimes 3 inches in length) they devour enormous quantities of plant material. Two and three years are required to reach maturity, and it is therefore advisable to plant sod land "where grubs occur to a cultivated row crop for two years before planting strawberries. KEY FOR DISTINGUISHING WHITE WORMS OR LARVAE OF BEETLES I. With three pairs of legs A. Very small — % in. long; feed on rootlets Strawberry rootworm, Paria canella B. Large — V2 to 1 in. long; feed inside crown Strawberry crown borer, Synanthedon rutilans C- Very large — 1 to 3 in. long, body curved; feed on main roots. . .White grubs II. Without three pairs of legs A. Head white or cream color Fuller's rose weevil, Pantomorus godmani B. Head brown 1. Small — % in. long Brachyrhinus ovatus or Geoderces spp. 2. Medium — ^ in. long B. rugosostriatus 3. Large — % in. long B. sulcatus Wireworms. — Wireworms are the larvae of click beetles. The common injurious forms are about 1 inch long and, as the name suggests, have smooth, round, elongated bodies. The color varies from yellow to dark The Production of Strawberries in California 87 brown and is usually shiny. The worms feed on the strawberry roots and at times, particularly in light sandy soils, cause damage. Satisfactory control measures have not been developed. Clean cultivation and crop rotation are helpful. Planting small potatoes in infested soil to trap the worms and later removing and destroying the tubers, are reported as a partially successful method of control. Garden Centipede. — The adult garden centipedes, Scutigerella im- % 1 J' f f >-««m 4 I^M Fig. 31. — Centipede injury on a runner plant : the rootlets are almost entirely destroyed and runner plants fail to root. Control lies in the treatment of the soil with carbon disulfide emulsion. maculata, are very small, white centipedelike animals, approximately 1/4 inch long. They feed upon the strawberry roots, particularly the young tender roots of the daughter plants, and when a heavy infestation occurs, the runner plants may be entirely prevented from rooting (fig. 31). The trouble is serious in certain heavy soils that do not dry out sufficiently in summer to kill the centipede. Control consists in the spot treatment of affected areas by the application of carbon disulfide (bi- sulphide) emulsion diluted 1 to 300 with water and applied at the rate of 5 gallons per square yard. The plants are not injured by this treat- ment. TROUBLES AFFECTING THE FRUIT OR BLOSSOM Gray-Mold Rot. — The gray-mold fungus Botrytis cinerea, the same that causes crown rot, appears to be the principal cause of fruit decay in California strawberries. The rot starts as a small, light-gray-brown 88 California Agricultural Extension Service l^^^- n^ spot, soft and almost watery but not leaky, then spreads rapidly and soon involves the v^hole fruit, v^hich darkens in color. If in a moist atmosphere, gray mold quickly covers the berry, giving the disease its common name. In the field, green as v^ell as ripe fruit is attacked, and during and after rainy v^eather, the mold has at times rotted more than 50 per cent of the berries remaining on the plant. In a cluster, infection spreads from diseased to adjoining healthy fruit whether ripe or green. Because of this and as a sanitary precaution, growers at each picking usually require pickers to remove from the plant and drop in the furrow all rotted or rotting berries. Fruit with even a small spot should be thrown out, for if placed in the basket it will decay and cause rot in the good berries. Sanitary measures afford the only known means of lessen- ing the incidence of the trouble in the field. If the weather is dry, little trouble may be expected from this mold. Other Fruit Rots. — Fruit rots of less importance than gray mold are occasionally found affecting strawberries. No control for these, other than ordinary sanitation and care in picking to prevent breaking the skin and bruising the fruit, has been suggested. Powdery Mildew. — Mildew frequently affects the green and ripening fruit as well as the foliage. The white powdery masses of spores may in extreme cases cover the fruit as though it had been dipped in flour. Normal growth and development of red color at ripening time is pre- vented and the berry is of no value. Control is given under "Leaf Troubles," page 70. Western Flower Thrips. — A tiny, pale-yellow to orange or light- brownish-yellow thrips, Frankliniella occidentalis, less than % inch long, frequents strawberry blossoms, often in large numbers, and feeds on and destroys the pistils of the flower. The result is gnarled, ill-shaped fruit (^g. 32). If large populations are found in the blossoms when tested by beating the flowers against the palm of the hand, control is desirable. This may be effected by applying a spray made up of 2 gallons of a highly refined commercial oil emulsion plus % pint of 40 per cent nicotine sulfate in 100 gallons of water, with a suitable spreader added to the spray mixture. Pyrethrum extract could be substituted for the above spray, in which case the manufacturer's directions should be followed. Cyclamen Mite. — When heavy infestations of cyclamen mite, Tarsone- mus pallidus, occur, the blossoms are usually severely injured, turn brown, and fail to set fruit. If less severely injured, deformed fruit may result. See page 74, where the effect of this pest on the crown is discussed. Deformed Berries, Summer Sterility, Nuhhins. — Improperly devel- The Production of Strawberries in California 89 oped, irregular, deformed, gnarled, and twisted berries frequently occur in the Nich Ohmer and other varieties during summer months (fig. 32). Infrequently, similar fruit is formed at other seasons. The berry may develop normally only on one side, the other side becoming dry and seedy ; or the tip end may fail to grow, which may result in a button type of fruit if the injury is severe, or if only mild in a hard seedy tip. Among the causes supposed to contribute to the deformity are (1) fail- rig. 32. — Button or nubbin berries, the result of improper pollination, thrips, mites, or pistil sterility. ure to pollinate properly, (2) thrips or mite injury, and (3) a functional sterility inherent in some varieties and apparently induced at flower- bud formation. Combinations of these troubles often cause deformed berries but the effects of each are not readily separated. The failure to pollinate usually happens when blossoming occurs dur- ing rainy or cold weather, for then insects are not present to visit the flowers and distribute the pollen. Any condition that prevents insects from working in the flowers at blossoming time usually results in a failure to pollinate properly and, in turn, in partially deformed berries. A heavy population of thrips or mites at the blossoming seasons may so injure the flowers that twisted, ill-shaped berries result. For control of these insects, see pages 74 and 88. Weather conditions and the nutrition afforded the plants appear to contribute to the summer-sterility type of deformity, but no means are known by which this trouble may be corrected. 90 California Agricultural Extension Service [Cir. 113 CALIFORNIA TRENDS AND OUTLOOK The trend in total acreage devoted to strawberries in the state has been upvrard ; in relatively few years has the acreage dropped below that of the previous year (table 3). Whether or not the trend will continue upward will probably depend on economic conditions. An upswing with higher price levels would encourage an increase in acreage, whereas lowering price levels would discourage any increase. Any year in which strawberries bring a good price is usually followed by increased acreage for the next year or two, although the increase may not be justified economically. The strawberry acreage did not diminish during the years of the de- pression and low prices ; possibly this fact is indicative of the position in which the people of the state hold the strawberry among the fruits produced in California. The fact that the strawberry is the first fruit to ripen in the spring is partially responsible for its popularity, but the high dessert quality of the berry is undoubtedly its true bid for favor. There seems little likelihood that the per-capita consumption of fresh market strawberries in this state will diminish. The bulk of the crop is disposed of before competition with other fruits becomes keen, which is likely to continue to be the case. The part of the crop produced during the summer and fall months does compete more actively with other fruits, and hence the amount of strawberries consumed by the public during these months will probably never be very great. There is a portion of the early spring when the strawberry is consumed with avidity, but as this season passes and the hot summer months approach, the eagerness of appetite for the com- modity wanes and the demand shrinks ; then regardless of the luscious- ness of the berries offered for sale or the lowness of the price, the original demand cannot be revived. This lack of demand for off-season straw- berries limits the amount of fruit from fall and everbearing varieties that can be disposed of on California markets. Probably these markets could be expanded somewhat if a higher-quality fall berry with better holding qualities were available, but it is doubtful whether any consider- able increase in fall production could be advantageously disposed of on California markets, even though the berry were improved. Many of the principal markets in the United States are sparsely sup- plied with strawberries during the late summer and fall months, but the demand for this commodity on these markets at prices attractive to Cali- fornia growers is insufficient to warrant shipping to them, partly be- cause of off-season reluctance to buy and partly because of the high price at which the berries must sell in order that express and handling The Production of Strawberries in California 91 charges may be met, in addition to the return that the grower receives. The retail price on the eastern market is often in excess of 20 cents per pint basket ; and when other fruit is available, proportionately less in price, most consumers cannot be expected to purchase strawberries. Consequently only hotels and individuals with high incomes ordinarily buy the commodity. With this limited consumption, there seems little likelihood that any important increase in the demand for California strawberries by eastern markets can be expected. The larger markets of the western and midwestern states offer some possibilities for disposing of limited quantities of late-summer and fall berries. To these the express rates are less than to the eastern markets, and the time required to reach them is also less, so that the fruit arrives in better condition. Whenever a high-quality, fall shipping berry can be placed on the market, these points offer outlets for a portion of the crop. On the other hand, with improvement in facilities for handling small-package quick-freeze strawberries in the retail trade, the oppor- tunity for disposing of high-priced fresh berries during the summer and fall period is lessened. The future situation for fall-produced berries cannot be predicted at this time. Probably California cannot seriously compete with the Pacific North- west in either small-package quick-freeze or in barreled frozen-pack strawberries, because of the higher costs of production in this state. The low labor and land costs in Washington and Oregon, coupled with the fact that ordinarily growers there do not irrigate, materially favors re- duced costs compared with those of California. In addition, the quality of the berries grown in California, partly because of the varieties used, is not considered as desirable for preserving purposes. Practically no control, other than the returns to the grower, is exer- cised in this state over the quantity of strawberries placed on the market during the spring months. This economic control has, however, been re- sponsible for creating markets in neighboring western states and thus producing outlets for surplus berries and bolstering up sagging prices during years of high yield or sharp production peaks. While a few berries are preserved by local processors, the quantity handled is in- sufficient to affect the market price ; and because the large preserving companies dislike certain varieties of California strawberries, there seems little likelihood that any sizeable outlet in this field can be de- veloped to care for surplus fruit. In the central part of the state, the development of a control for de- structive diseases and insect pests would unquestionably cause an in- crease in acreage and place the industry on a much more economical and substantial basis. The only opportunity for such control, however, ap- 92 California Agricultural Extension Service [Cm. 113 pears to lie in the development of varieties that are resistant and at the same time better adapted commercially. The University of California has for some time had in progress a program designed to create such varieties, and it appears likely that satisfactory new varieties can be developed by the use of modern breeding methods. The outlook for the strawberry in California is promising, but no immediate large increase in acreage is justified. A small and gradual increase could be satisfactorily handled as long as market prices main- tain about their present level. ACKNOWLEDGMENTS The author wishes to express his appreciation to Dr. A. H. Hendrick- son, Pomologist in the Experiment Station ; Dr. W. H. Chandler, Pro- fessor of Horticulture ; and H. M. Butterfield, Specialist in Agricultural Extension, wlio kindly reviewed the manuscript and made helpful sug- gestions; to Dr. S. W. Shear, Associate Agricultural Economist, for suggestions concerning the economic considerations and assistance in arranging the tables; to Dr. Leslie M. Smith, Assistant Entomologist, for suggestions concerning the insect pests of the strawberry ; and to Earl V. Goldsmith, Associate in the Experiment Station, for aid in the preparation of the circular. The author is particularly indebted to Mr. E. H. Haack, Manager of the Central California Berry Growers' Asso- ciation, for supplying data concerning the production and movement of strawberries in the central-coast district ; and to the Railway Express Agency, Southern Pacific Company, Western Pacific Railroad Com- pany, and Central California Traction Company for data supplied on the movement of strawberries. Many growers and growers' organizations have contributed to the information contained in this circular and these are especially thanked.