CALIFORNIA AGRICULTURAL EXTENSION SERVICE CIRCULAR 66 October, 1932 Tomato Production in California O. H. PEARSON AND D. R. PORTER 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 CONTENTS PAGE Introduction 3 Tomato-producing districts 5 Shipping seasons 7 Locations for tomato growing 9 Cropping system 9 Varieties 12 Earliana 12 Globe 12 Marglobe 12 Stone 15 Norton 15 Greater Baltimore 15 Morse's Canner 15 Italian Stone or Quartinino 15 San Jose Canner 18 Santa Clara Canner .• 18 Trophy (Alameda Trophy) 18 Italian varieties 20 Growing the plants 20 The hot-bed-coldframe method .. 20 The coldframe method 22 The open-bed method 23 Care of plant beds 23 Seeding directly in the field 23 Field culture .' 24 Irrigation 27 Planting distances 29 Staking and pruning 29 Fertilizers and manures .' 30 Harvesting ! 31 Packing 32 Artificial ripening 32 Yields 34 Insects 34 Hornworms (Protoparce sexta and P. quinquemaculata) 35 Corn earworm (HeliotMs obsoleta) 36 Tomato pinworm (Gnorimo schema ly coper sicella) 37 Cutworms 38 Armyworms 39 Darkling ground beetles (Blapstinus sp.) 39 Flea beetles 40 Vegetable weevil (Listroderes otliquus) 40 Nematodes or eelworms (Caconema radicicola) 42 Diseases 42 Fusarium wilt (Fusarium lycopersici) 43 Verticillium wilt (Verticillium albo-atrum) .. 44 Late blight (Phytopthora sp.) 45 Bacterial canker (Aplanobacter michiganense) 47 Nailhead spot (Macrosporium sp.) 48 Damping-off (Pythium, Rhizoctonia, etc.) 49 Blossom-end rot... 50 Tomato virus diseases 50 Mosaic 51 Streak. v> Curly top 52 Seed growing _ 54 Acknowledgments 57 TOMATO PRODUCTION IN CALIFORNIA 0. H. PEARSONi and D. R. P0RTER2 INTRODUCTION Tomato growing is one of the important agricultural industries of California. In 1930, there were 5,384 carloads of table stock shipped, while the canneries packed 4,245,175 cases of No. 2% cans of whole tomatoes and 3,452,457 cases of tomato products such as pulp, puree, catsup, paste, and juice. Shipments of table stock in 1930 were 16.2 per cent of all the shipments of tomatoes in the United States, and California packed 20.3 per cent of all the tomatoes canned in the country (table 1) . Indiana is the only state having a greater acreage in tomatoes than California. TABLE 1 California Tomatoes : Production for Market and for Manufacture Use Year Total for California Per cent of U. S. crop produced by California Acres Tons Acres Tons Market 1929 1930 15,800 23,150 38,472 60,928 10.6 14.0 7.9 12.7 1929 1930 41,680 44,210 241,700 336,000 14.1 12.2 17.1 20.3 Total 1929 1930 57,480 67,360 280,170 396,930 12.9 12.75 14.8 18.6 The importance of the tomato crop in California becomes evident when one realizes that of the 450,000 acres of truck crops in the state, approximately 15 per cent are planted to tomatoes, one-third of this acreage being for shipping. Acreage and production fluctuate from year to year, but the tendency is toward a steady increase, especially in the shipments of tomatoes in the fresh condition. Large quantities are raised for local markets ; a considerable acreage is grown especially for seed production ; and in the home gardens the tomato is usually a crop of major importance. 1 Junior Olericulturist in the Experiment Station. 2 Assistant Olericulturist in the Experiment Station. 4 California Agricultural Extension Service [Cm. 66 The average yield in California varies from 5 to 7 tons per acre. Although this figure is above the average for the whole United States, even greater yields are attainable with the favorable soil and climatic Fig. 1. — A map of California showing the areas engaged in the production of tomatoes for manufacture and shipping. Each dot represents 100 acres. No attempt has been made to represent tomatoes grown for local market use, although in certain cases the acreage is large, as in Los Angeles County, where 600 acres are grown for this purpose. conditions existing in many sections of California. Yields of 10 to 25 tons per acre are frequently obtained by skillful growers. Surveys in other states have shown that the grower whose yield is below average is 1932] Tomato Production in California liable to lose money on the crop, while other growers in the same district whose yields are above the average, make a profit. The object of this circular is to describe methods of growing and handling tomatoes and to point out in a general way some of the principles underlying better production. In considering the culture of such a crop as tomatoes, however, one must always take into account the diversity in soil and climatic conditions existing within the state, the variety, and the purposes for which the crop is grown. TOMATO-PRODUCING DISTRICTS The distribution of commercial tomato production within the state is shown in figure 1. Each mark represents 100 acres. No attempt has been made to indicate the acreage for local use, even in the areas adja- Fig. 2. — Method of protecting tomatoes sown directly in the field, in Imperial Valley. The seed is planted in hills on the south side of beds running east and west. Thinning is deferred until danger of frost is over, in February. (From Cir. 263.) cent to large cities, where several hundred acres are grown to supply the local trade. As shown by the map, the production areas may be divided into three main sections: (a) interior valleys, (b) coastal val- leys, and (c) southern California. In general, the southern district pro- duces shipping tomatoes, whereas the majority of the acreage in the interior and coastal valleys is for canning purposes. The Imperial Valley and a small district near Mecca, Riverside County, together produce about 2,500 acres of tomatoes for early ship- ment to cities west of Chicago during April and May. The seed is planted directly in the field in October or November and is protected by small windbreaks during the winter (fig. 2). A small district near the county line between Fresno and Tulare counties produces the next earliest fruit, for shipment during May and 6 California Agricultural Extension Service [Cm. 66 June. Here the seed is planted in November in beds where the seedlings can be protected before transplanting into the field about February 15. Small areas near Madera and Merced produce early tomatoes, that portion of the crop which matures during June and early July being shipped, the remainder going to the canneries for the manufacture of tomato products. In these districts the vines are usually staked and pruned (fig. 3). Early or midseason varieties are used, the seed being planted in January and the plants set in the field during March. ^mmwm Fig. 3. — Harvesting tomatoes near Merced. The variety is New Stone ; it yields about four tons of salad tomatoes per acre, and about six tons of canning tomatoes after the market season is over. The margin of profit is small, for the cost of labor in growing the crop amounts to nearly $100.00 per acre, not including cost of harvest. Stanislaus, Sacramento, San Joaquin, Placer, Alameda, San Mateo, Santa Clara, Contra Costa, and Monterey counties all produce chiefly canning tomatoes. The seed is planted in late January, and the plants are set in the field in late April. A considerable acreage near the coast, however, is grown for shipping, the harvest period being from Sep- tember 15 until frost, usually in November. Small quantities are also shipped in early fall from the valley counties. In the south the production of canning tomatoes is, in general, limited to sections near Los Angeles. The seed is planted during late February or early March, and plants are set in the field in May or June. The portion of the crop maturing after October 1 is often shipped. The southwestern part of San Bernardino County and the northwestern part of Riverside County also produce tomatoes for canning. 1932] Tomato Production in California 7 San Luis Obispo, Ventura, Santa Barbara, and Orange counties produce shipping tomatoes from late September until frost in late November. The seed is planted in April, and transplanting begins in June. San Diego County produces large quantities of tomatoes for ship- ping. The region is nearly frost free, so that fruit is produced from October until January. The seed is planted during late May, and the plants are set in the field about the middle of July. Commercial tomato production has recently become important in Tulare County; during 1930, furthermore, growers near Oroville planted about 400 acres. In Sonoma County, tomato production has recently decreased, and other crops have been substituted. Although tomatoes are grown in every county, in districts not mentioned above they are raised chiefly for local trade or in home gardens. SHIPPING SEASONS To make clearer the opportunities for tomato production for ship- ment to outside markets and to show the relation of tomato shipments from California to those from other sections and from the United States as a whole, the carlot shipments in 1930 from the leading tomato dis- tricts are shown in table 2. Although minor changes in volume and season occur from year to year, the general shipping cycle remains about the same. Tomatoes are shipped throughout the year; but from December to May, as table 2 shows, the markets are supplied almost entirely by the east coast of Florida and imports from Mexico. Shipments from other sections gradually increase during the spring until a peak is reached in June. Texas, Mississippi, and the west coast of Florida furnish most of these. The Imperial Valley supplies a few carloads for middle western cities. Thereafter, shipments decrease ; and the total number of cars moved during August is relatively low. This is the period of local production in the North and East, so that carload shipments from outside districts are not needed. Late in August the market improves, because of the exhaustion of home-grown supplies. This leads to a second peak of shipments from Utah, New Jersey, Ohio, Indiana, and New York during the fall, which declines rapidly as frost cuts down one shipping section after another. Shipments of California tomatoes during September, October, and November comprise most of the toma- toes moved at that time. As shown in table 2, in October and November nearly three-fourths of the tomatoes moved by the railroads are from California. Ohio, Indiana, and Florida supply the remainder. Although California Agricultural Extension Service [Cm. 66 Eh W "3 o H 3 OS C* * ►-9 t}< co os N lO 0O OS 00 o to r^ oo 0000i-IOC005l^-O 00 COOO-HCOCMOOCO CO i-l CM i-l OO CO CM CO OS CM 01 *-> > 00 H M «« OS O 10 CO OS CM in os CM HO OO t- S 1 »o 10 00 CO f-l a < CO eo ■* H CM *H. CO CO CO CM 3 r- > US 1 c i c C > c ) c B e *- R c j a i p c , f .. -t- e c 1 1 I .1 1 is "a a i O ft ft, 1. s a g c t- k c I 5 a a f c i 0) 'S p 0) XJ h H a c c g 1 1932] Tomato Production in California 9 shipments of early tomatoes in California are not very important, because of heavy production in other sections nearer to the larger cities, for a period of two months in the fall — October and November — California tomatoes have command of the entire country. Production for shipment in this period seems especially promising. LOCATIONS FOR TOMATO GROWING Before engaging in extensive tomato production, the grower must be assured of a profitable outlet for his crop ; that is, he must have access to a good local market, must be near a cannery or other manufacturing plant, or must be so situated that he can ship to advantage. He should generally not attempt to grow the crop for shipment unless the acreage is large enough to make carload lots possible, either for the individual grower or for groups or associations of small growers located in the same community. The season at which the crop will mature and the probable market conditions existing at that time should be carefully considered. The tomato is a heat-loving plant, and the long growing season in most parts of the state favors tomato production. Localities subject to late spring or early fall frost, or those with a very cool summer climate, are usually not suitable for the crop. Although the tomato succeeds on many soil types, soil may influence yield, quality, and time of maturity. Sandy soils favor early maturity, while heavier soils are especially suited to late maturing or fall crops. Muck or peat soils, though not usually considered suitable for tomatoes, have produced excellent crops of good quality when the moisture supply was not excessive. Good drainage is always essential. Soils that are too moist for any considerable period during the growing season usually produce a poor crop, because of excessive vine growth and poor set of fruit. Soils excessively rich in nitrogenous matter may produce similar effects. The tomato will root deeply unless prevented by plow sole, hardpan, or poor drainage. The history of the land from the standpoint of alkali content is also important, for the tomato is very susceptible to such injury. CROPPING SYSTEM A large proportion of the tomato crop in northern and central California is produced in rotation with a winter crop of spinach. The tomato plants are pulled and burned after picking is finished in Novem- ber ; the land is fitted and sown to spinach at once. The spinach crop is harvested in March and April, and the land is prepared for tomatoes 10 California Agricultural Extension Service [Cir. 66 again, the plants being transplanted into the field during May. This combination, although a good one, may lead to loss if the same land is continuously cropped. Tomatoes should be grown not more than once in four years on the same piece of land ; they should be grown in rotation with other crops. Certain diseases and insects often become prevalent when tomatoes are grown continuously. The double-cropping of land with winter vegetables and tomatoes is practicable only when the tomato crop can be irrigated. Fig. 4. — Tomatoes as an intercrop in a three-year-old peach orchard at Merced. Though the trees are 24 feet apart, there is room for only two rows of tomatoes. Competition for water between trees and tomatoes will be severe, requiring heavy irrigation. (From Cir. 263.) An unfounded idea held by some growers is that tomatoes exert an injurious effect upon subsequent crops. When the dead tomato vines are plowed under, they have a beneficial effect from the standpoint of the added organic matter. When they are piled and burned, however, the accumulation of ash in these spots may be injurious to the next crop. Tomatoes are extensively grown as an intercrop in young orchards (fig. 4), a purpose to which they are well adapted when their irrigation does not conflict with the requirements of the trees, as it does, for example, in young walnut groves. Deciduous fruit orchards should not be intercropped with tomatoes after the third year, because the com- petition for water and plant food will interfere with the growth of both trees and tomatoes. 1932] Tomato Production in California 11 Fig. 5. — Characteristic fruit of the Earliana, variety. The fruit typically is a slightly lobed and flattened sphere, smooth at both stem and blossom end. The blossom end often has a medium-sized scar; light-colored lines radiating from this scar are a striking characteristic of the variety. The walls of the fruit are thin, and the core is not pronounced. (Natural size.) 12 California Agricultural Extension Service [Cir. 66 VARIETIES The grower should get high quality seed of a variety adapted to local conditions and uses. The cost of good seed is only a small item, for one pound will produce enough plants for 25 acres of canning or late shipping tomatoes. The choice of a suitable variety of tomato depends upon the use for which the crop is intended, the climate of the locality, the season for marketing, and the liability to disease infection or insect infestation. Many varieties have been developed whose fruit is early maturing, but is unsuited for shipping and is generally too small to be suitable for canning. The fruit of certain other varieties are too large or too rough for fresh-fruit markets, but possess qualities which make them suitable for manufacturing purposes. The following varieties have been found satisfactory for one or more purposes in California. Earliana. — Several improved strains of the Earliana variety (fig. 5) are now available, namely North Dakota Earliana, Morse's Special Early, Alacrity, Burbank, King of the Earlies, First Early, and Morse 's 498. The original Earliana was a flat, rather rough tomato ; but the improved strains just mentioned usually produce smooth, globular fruit. The plants of Earliana are comparatively small and weak growing, requiring only one-third as much space to the plant as late varieties. The fruit is red, early in maturing, but small compared with late varieties. Earliana is an excellent variety for the extra-early crop of growers catering to a local market. It is also used to some extent for spring shipments, First Early and 498 being the chief strains used in the Imperial Valley district. Globe. — The fruit of Globe is pink, round to very slightly flattened in shape (fig. 6), somewhat larger and about two weeks later than Earliana. Globe has been the standard shipping variety of Florida and the Gulf States for many years and is being used to a considerable extent in the cooler coastal regions of California. Its use is not recommended in the interior valleys. Marglobe. — The variety Marglobe was introduced a few years ago by the late F. S. Pritchard of the United States Department of Agricul- ture. It is the result of hybridizing the Marvel and Globe varieties, followed by selection for the fusarium-wilt resisting quality of Marvel and the shipping quality of Globe. These characters have been com- bined in Marglobe to a satisfactory degree. In addition, this variety possesses considerable resistance to nailhead spot (Alternaria) , a serious disease in some sections outside California. Largely for this reason, 1932] Tomato Production in California 13 Fig. 6. — Typical fruit of the Globe variety. In shape, the fruit is a slightly flattened sphere, with a smooth outline. The blossom end should have no appreciable scar. The walls are heavy, and the core is very slight. The length and posture of the sepals are especially characteristic. The skin of this variety is thin and cracks badly. (Natural size.) 14 California Agricultural Extension Service t ClR - 66 Fig. 7. — Typical fruit of the Marglobe variety. The side and cross walls are especially heavy. The fruit is either a slightly flattened sphere or blocky like a cube with rounded edges. It has a tendency toward wide, corky, longitudinal cracks at the stem end, although the skin is tough. (Natural size.) 1932 ] Tomato Production in California 15 Marglobe is being used extensively in the southern states and in Mexico. The fruit (fig. 7) is round, red, of medium size, of good shipping quality, and medium early. The variety has proved satisfactory in Imperial Valley and in southern California for fall shipping, although in the San Joaquin and Sacramento valleys the fruit often fails to reach a satis- factory size. Stone. — The Stone variety is usually classed as late, the fruit ripen- ing nearly a month after Earliana but two weeks earlier than San Jose Canner and related canning varieties. In size the plants are inter- mediate between Earliana and San Jose Canner. The fruit is red, slightly flattened, generally smooth, free from "cat faces," and of medium to large size (fig. 8). Stone has been used in the Los Angeles district as a dual-purpose variety for late shipping and canning. It is also used to some extent for fall shipment in central and northern Cali- fornia, Although its smoothness commends it to the canner for putting upa" solid pack, ' ' the fruit tends to be too small for economical canning, except where the soil is very fertile and moist, or where the growing season is too short or too cool for the larger canning varieties. Norton. — The strain of Stone highly resistant to the fusarium-wilt disease is called Norton. It was introduced in 1918 by the late F. S. Pritchard of the United States Department of Agriculture. Its wilt- resistance has been well demonstrated in Los Angeles and San Diego counties, and as the plant is practically identical with Stone in all other respects it should be grown wherever a variety of the Stone type is desired. Greater Baltimore. — Greater Baltimore is very similar in appear- ance to Norton and Stone in size of vine and of fruit, but is a week or ten days earlier. It is not wilt resistant. Morse's Canner. — Although originally selected for canning pur- poses, the variety known as Morse's Canner is now more important for the late market crop. The plants in general resemble Stone; the fruit, however, is considerably larger, and is generally smooth, and globular or slightly flattened. This variety probably produces the largest toma- toes of any smooth-fruited types. Its large cells and its failure to color evenly are said to be its main defects from the canner 's viewpoint. Italian Stone or Quartinino. — In the Merced district the medium- early variety grown is known as Italian Stone or Quartinino, but is en- tirely different from Stone. When not pruned to a single stem the plants assume a very distinct, compact, semi-erect type of growth. The dense foliage protects the fruit from exposure to sunburn. The fruit is 16 California Agricultural Extension Service t ClR - ^m$*£ Fig. 8. — Typical fruit of the Stone variety. The Stone is a slightly roughened tomato at the stem end, often with a pronounced scar at the blossom end. It is flat, usually somewhat oval in cross section. The interior is very often ' ' seedy, ' ' and the walls are not especially heavy. The core tends to be rather prominent. The fruit of Norton and Greater Baltimore is very similar to Stone in appearance. (Natural size.) 1932] Tomato Production in California 17 Fig. 9. — This shows the irregular or rough blossom ends, with the large stylar scar, commonly found in the old types of San Jose Canner variety. (From Hilgardia, Vol. 2, No. 2.) Fig. 10. — View of the fruit of an improved strain of San Jose Oanner variety, which has been selected over a period of years for smoothness and large size. These improved types are very similar to the Santa Clara variety. (From Hilgardia, Vol. 2, No. 2.) 18 California Agricultural Extension Service [Cir. 66 red, flattened, medium in size, inclined to be round or corrugated, and more acid in flavor than that of other varieties. The improved strains of Earliana have been found to be considerably superior to it in earliness and in production of U. S. No. 1 grade fruit. San Jose Canner. — The name San Jose Canner is generally applied to a large, rather rough-fruited, late maturing variety, widely used for the canning crop in central and northern California. California Trophy, Santa Rosa, Diener, San Felipe, and Jap Canner are other names applied to this variety or to certain growers' strains of it. It has very large fruit, much flattened in shape ; and many specimens have a deep corrugated depression at the stem end and a large, irregular scar at the stylar or "blossom" end (fig. 9). These defects cause a high percentage of waste in preparing the fruit for canning. The San Jose Canner possesses, however, a. high degree of solidity and an excellent color, which commends it strongly for canning. Furthermore, the large size of fruit and the heavy yield make this variety an economical one to grow and to harvest. The improved strains (fig. 10), though in general much smoother and more uniform in shape than the original type, retain the large size, solidity, and color of the parent. The solidity results from a tough epidermis, a large "meaty" core, and numerous small cells or seed cavities with thick radial walls. Santa Clara Canner.— Santa Clara Canner is an improved strain of the canner type developed by the Ferry-Morse Seed Company from San Jose Canner (fig. 11) . It has to a large extent replaced San Jose Canner as a cannery tomato. It is offered in early, medium or regular, and late strains. CaL 1, Cal. 55, Caleven, and Calpac (fig. 10) are strains devel- oped from similar San Jose Canner stock by the California Agricultural Experiment Station by means of several years' selection for a smoother, more uniform type than the original variety. Most of these are, however, late maturing strains, adapted only to early soils. Trophy (Alameda Trophy). — The variety grown under the name Alameda Trophy in California differs from the original Trophy variety. It is used extensively for making catsup and other manufactured prod- ucts, especially in Alameda County; but the fruit is too rough to be economically canned. It is desirable for manufacture because the pro- longed processing does not affect the color of the product. The fruit is medium to large, flattened, usually very rough or corrugated, and similar to that of San Jose Canner in internal structure. The deep pink color of the pulp is partly a varietal characteristic and partly a result of the nonirrigated condition under which the plants are grown in Alameda County. Trophy is earlier than most strains of San Jose 1932] Tomato Production in California 19 m ®&*m 4f IV ' 1 •/% Jj^^ ^ * t', g #» *4y* Fig. 11. — Fruits of the Santa Clara Canner variety. Above, is a side view of a tomato, natural size, showing the lobed stem end. Below, are vertical and cross sections of twenty fruits showing the range in size and internal structure. The fruit of this variety is variable in size and structure but is typically heavy walled, with many small seed cells and a characteristic fibrous core. Nearly all fruits have small, sterile seed cells in the interior of the central fleshy mass. This is the tomato most extensively used for canning and manufacture in central and northern California. 20 California Agricultural Extension Service [Cir. 66 Canner and in cool regions is more productive. In many districts, how- ever, the early strain of Santa Clara Canner is replacing" it. Italian Varieties. — In recent years much interest in certain Italian varieties has been aroused in the United States, by the extensive impor- tation of canned tomatoes and tomato products from Italy. Of the Italian varieties, Prince Borghese and King Humbert are the most suitable for a solid pack of small whole fruit. The fruit of these varieties is about twice as large as that of the common Red Pear but smaller than that of Earliana, and is borne in large clusters, It is of superior color and solidity, elongated in shape, with only two cells. The King Humbert variety has a higher content of solids than American varieties — a valu- able feature from the manufacturer's viewpoint. The fruit of Prince Borghese, however, has a rather low solid content. An outstanding characteristic of these tomatoes is their ability to remain sound and firm on the plant for weeks after attaining full color. Their moisture content does not change appreciably during this period. The main objection to these varieties is the high cost of picking occasioned by the small size of the fruit — a fault partly balanced by the fact that only a few pickings are necessary, as the tomatoes can be left on the plant until a large number of them are ripe. Other Italian varieties tested at Davis were inferior to the ordinary California types in size, uniformity, and yield. GROWING THE PLANTS For the sake of economy of seed, earliness, and convenience in raising the crop, the plants are usually grown in beds of one kind or another and thence transplanted to the field at the proper time in the spring, usually after danger of frost is past. The best method of growing them depends on the locality and the season at which the crop is desired. The Hotbed-Coldframe Method. — The hotbed-coldframe method is generally best for early market crops, and is also used even for the late shipping and canning crop in central and northern California. This method is here described in detail because its more extensive use seems desirable. The hotbed frame should be located in a warm, sunny, well-drained spot. The best covering for the hotbed is glazed sash, but unbleached muslin (grade DD) is also satisfactory, especially if treated with a waterproofing compound. About one foot of fresh horse manure is placed in the bed and tramped down, and a layer of soil four inches deep is placed over this. A sandy soil or a mixture of one-half sand and 1932] Tomato Production in California 21 one-half garden soil is best for the hotbed because it gives stronger plants with better root systems than does a very fertile or heavy soil. The seed is usually planted early in January, three months or more before the time of field setting. It is sown broadcast or drilled into rows about 4 inches apart and covered about % inch deep. If good seed is sown at the rate of 12 or 15 per inch of row, one hotbed 6 by 24 feet in size should produce about 50,000 seedlings. The hotbed should be kept warm and moist until the plants are up ; thereafter, it should be well ventilated during warm days and watered sparingly. Fig. 12. — The type of coldframes used for plant growing in central and northern California. They are 8 to 12 feet wide; the sides and ends consist of 1 by 12-inch boards; and the frames are covered with sheets of unbleached muslin. The seedling plants from the hotbeds should be transplanted into these coldframes about 2 by 4 inches apart. Electric soil heating units are now available which will furnish more uniform heat than does manure, and can be completely controlled. The chief drawback is the expense of installation and operation but with further experiments by the manufacturers, such installations may eventually prove economical. As soon as the seedlings show their first rough leaves, they are ready for transplantation to another bed, usually a coldframe (fig. 12). This task is worth doing well and carefully. The coldframes, although usually wider than the hotbeds, are prepared in much the same way except that no manure is placed under them. In the coldframe should be placed about 4 inches of fine soil, preferably a mixture of one part garden soil, one part sand, and one part rotted manure, all well mixed and passed through a screen of %-inch mesh. A suitable covering for the frames may be made of unbleached muslin, sewed together in sheets or tacked 22 California Agricultural Extension Service [Cm. 66 to frames of convenient size for handling ; burlap sacking is sometimes used. The seedling* plants from the hotbed are usually set in the bed about 2 by 4 inches apart. Water should follow transplanting, and the frames should be kept covered a few days until the plants have taken root especially if the sunlight is strong or the weather windy. Once reestab- lished, the plants should be given only enough water to keep them growing at a moderate rate. The frames should be ventilated freely during the daytime. When the plants are about 8 inches high, the terminal bud should be pinched out of each, to prevent the plants grow- ing any taller and to encourage the development of thick, stout stems and good root systems. At the same time, shoots begin to develop in the axils of the leaves. In this manner, the framework for a large, bushy plant is started before the plants are set in the field. This method of "topping" the plants two or three weeks before transplanting to the field has been found, in experiments, to result in considerable increases in yield of early fruit. A variation in the hotbed method as described above is to transplant the seedlings into small clay pots or into "dirt bands" from which the plants can be removed without disturbing the roots, This method, although more expensive, may be profitable to the market gardener who caters to a demand for extra early fruit on a local market. Another method often used by gardeners and seedsmen is to transplant the seedlings to boxes (flats) about 18 by 24 inches in size and 3 inches deep. For a week or ten days before transplanting the plants to the field one should leave the beds open day and night unless frost threatens, and apply only enough water to keep the plants from prolonged wilting. This treatment toughens or ' ' hardens ' ' the plants so that they will stand transplanting without severe wilting, which so often kills tender plants when set in the open field. Well hardened plants are slightly more resistant to frost than are succulent ones, and they also take root more rapidly. The Coldframe Method. — Tomato plants may be started in cold- frames in localities where they must be sown during cool weather but not so early as to require the hotbed method. Frames are prepared running east and west in a sheltered sunny spot, and a four-inch layer of sandy, moderately fertile soil is then placed in them. The seed is sown by hand or with a seed drill, being planted thinly in rows 4 to 6 inches apart. After germination, the beds should be weeded, and the plants thinned to about three per inch. This method can be used to produce large numbers of plants cheaply ; but good, large, stocky plants 1932] Tomato Production in California 23 with well-developed roots are seldom produced, because the seed is usually planted too thick and the necessary thinning is not done. The plants are pulled and transplanted directly to the field from the coldframe. The Open-Bed Method. — This is probably the cheapest way to grow plants but is not adapted to sections having short growing seasons, nor to early crop production. It is used for growing plants for the late shipping crop in southern California and may also be suitable for late market crops elsewhere, when relatively quick-maturing varieties like Marglobe and Norton are used. For the open-bed method, beds are prepared in a well-drained, sheltered spot preferably where the soil is sandy. Narrow beds, 30 to 36 inches from center to center, are thrown up with a lister; the ridges are harrowed down and leveled with a planker. Two rows are sown on each bed, and the furrows between the beds are used for irrigation. The seed is drilled in with a seeder as soon as the soil becomes warm and danger of frost is over. The seed should not be planted too thick in these open beds, and thinning should be practiced where the plants stand too close together. Care of Plant Beds. — Regardless of the plant bed type, the soil must be weeded and cultivated to prevent crust formation around the plants. Thinning is often necessary, for if crowded the plants will develop weak, spindling stems and will be of very poor quality. Particular care should be given to the watering of plant beds, for overwatering results in weak, sappy, ' ' leggy ' ' plants that recover slowly after transplantation to the field. Excessive moisture, especially if given late in the day, encourages damping-off, a disease that sometimes destroys many plants overnight. Waterings should usually be given several days apart, and not until the plants have begun to wilt, since no harm is done if the plants are checked temporarily by lack of water. Holding plants for a long period of time after they have reached transplanting size is, however, undesirable. For this reason one should not plant earlier than is neces- sary to get plants of the correct size for transplanting at the desired time. Ten to twelve weeks should be allowed for plant growing. The day before transplanting to the field, the beds should be watered heavily so that the plants can be removed easily. The soil must be loos- ened with a spade or similar tool to minimize injury caused when the plants are pulled from the bed. Seeding Directly in the Field. — In sections having a long growing season, tomatoes may be planted directly in the field. This method is wasteful of seed, involves considerable labor in thinning, and cannot be practiced when tomatoes follow a winter crop of spinach or other 24 California Agricultural Extension Service [Cir. 66 vegetables. On the other hand, direct field planting lessens expense and the interruption of plant growth which occurs under the transplanting process (fig. 13). It is a cheap method for the production of an excess number of plants, sometimes necessary where there is danger of loss from curly top. Nontransplanted tomatoes also develop a deep taproot (fig. 14), which gives them an advantage under dry-farming conditions. Only varieties that mature in a medium or short season should be grown Fig. 13. — This shows the more rapid growth of plants from seeds sown directly in the field on May 1 (at the left), compared with plants of the same age trans- planted from a seed bed (at the right). The difference in size of plants gradually disappears later in the season. Photographed June 18, at Riverside. (From Cir. 263.) in this way, unless the season is very long. The seed is planted in hills before danger of frost is over. Later, the plants are thinned to two in a hill. In two years test at Davis, about the same yields of ripe fruit were obtained from field-planted and from hotbed-grown plants. In the Imperial Valley almost the entire acreage is ordinarily grown from November plantings made directly in the field and pro- tected with brush and paper shelters until danger of frost is past (fig. 2). FIELD CULTURE Tomato land should be deeply plowed in the fall whenever possible ; after spinach or other winter crops, the ground should be deeply plowed as soon as possible after the winter crop is removed. In the spring, 1932 ] Tomato Production in California 25 before the soil surface becomes hard and dry, the land should be disked and floated to kill the weeds and to pulverize the surface soil. The method of preparing for the plants and the method of transplanting depends upon the locality and the soil conditions. In some sections, when planting for the early crop, one may set the plants without water- ing if the soil is handled properly. Under such conditions, the field is leveled and marked off in both directions. The plants, if set by hand Fig. 14. — The root systems of tomato plants. The one at the left was trans- planted from the hotbed. It has no taproot but does have a number of shallow laterals. At the right is shown a plant from direct field planting. It has a long taproot, and the laterals are deep. (Prom Cir. 263.) (fig. 15), are then placed at the intersections. In setting large acreages, however, one can save much time and labor by the use of a mechanical transplanter. These machines, of which there are several types on the market, set the plants as well as they are usually set by hand, and if necessary can be used to water the plants. In dry sections, and in most sections during dry seasons, the plants must be watered as they are transplanted. This is almost always the case in setting the late crop. If irrigation is practicable, the simplest plan is to plow out a furrow for each row. The plants are set the proper distance apart on the edge of the furrow, and a small stream of water is turned into each row as it is set. Cultivation must follow within a day or two to prevent a hard crust from forming around the roots. At this time one should work the soil toward the plants, thus beginning the bed, which should be gradually formed for each row. 26 California Agricultural Extension Service [Cir. 66 Sometimes a number of barrels of water are placed in the field at convenient intervals. As the plants are set, a little water is poured about the roots of each. In transplanting tomatoes, one should cover the roots as deeply as possible, usually setting the plants 3 or 4 inches deeper than they were in the plant bed. New roots develop along the stem, giving the plant a ;--*.■ Fig. 15. — Upper: Planting tomatoes by hand near Centerville, California. A large portion of the tomatoes grown are planted in this way, almost as cheaply as by machine. One man can plant about l 1 /! acres per day, but there is no overhead for machine depreciation in this method. Lower: planting tomatoes by machine near Hollister, California. Two machines are drawn by one tractor. A crew of eight men is required: one man drives the tractor, two men on each machine place and water the plants, one man follows each machine on foot to be sure that every plant is properly aligned, and one man drives the water truck to supply the tanks on the machines. About 20 acres can be planted in a day or 2% acres per man — twice as much as by hand. 1932 ] Tomato Production in California 27 more extensive root system than can be obtained when it is set shallow. Deep setting is of course more laborious than the customary shallow setting, bnt it enables the plants to make use of the moisture in the lower soil. Deep plowing or subsoiling also aids in securing deep penetration of the roots. Plants with deep roots are most fully assured of an even moisture supply, do not require frequent irrigations, and do not suffer from the sharp fluctuations of having alternately too much and too little water. Fig. 16. — Tomatoes furrowed for the first irrigation after transplanting. Fruit setting on these plants has already begun. (From Cir. 263.) Irrigation. — In some parts of the state, satisfactory tomato crops can be grown with little or no irrigation, provided the plants have been given an opportunity to develop deep root systems. In districts having over 15 inches of winter rainfall and a cool summer, as does the San Francisco bay region, satisfactory yields can be secured without appli- cation of water. In most sections, however, some irrigation results in larger yields. The number and frequency of irrigations are determined by local conditions, chiefly by the type of soil, the temperatures during the growing season, and the size of the plants. Enough water should be used to keep the plants growing steadily. The furrow for the first irrigation should be as close to the plants as possible (figs. 16 and 17) so that that moisture can seep down to the roots. The furrow for successive irrigations should each time be farther 28 California Agricultural Extension Service [Cir. 66 away from the plants so that by mid-season a broad, low bed will have been formed (fig. 18) . By keeping dry the surface of this bed, on which the vines and fruit rest, one can decrease the loss caused by fruit rots. Recent experimental results indicate that the only benefit derived from Fig. 17. — Irrigation of tomatoes from slip- joint pipe. By the use of a V-crowder, a basin 2 feet wide has been made between the rows. This is advisable where the land slopes very steeply. As the lateral movement of moisture is negligible, however, a furrow closer to the plants would be more effective. After a run of six hours, the moisture had not penetrated more than 6 inches to each side of this basin. (From Cir. 263.) ,W Fig. 18. — Tomatoes furrowed for late irrigation. By this time rooting is sufficiently deep and spreading so that the irrigating furrows need not be close to the plants. (From Cir. 263.) cultivation is in weed control ; weed cutting or scraping of the surface is therefore all that is needed once the plants have become established. Tomato plants, being deeply rooted, draw water from a large volume of soil. If the soil is well filled with water, as after a winter of normal rainfall, the plants may go uninjured without additional water for several months. In many plants, as has recently been shown, growth is entirely normal until the supply of moisture becomes so low as to cause wilting. No data are available for tomatoes, but the water require- 1932] Tomato Production in California 29 ments for this crop are probably much the same. According to these results, a heavy irrigation whenever the supply of soil moisture becomes dangerously low will replenish the water supply without injury to the plants. The established custom, however, is to irrigate for the first time after the fruit starts to set, and at regular intervals, according to soil type, for the remainder of the season. Heavy soils are usually irrigated three times with 4 or 5 acre-inches per acre during the season ; lighter soils, where the rate of evaporation is high, as in the interior valleys or the Imperial Valley, are irrigated every two weeks or oftener. The spring shipping crop in the Imperial Valley is irrigated after each picking. In some sections where the crop is grown for late fall shipment, the practice is to irrigate just as the first flowers open. This procedure is said to prevent the setting of early fruit and may encourage the development of a larger plant that will produce more fruit. Planting Distances. — The planting distance is determined by the variety, the soil, and the season at which ripe fruit is desired. Early tomatoes, grown under intensive culture where the plants are staked and trained to a single stem, as in the Merced district, are set 15 inches by 3 feet apart, so that 12,000 plants are required per acre. The late shipping and canning crop of such varieties as Stone, which generally make vigorous vine growth, are set 6 by 6 feet ; and the San Jose Canner requires 6 by 8 or 8 by 8 feet. The late varieties, then, require from 700 to 1,200 plants per acre. Further modification may be necessitated by moisture and fertility conditions. In dry-farming, a wider spacing is more desirable than when the crop is grown under irrigation. Although wider spacings are more economical of plants and labor than are the closer plantings, there are no reliable data available to indicate just when wide or close plantings will pay best, Certainly the rows must be wide enough to allow cultivation and irrigation and to permit easy passage for the pickers without injury to the plants. Experi- ments in which two plants are set in a hill show slightly less total yield from the two than from a single plant. STAKING AND PRUNING The tomato plant naturally forms an erect stem, with wide side branches developing from the axil of each leaf. Under the special form of culture known as staking and pruning, the side shoots are pinched out as they appear. The growth is thus limited to the main or central stem, which is kept erect by being tied at intervals to a stake or bamboo placed alongside each plant, as shown in figure 3. On such plants the 30 California Agricultural Extension Service t ClR - 66 crop is limited to the fruit borne in the clusters which form at every third or sixth node on the central stem. If a strain of Earliana is grown one may better protect the fruit from sunburn and somewhat increase the yield by leaving two main stems per plant instead of one. Naturally this method of culture greatly reduces the number of fruits that a plant can bear, but this drawback is partly offset by the closer spacing of plants thus made possible. Plants to be staked and pruned may be set 15 to 18 inches apart in rows 3 feet wide. This arrangement gives three or more times as many plants per acre as an early variety grown without staking and pruning. It is claimed that staking and pruning result in increased earliness, greater production of early fruit, and larger fruit, than if the plants are allowed to grow naturally. On the other hand, this procedure involves higher costs of production per acre for labor, plants, and materials. At Merced, the New Stone variety yields about 4 tons of salad tomatoes per acre and 6 tons of canning tomatoes after the shipping season is over. Labor for taking care of the plants, pruning, tying, and staking amount to about 85 man-hours per acre. Cultivation costs about $60 per acre. Under California conditions, furthermore, staking and pruning give a lower total yield for the season, and the increase in early production may be more apparent than real, when considered on the basis of yield per plant rather than yield per acre. Although much of the early crop for shipping raised near Merced and other cities in northern California is grown in this way, the staking and pruning methods of culture should be limited to home gardens and to early-market crops when the area available is very limited. FERTILIZERS AND MANURES The tomato crop in California is generally not manured or treated with commercial fertilizers, and there is very little experimental work from which to recommend fertilizer practices with this crop. Evidently, however, upon most soils and in most localities of the state, tomato plants make satisfactory vegetative growth and produce large crops of fruit without artificial fertilization, provided that moisture and other factors are properly cared for. An exception to this rule may be found on some of the light, sandy, or gravelly soils in the southern part of the state, where tomatoes apparently respond with increased growth and larger yields when nitrogenous fertilizers are applied. In cases where plant growth is unsatisfactory, the cause should first be sought by determining whether injury is being caused by hardpan, alkali, disease, poor drainage, or faulty irrigation. The history of the soil — whether 1932] Tomato Production in California 31 or not other annual crop plants grown on it respond to fertilizer appli- cations — may also serve to indicate the requirements for tomatoes. Two common misconceptions about the fertilization of tomatoes — namely, that the injurious effects of too much nitrogen can be overcome by adding more of some other element, and that potassium fertilizers have some particular effects upon solidity and shipping quality — have been disproved. The safest way is to consult the County Farm Advisor and to try out some of the various fertilizer combinations in an experimental way. When a commercial fertilizer is to be applied, the best method, usually is to drill it into the row where the plants are to be set and to mix it with the soil before setting the plants. A fertilizer is generally most effective if placed where the roots will obtain it in the early part of the growing season. When the soil is deficient in nitrogen, it can probably best be supplied, under California conditions, in the form of ammonium sulfate. Three hundred pounds of this material per acre is usually a maximum application. HARVESTING The exact stage of maturity at which the fruit is picked depends upon the purpose for which it is to be used. For sale on local markets, for canning, and for pulp manufacture, the fruit should be fully colored, but firm, when picked. Nothing is gained by leaving it on the plant after it is fully colored. For shipment to nearby points the fruit is harvested in the "pink" stage, when about half of the surface shows distinct color. For shipment to distant markets, the fruit is usually picked m the "green-mature" stage — when fully grown but not yet showing pink or red color. Such fruit should, however, appear yellowish at the blossom end. A mature green fruit, if cut open, is found to have the cells well filled with the gelatinous pulp in which the seed is imbedded. In preparation for shipment, tomatoes in all these stages of ripeness are picked once a week. The ripe fruit, however, is placed in separate containers by the picker and is disposed of on the local market or to the canner. The pink fruit, that just turning, and the green fruit are hauled together to the packing shed to be sorted, graded, wrapped, and packed for shipment. In handling tomatoes, one should always take great care to avoid bruising or breaking the skin. The pickers should remove the stem from the fruit as it is picked, in order to prevent puncturing the skins of other fruit. 32 California Agricultural Extension Service [Cm. 66 Packing. — The two types of containers most used in California are the 4-basket flats, shown in figure 19, and the Los Angeles or Mexican lug, figure 20. The latter is used mainly for eastern shipment. Canning tomatoes are handled in 50-pound lug boxes, supplied to the growers by the canners at a nominal rental. Persons interested in the packing and shipping of tomatoes should secure Farmers' Bulletin No. 1291 from the United States Department of Agriculture, Washington, D. C. Fig. 19. — Tomatoes wrapped and packed in "tin tops." Baskets hold about five pounds each and are shipped in four-basket flats. This package is suitable for early market tomatoes, shipped in the pink or ripe stage to nearby markets. This is the usual package for shipment from the Imperial Valley. (From Cir. 263.) Artificial Ripeming. — Fruit picked in the green-mature stage ripens and colors up within one to three weeks, according to the tempera- ture and the degree of maturity when picked. The quality of such fruit is good when ripened in air, but when wrapped in tissue paper, as is the usual commercial practice, the flavor and texture of the artificially ripened fruit may be unsatisfactory. Upon arrival at market, the fruit is unwrapped, that showing sufficient color is sold at once, and that which is still green or only partly colored is placed in special ripening rooms. In the picking of green-mature tomatoes, careless pickers gather many that are not mature. The latter are worse than a total loss to the grower, for they never attain good edible quality when artificially ripened. Tomatoes picked in the "turning" stage, when they show a little pink color at the blossom end, are more uniformly of high quality when artificially ripened than those picked green. The most favorable temperature for rapid ripening of tomatoes is between 70° and 80° F. Below 60°, the ripening process is very slow. 1932] Tomato Production in California The maximum storage life of tomatoes is obtained with a temperature between 50° and 55° F. They can be held for riot more than three weeks at this temperature, and on removal to a temperature of 70° to 80° will attain ripeness in another week. If they are stored for a longer period, the loss from decay and breakdown becomes considerable. If stored at Fig. 20. — A tomato packing room, showing convenient arrangement of grading bins, movable packing tables, box chutes, and conveyors for the packed boxes. At the right are packed 30-pound Los Angeles lug boxes. This package is used for shipment of green fruit to distant markets, where the fruit is unwrapped, sorted, ripened, and repacked in smaller containers for retailing. (From Cir. 263.) 34 California Agricultural Extension Service [ Cir - 66 temperatures below 50° for more than a few days, the fruit does not color, but decays upon removal to a higher temperature. Prolonged cold storage of either green or ripe tomatoes is therefore impracticable. Persons interested in the storage and ripening of tomatoes should secure Technical Bulletin No. 268 of the U. S. Department of Agriculture. The ripening of tomatoes in storage can be greatly accelerated by adding small amounts of ethylene gas to the air of the storage room. A concentration of one part ethylene to 4,200 parts of air has been found effective. It will reduce by about one-half, the time required to change tomatoes from the green to full red color. The gas is obtained in com- pressed form in steel cylinders, from which the proper amount is dis- charged into the ripening room each day. The room has to be approxi- mately airtight to prevent too rapid loss of the gas, As oxygen is also essential for normal ripening, a fresh supply of air should be admitted each day. Temperatures favorable to the ripening process must be main- tained in the ripening room even when ethylene is used. Though explosive in the mixtures of 1 to 3 in the air, the gas is not dangerous or explosive in the low concentrations used in ripening tomatoes. YIELDS As stated in the introductory part of this circular, the yield to be expected from an acre of tomatoes depends largely upon the cultural practices of the grower. Variety and length of harvesting season are also important. Tomatoes produced for a spring shipping crop will yield only about three tons of salable tomatoes, to the acre, as in the Imperial Valley; but these fruits must be of high quality. For fall shipping a yield of four, five, or even six tons per acre is not unusual unless the season is shortened by frost. Canning tomatoes, however, are much more productive. Seven to twelve tons is the usual yield, and under favorable conditions much more than this has been reported. INSECTS3 Two types of tomato insect damage occur in California. Direct damage is done by insects feeding on the roots, foliage, or fruit ; while indirect damage results when certain insects spread disease. The role played by the latter is discussed in connection with diseases. Tomatoes are subject to insect attack during the entire life of the plant. The 3 The section on insects was prepared by Mr. F. H. Wymore, Associate in Ento- mology. !932] Tomato Production in California 35 extent of damage varies with the season and locality. The principal insects or insect-like pests which injure the plants directly are horn- worms, corn earworms, pinworms, cutworms, darkling ground beetles, vegetable weevils, and nematodes. Hornworms (Protoparce sexta and P. quinquemaculata) are large green caterpillars with a large curved spine or horn on the rear. They are about 4 inches in length when full-grown and have white stripes extending diagonally across the body segments and bright markings around the spiracles (breathing pores). These pests seem most abun- dant in the warmer sections of the state but are probably known by all who have ever grown tomatoes. The caterpillars attack the tender new growth of the plant, strip off great quantities of leaves and often gnaw into green fruit. There are two broods of the worms a year, but the late summer brood is usually the most serious. When full-grown, the large caterpillar burrows 1 to 4 inches into the soil, constructs an earthen cell, and changes into a large, chestnut-brown pupa about 2 inches long and % i ncn thick. The handle-like structure on the front end of the pupa case is the sheath for the long tongue or proboscis of the adult moth. During the summer the moths emerge from the pupa cases within a week or ten days, but after the first of October the majority of them remain in the soil until spring. The moths are large, having a wing expanse of 4 to 5 inches, and are mottled gray, with bright orange spots on each side of the abdomen. They are commonly known as sphinx moths because of their sphinx-like appearance when at rest, or as humming-bird moths because of their swift flight and their habit of hovering about certain large flowers at dusk to feed on the nectar. The moths appear in the spring in April and May and again in the summer in July and August. The spherical, smooth, green eggs, about Y 1G inch in diameter, are deposited usually on the upper surface of the outer leaves of the plants. The newly hatched young are less than Vi inch long, are pale yellowish in color, and have a very prominent black horn which is nearly as long as the caterpillar itself. Soon after they begin to feed, the color changes to green, and the worms increase in size very rapidly. Control. — Hornworms may be easily poisoned by dusting the tomato leaves with a, mixture of 1 part of calcium arsenate or basic arsenate of lead to 3 parts of hydrated lime. Very often the straight arsenicals are used when the dust can be distributed thinly and uniformly, as by some form of power duster. Several applications of the dusts may be neces- sary during the season. In localities where there is little atmospheric moisture present, a 70 per cent dust of either sodium or barium fluosili- 36 California Agricultural Extension Service t ClR - 66 cate has proved very effective. In small fields or gardens it is often practical to hand-pick and destroy the worms. The careful herding of a flock of turkeys through a heavily infested field has been reported as an effective means of control. Plowing and harrowing or disking the field late in the fall will destroy large numbers of the pupae. Corn Earworm (Heliothis ohsoleta) — While corn, especially sweet corn, seems to be the preferred host of this insect, it is often referred to as the tomato f ruitworm and is one of the most serious pests of tomatoes in California, During 1931 it was responsible for approximately 50 per cent loss in certain localities. In cotton growing districts, where this same species commonly attacks the green cotton bolls, it is known as the bollworm. It is also a serious pest on many other truck and field crops. The adult of this insect is a medium-sized, night-flying moth, with a wing spread of about l 1 /^ inches. Its body color varies from an olive buff to a dark reddish-brown, with a few characteristic brown or black markings. The tiny, delicately sculptured, dome-shaped eggs are creamy white when first laid and become a dirty white as the time for hatching approaches. A single moth may lay from 500 to 3,000 eggs. These are deposited singly, chiefly on the leaves of the tomato plants, but some- times on the fruit. The newly hatched caterpillar is about y 1Q inch long and rather pale in color, with a black head and with numerous black specks over the body. The larva sheds its skin (molts) five or six times during its active feeding period, which, during the summer, lasts about three weeks. After each molt the caterpillar becomes a little darker in color. After the fourth molt the color may vary considerably among individual caterpillars, including various shades of green, yellow, or pink, the longitudinal marks being usually more pronounced. A full- grown caterpillar may measure 1% to 2 inches in length. There are at least three broods of the worm each year. The first meal of the newly hatched caterpillar usually consists of the egg shell from which it just emerged, after which it may feed on the leaf on which the egg was laid. After feeding for a short time, the small caterpillar becomes restless, begins to wander from leaf to leaf, and may eventually come upon a fruit, into which it burrows. The majority of the worms enter the fruit at the calyx or stem end. In some cases the caterpillar may grow to maturity within a single fruit, but it may wander about over the vine and eat into several fruits. Not only does the worm hole render the fruit unmarketable, but decay usually follows. When full-grown — just before the sixth molt — the caterpillar ceases feeding and enters the soil to a depth of 2 to 4 inches near the base of 1932] Tomato Production in California 37 the plant. Here it forms a small earthern cell and changes into a small, brown, cigar-shaped pupa, about % i ncn long. During the summer the pupal stage lasts from 12 to 14 days, but after the latter part of September most of the pupae will remain in the soil all winter. Control. — Either sodium or barium fluocilicate dust, if thoroughly applied two or three times a season, to the inner portion of the vine and green fruit, should give fair protection from corn earworm. Lead or calcium arsenate, applied in the same manner, has given good results ; but being poisonous to man, these materials should not be applied after the fruit is half -grown. Thoroughly stirring the soil in the fall will destroy many of the overwintering pupae. Tomato Pinworm (Gnorimoschema ly coper sicella) . — This insect fre- quently causes considerable damage to tomatoes in California, particu- larly in the southern part of the state. It is also known as the eggplant leaf miner, and has been found in other members of the nightshade family. It derives its name " pinworm" from the fact that the entrance burrow of the newly hatched larva into the fruit is about the size of an ordinary pin hole. The full-grown larva is about % inch long and is purplish brown in color. The adult is a small, buff -gray moth with a wing expanse of % to % inch and with conspicuous black specks on the fore wings. The tiny white eggs may be laid singly or in clusters of rarely more than six on the leaves or on the fruit. The newly hatched cater- pillar is transparent white with a brown head. It often mines the leaves of tomato plants but outgrows this habitat within a few days, crawls out, folds a leaf, and then feeds within the fold. Two or three leaves may often be destroyed by one worm before it is full-grown. The worms do not confine their attack to the leaves, for, if the eggs are laid on a fruit, they usually bore into it. The larvae enter, as a rule, beneath the calyx or stem and continue to feed inside the fruit. Reports indicate that this pest may be responsible for the destruction of from 10 to 50 per cent of the fruits in certain localities. The mature caterpillars pupate in the soil. There may be several broods a year in localities where the tomato vines are not killed by frost. The potato tuber moth, Phthorimaea operculella, is commonly asso- ciated with the pin worm in many tomato fields. The moth is similar to the adult of the pinworm, but slightly larger. The caterpillars are usually lighter in color than the purplish brown pinworms, being a yellowish white, pinkish, or greenish, with a dark-brown head. They also have similar habits of mining the tomato leaves and stems and boring into fruit. 38 California Agricultural Extension Service t ClR - 66 Control. — No special method of controlling this pest has been developed ; but where poisons for the control of the corn earworm have been applied to the foliage and green fruit, especially in the earlier part of the season, pinworm damage has been greatly reduced. Cutworms. — The adults of the cutworm are practically all night- flying, rather somber-colored moths. Several species of these insects attack tomatoes. The eggs are laid in large masses on the host, usually in the early spring. The caterpillars have the habit of hiding in the daytime and are usually found singly or in groups of two or three just beneath the surface of the soil. They cut or gnaw off the young plants near the ground level; hence the name " cutworms. ' ' The worms are stout, soft-bodied, smooth, cylindrical, and 1% to 2 inches long; in color they vary from pale gray to dark brown or nearly black, often marked with spots or stripes. They normally feed on native plants but migrate to cultivated crops when the former source of food supply becomes exhausted. The cutworms are most active at night, but in the early spring they often emerge and feed during cloudy days. When full-grown, they burrow beneath the surface of the ground or under clods or other objects and pupate in a small earthen cell. There may be several broods a year. Cutworms usually pass the winter in the pupal stage, although a few caterpillars and adults may hibernate. Control. — Clean culture in the fall and plowing of infested fields to destroy the pupae will greatly reduce next year's broods. Early cultivation in the spring keeps down the food supply and destroys a great many overwintering caterpillars by starvation and exposure. If the cutworms occur in large numbers, a poison bran bait sown thinly over the ground before the plants are set in the field will kill most of the worms. A poison bait made up according to the following formula is effective : Bran (red bran preferred) 25 pounds Liquid sodium arsenite % pint Water approximately 4 gallons One pound of white arsenic or 1 pound of sodium fluosilicate could be substituted for the % pint of liquid sodium arsenite. White arsenic has in the past been most commonly recommended as a killing agent in poisoned bran mash but is often unsatisfactory because of imperfect mixing. Sodium arsenite is fully as satisfactory a killing agent as white arsenic and has the advantage of being easier to mix and is cheaper in cost. The liquid sodium arsenite can sometimes be procured on the market under the name ' ' weed-killer ' ' but it should not be con- fused with other chemicals used as weed killers. 1932] Tomato Production in California 39 Prepare the above material as follows : Mix the sodium arsenite with about 3 gallons of water. Slowly pour this liquid over the bran and stir thoroughly until an even mixture is obtained. Add only enough water to make a crumbly mass. The bait should be sown broadcast over the infested field at the rate of 5 to 10 pounds per acre. The bait is most attractive to the insects when fresh so the application should be made in late afternoon or early in the evening, as the caterpillars do most of their feeding at night. Caution. — This bran bait, being also poisonous to other animals and to man, should not be used in the vicinity of buildings where chickens or other fowls will have access to it. It may, however, be sown in pas- tures if it is scattered thinly and not put out in lumps or lines. The poison and poisoned bran mash should be kept out of reach of irrespon- sible persons. Armyworms. — These pests belong to the moth family (Noctuidae) and have a life cycle similar to that of cutworms, but because of the migrating habits of the caterpillars of certain species they are com- monly known as armyworms. The caterpillars of this group normally feed on native plants ; but if they have exhausted this food before they are fully grown, they will migrate in great hordes or armies to cultivated crops, devastating vegetation as they go. Several species of armyworms may attack tomato vines. Control. — Clean culture, summer fallow, or poison bran mash serve to control the armyworm. A poison bait, made according to the formula recommended for cutworms, and sown about in the field when the cater- pillars begin to migrate, will attract and poison countless numbers of them and may completely check their invasion. If the poison is not available, a trench plowed across their line of march, with a perpendicu- lar wall next to the field to be protected, will afford considerable pro- tection. If this barrier is properly constructed, the caterpillars cannot cross it and will gather in great masses in the trenches, where they may be easily killed by spraying with crude oil or kerosene. To be effective, the trenches require a certain amount of attention and repair. Darkling" Ground Beetles (Blapstinus sp.) . — Several soil-inhabiting species of small, bluish-black beetles, about a /4 inch long, frequently cause considerable damage to young tomato plants which have lately been set in the field. Injury is produced by the beetles girdling the plants at the surface of the soil. Control. — A poison bran mash, made according to the formula rec- ommended for cutworms, scattered over the ground a day or two before the plants are set out, will greatly reduce the beetle population. 40 California Agricultural Extension Service [&r. 66 This treatment will also kill a great many cutworms that happen to be in the field. If the stem of each plant is wrapped with a 3 or 4-inch strip of newspaper, so that there are two or three thicknesses for protection, it will be protected from the beetles and also be better able to withstand strong winds. Flea Beetles. — Several species of flea beetles attack tomato plants in California. The adults are about % 6 inch long, oval-oblong in shape, and reddish to dark brown or shining black in color. When disturbed they have the ability to jump like a flea, hence the name "flea beetles. " The beetles eat small holes in the leaves, giving them a distinct shot-hole appearance. The leaves of the young plants in the seed bed or in the field are frequently riddled by flea beetle attack, which greatly weakens the plants. In addition to the direct injury from feeding on the leaves, the beetles may spread certain tomato diseases. The larvae are small, white grubs that live in the soil and feed on the roots of many plants other than tomato. There are usually two broods a year. They pass the winter in the adult stage and use as hibernation quarters any trash or debris left about the field and along fence rows. Control. — The 4-4-50 formula of bordeaux, as used for fungus dis- eases, is an effective repellent for the flea beetles when thoroughly ap- plied to both the upper and lower surfaces of the leaves. The poison dusts which aid in the control of hornworms or of the corn earworm are also effective. Vegetable Weevil (Listroderes abliquus). — This insect attacks various truck crops in the San Francisco Bay region and at other points along the coast south to Monterey County. Damage to tomatoes is caused by the newly emerged adult weevils, gouging the stem or completely cut- ting off the young plants soon after they have. been set in the field. The weevils are always more destructive to tomatoes when the plants are set in soil on which a vegetable crop was seriously infested the previous sea- son. The adult of this insect is about % inch long, grayish-brown in color, with two pale oblique marks on the rear portion of the wing covers. Just behind each of these marks is a prominent tubercle. There is only one generation of the weevil each year ; and, though living adults may be found during any month, they hide away between June and Sep- tember. Control. — In the control of this pest, field sanitation is fundamental. The adult weevils hide away during the summer in undisturbed weedy areas in the fields or along fence rows and ditch banks ; a thorough clean- ing of these summer shelters will therefore greatly reduce the weevil population. Not only must the weeds be cut, but the soil should be made 1932] Tomato Production in California 41 entirely bare of all vegetation by the first of May. If possible, tomato plants should not be planted in a field that was infested with weevils the season before. Rotation of tomatoes with corn, cabbage, cauliflower, or celery, which are only slightly attacked, will also greatly reduce the Fig. 21. — Roots of tomato plant affected by nematodes- root-knot disease. (From Cir. 280.) -the weevil population. As a rule, sodium or barium fluosilicate, dusted on the foliage and about the base of the plants the same day they are set in the field, will protect them from weevil attack. It is a good crop insur- ance to dust, in this way, all tomato plants set in fields known to be in- fested, even though the weevils do not appear to be present at the time of planting, for they will probably migrate in from adjacent areas. 42 California Agricultural Extension Service [ Cir - 66 Nematodes or Eelworms (Caconema radicicola). — The garden nematode or eelworm is not an insect but a true roundworm, microscopic in size. This pest, a general feeder, causes a very common disease known as root-knot, which attacks many plants. On the fibrous feeding roots of tomato plants it produces gall-like swellings (fig. 21) which weaken and eventually kill the plant. The first indication that this pest is attacking the crop is the stunted, yellowed appearance of the plants in the field. One can make sure of the case by pulling up the plants and examining the roots. The nematodes are more likely to occur in sandy soil than in the heavier types. Control. — No satisfactory method has been developed for the control of this pest once it has become established in the soil. As nematodes are frequently distributed on seed potatoes or on rooted vegetable plants, every precaution should be exercised to prevent the disease from being brought from infested soils into the field and seed beds. Rotation, using resistant crops on infested soil for two or three years, has proved helpful in starving out the nematode. The Iron, Monetta, and Victor varieties of cowpeas and velvet beans have been reported to be resistant to nema- todes. Cereals, grasses, peanuts, soybeans, and onions have also shown a marked resistance. DISEASES Tomatoes in California are subject to many diseases, any one of which may result in considerable loss to the grower or shipper. The average annual loss from disease is not known ; but in certain localities such diseases as streak (tip blight, dieback, etc.), curly top, wilt, and late blight often cause financial loss. Tomato diseases are extremely dim- cult to control, and the symptoms of certain of them are so similar that it often is difficult to diagnose accurately the trouble in the field, particu- larly when a single plant is infected with verticillium wilt and streak or with curly top and streak. Tomato diseases may be grouped as follows : (1) parasitic, caused by a known disease-producing microorganism ; (2) nonparasitic, resulting from certain unfavorable climatic or environmental conditions, but non- infectious ; and (3) virus, induced by some unknown factor, but infec- tious. As the cause of parasitic diseases is understood, control is usually much simpler and more adequate than for virus or nonparasitic dis- eases, particularly when the life history of the parasite is known. In some cases the grower or shipper can regulate certain environmental conditions so that the noninfectious diseases are checked. With virus 1932] Tomato Production in California 43 diseases, however, control is exceedingly difficult, because these are dis- seminated by insects, and when a plant becomes infected there is no known method of preventing its spread throughout the whole plant sys- tem. Such infected plants, unless removed and destroyed, serve as cen- ters of infection in the field. It is also significant that certain tomato virus diseases may be spread to potatoes, sugar beets, and various other truck crops and weeds. The principal diseases affecting tomatoes are as follows : Fusarium Wilt {Fusarium ly coper sici) . — Fusarium wilt is one of the most widespread diseases of the tomato, first reported in 1882 and Fig. 22. — Symptoms of fusarium wilt in an advanced stage. The plant appears to have suffered because of lack of sufficient water: the lower leaves are yellow, and the younger leaves have turned brown and become brittle. (From C'ir. 263.) particularly severe in the interior valleys of California where several tomato crops are grown in succession on the same soil. In 1922 and 1923, this wilt was prevalent in the Santa Clara and San Fernando valleys and in Orange County. The disease may be noticed on seedlings soon after they are trans- planted ; in that case, infected plants wilt, turn yellow, and soon die. If infected late, the plants become stunted, the lower leaves become yel- low and die, the younger leaves wilt as though suffering from inadequate water (fig. 22), and the woody area in the stem between the pith and bark assumes a dark-brown discoloration, which in some cases extends into the side branches, through the pedicel, and even into the fruit and seed. Thus the disease mav be seed borne into disease-free localities. 44 California Agricultural Extension Service [ Cir - 66 The causal agent, Fusarium lycopersici, may be classed as a soil fun- gus ; that is, it may persist in the soil for several years even though a tomato crop is not grown during that time. Infection takes place through the roots ; and the disease is spread in the field by means of irri- gation water, animals, implements, etc. The organism grows most rap- idly at temperatures between 24° and 28° C (75° and 82° F) and seems to be most severe in the lighter, well aerated, and well drained types of soils. Control measures vary according to the condition of the field. If the disease has never been seen in a given field, it is wise to use such prevent- ive measures as buying disease-free plants, seed disinfection, and disin- fection of the soil in the plant bed. After the disease becomes established in the field, the only alternative is the use of resistant varieties. As many such have been developed by selection or hybridization, seed is now gen- erally available. For California, the two wilt-resistant varieties best suited for use are the Marglobe and Norton, described elsewhere in this circular. Other resistant varieties are Marvana, Columbia, Louisiana Pink, Louisiana Red, Norduke, Arlington, Kanora, Livingston's Globe, Invincible, Tennessee Beauty, Marvel, Pritchard, Delaware Stone, and Duke of York. Two new resistant varieties named Blair Forcing and Lloyd Forcing, recently developed in Illinois, are especially suited to greenhouse propagation. Verticillium Wilt (Verticillium albo-atrum) . — The organism of Verticillium wilt is now known to be also the cause of black heart of apricots and blue-stem of raspberries, such evidence indicating that the disease in tomatoes is not new to California and that some diagnoses may have been incorrectly attributed to fusarium when verticillium was the cause. The similarity of symptoms produced by these two organisms often makes positive identification very difficult in the field ; but in the laboratory, such identification is comparatively easy. In California the history of the disease in tomatoes most likely parallels that in the apricot. Symptoms develop both on the roots and on the aboveground portion of the plant. Large, black, irregular cankers develop both on the large fibrous roots and on the taproots, while a brown discoloration is mani- fested within. Similar discoloration may be found inside the stem above- ground. The leaves of infected plants become limp during the heat of the day and partially recover during the night, while the tender tips of the shoots may droop and finally wither. Usually the lower leaves are the first to manifest symptoms ; after their death, the new leaves which form are stunted and dull rather than bright green in color. In some instances only one side of the plant is infected, but more commonly the whole plant dies prematurely. 1932] Tomato Production in California 45 Verticillium albo-atrum grows most rapidly in culture at tempera- tures between 21.2° and 25° C (70° and 77° F), slightly lower than the optimum for Fusarium lycopersici. This relation may explain the pre- valence of verticillium wilt in the coastal sections, although the disease has been found in the San Joaquin and Sacramento valleys. Fig". 23. — Symptoms of late-bliglit infection on tomato leaf. The spots are at first water-soaked, later becoming greenish-brown or black. A white mold forms on the under surface, from which the disease spreads to other foliage. (From Bui. 239.) No adequate means of control is known, but severely infested soil had best be planted with some crop other than tomatoes. Oregon experi- menters recommend that susceptible crops be grown on infested soil only once in four years. In general, cereal and forage crops are not attacked by verticillium wilt. Late Blight (Phytopthora sp.). — The disease known as late blight occurs annually in the coastal districts of southern California, and is often prevalent inland in San Diego, Ventura, Los Angeles, and Orange 46 California Agricultural Extension Service [ Cir - 66 counties. In addition to loss in the field, infected fruits often decay while in transit to the eastern markets. Large water-soaked blotches, varying from greenish-brown to black in color, first appear on infected leaves (fig. 23) ; later, dark-colored lesions form on the stem. During moist weather a fine, white, downy mildew appears on the lower surface of infected leaves, where thousands of spores are formed which are capable of infecting healthy foliage when spread. Fruits are apparently susceptible to attack (fig. 24). Decay Fig. 24. — Symptoms of late blight on tomato fruit. Decay usually starts at the stem scar. Small, greenish-brown blotches later enlarge and become dark brown. The interior tissues become water-soaked and soon decay. Often a white mold develops on the surface. (From Bui. 239.) usually starts at the stem scar, the first visible symptom being a small, greenish-brown blotch less than V4 i ncn m diameter. Later the spots become greenish-brown or brown ; the interior tissues become water- soaked and brown and soon decay. If infected fruits are kept in a moist, well-protected place, a downy mildew develops on the surface. The prevalence and destructiveness of late blight are closely corre- lated with weather conditions favorable for growth and dissemination of the causal organism. Cool nights (50° to 60° F) and moderately warm days (60° to 75° F) during seasons when there is an abundance of atmospheric moisture (fogs or rains) are especially favorable for the development of the disease. Such weather conditions prevailed during the late fall of the years 1926, 1927, and 1928 in southern California, when the disease was severe. In 1929, when the weather was warm and dry and fog uncommon, late blight loss was very light. 1932 ] Tomato Production in California 47 Late blight may be prevented by spraying or dusting with a copper- containing fungicide. Whether spraying or dusting is practiced will depend largely upon the equipment available, the weather, and the topography of the land where the crop is growing. If a wet spray is used, a 4-4-50 bordeaux mixture is recommended. This is prepared by dis- solving separately 4 pounds of copper sulfate (bluest one) and 4 pounds of unslaked lime (6 pounds of hydrated lime). Each solution is diluted to 25 gallons, and the two are then poured together, making 50 gallons of spray material. Special spraying machines adapted for spraying two or three rows at a time are used ; they should have three nozzles for each row. Tomatoes should be sprayed at a pressure of at least 100 pounds per square inch, to insure that all parts of the plant are reached by the spray. Several applications are necessary in order to keep new growth protected from infection ; the first of these should be made at the first evidence of disease in the field and should be continued at intervals, ac- cording to the air temperature and humidity. The amount of spray solution required for each application will vary from 100 to 300 gallons per acre, according to the size of the plants and the width of the rows. If a dust mixture can be more conveniently applied, copper-lime dust is recommended. This fungicide may be bought already prepared, or it may be made at home by mixing together 15 pounds of monohydrous copper sulfate and 85 pounds of hydrated lime. The ingredients can best be mixed in a revolving wooden barrel. The dusting schedule is the same as for spraying. Bacterial Canker (Aplanobacter michiganense) . — Bacterial canker was first found in California in 1928 in Stanislaus and Ventura coun- ties. In 1929 it was seen in Sacramento, San Joaquin, and Santa Clara valleys as well as in Monterey and Ventura counties. Although the dam- age done by it in California is not yet alarming, one should note that in some fields in Georgia in 1928 the loss was 85 per cent. In 1928 there was 25 per cent loss from canker reported in some fields in California. The disease was more widespread in 1930 and 1931 than in 1929 — a fact indicating that preventive and control measures should be taken in order to prevent its general occurrence and spread. Canker is rarely found in the seed bed while the plants are young, although occasionally plants die of it before transplantation. In the field the first sign of the disease is a downward curling of the lower leaves, which soon wilt and die; then follow similar symptoms in new growth in the infected plant. The stems and petioles remain turgid, while the leaflets droop, turn brown, and die, hanging from the petiole, which remains attached to the stem. On the stems, canker symptoms are 48 California Agricultural Extension Service [Cm. 66 manifested as yellowish-white streaks, which frequently become gray- ish-brown. These lesions usually appear on the tender upper part, where infection has reached the bark and lies close to the surface. When these streaks crack open, the characteristic cankers are formed. The interior of diseased stems is discolored between the pith and wood, these discol- ored tissues becoming" mealy, so that the wood separates easily from the pith. At first such discolored areas are yellow, but with increasing age they become reddish-brown. Infection is usually not evident in the stem at the soil surface. The bacteria that cause canker move through the stems out into the fruit and sometimes become lodged inside the seed coat, without causing any visible damage to the fruit. In other cases, if the fruits are heavily infected when young, they become spotted, stunted, and distorted. In- fected seeds usually appear normal but sometimes have a brown spot on the surface. In Ohio the canker bacteria have been found capable of living in the soil. To date no plant other than the tomato has been found susceptible to bacterial canker. In the light of our present knowledge of the cause and nature of bac- terial canker, the following recommendations may be observed with profit : 1. Select seed from a field that is free of the canker disease. 2. If plants are imported, make sure that they were produced from canker-free seed. 3. Disinfect the seed if plants are not bought or furnished. Disinfec- tion is accomplished by soaking the seed in a 1-3,000 solution of mercuric chloride, prepared by adding 1 gram of mercuric chloride (corrosive sublimate) to 7 pints of water. After soaking for five minutes, the seed should be washed in clear water before being planted. Mercuric chlo- ride is a deadly poison. It is also corrosive and should not be used in metal containers. 4. Use new soil in the plant bed each year, being sure that such soil has not recently produced tomatoes. If more convenient, the plant-bed soil may be disinfected with formaldehyde as follows : add 1 pint of for- maldehyde to 50 pints of water and saturate the well-loosened soil. Cover with burlap or similar material. After 48 hours repeat the process. Al- low ten days to two weeks for the formaldehyde fumes to escape before planting the seed. 5. Grow tomatoes in the same field only once in three or four years. Nailhead Spot (Macrosporium sp.) — This disease is so named be- cause the characteristic fruit spotting resembles in size and shape the head of a nail. Infection in the field usually first appears on the young 1932] Tomato Production in California 49 leaves in the form of small brownish spots, which, however, enlarge rapidly and soon develop concentric rings, outside of which the tissue becomes yellow or brown. Often several spots coalesce and obscure the regularity of the individual spot. The stems of plants attacked in the plant bed may be partially or completely girdled with a hard, shiny, brown lesion which results in stunting. If such stunted plants are set in the field, partial recovery may result ; but the plant never produces a normal yield. On the fruit, the first sign of infection is manifested in the form of minute, light-brown discoloration of the skin. Later the spot enlarges, and becomes depressed, the outline becomes more definite, and the color changes to dark brown, during which time the interior of the spot fades into a dull, grayish-white color. In the center of the spot the spores of the causal organism develop, and with proper environmental conditions they are spread to and infect other fruits. Severe injury by nailhead spot may be partially prevented by weekly application of bordeaux mixture (4-4-50). The wet spray has been found superior to dusts. In Florida the Marvel, Norton, and Marglobe have proved comparatively resistant to this disease ; and, as these varie- ties are also resistant to f usarium wilt, their use is recommended in sec- tions to which they are climatically adapted. Damping-Off (Pythhim, Rhizoctonia, etc.). — Damping-off is en- countered principally in the plant bed, where plants become infected at the soil surface and either fall over and die or become severety mal- formed and stunted. The first symptom is a slight drooping of the cotyledons at their tips and a general lack of turgidity. Soon the stems appear water-logged at the soil line, and the mycelium of the causal or- ganism becomes evident there as a white or grey mold. Damping-off is favored by humid conditions and inadequate ventilation. It is often advisable to cover the soil in the plant bed with a layer of sand about *4 inch deep. This sand dries rapidly after watering and thus makes en- vironmental conditions less favorable for infection. Because the organisms which cause damping-off are commonly found in the soil, the only sure means of control is soil disinfection by steam or chemicals. The latter may be applied in either dust or liquid form. If liquid is used, follow the recommendation outlined for control of bac- terial canker. Recent work in Ohio has shown that a formaldehyde-dust mixture is effective. This dust is made by mixing 15 parts by weight of commercial formalin (40 per cent formaldehyde) with 85 parts of an inert substance such as kaolin, diatomaceous earth, or infusorial earth. The resulting dust mixture is then screened, applied to the soil in the propagating bed at the rate of 2 ounces per square foot, and worked into ' tl ( 50 California Agricultural Extension Service [ Cir - 66 the soil to a depth of 3 inches. Seed is planted immediately, and the soil is thoroughly watered. Although this practice has not been tried experimentally in California, growers could wisely use the method in an experimental way. One preserving company has used this dust on a large scale for control of damping-off . Blossom-End Rot. — The disease known as blossom-end rot is wide- spread and may be found wherever tomatoes are grown. To date no causal organism has been found responsible, and the trouble is generally believed to be induced by certain environmental conditions. Usually the disease is prevalent only during the warmer parts of the tomato growing Fig. 25. — Symptoms of blossom-end rot on tomato fruits. (From Bui. 239.) season. The theory is that in cool weather the plants become well estab- lished and grow normally, with the evaporation taking place slowly ; but with abrupt rise in air temperature, more moisture is lost than can be taken up through the roots. Then the water from the fruits is withdrawn from the cells farthest from the stem, and small brown spots appear as a result at the blossom end of the fruit. This continued evaporation causes the spot to enlarge and sometimes involves most of the fruit. The spots are at first brown, later becoming black ; or, when a saprophytic organ- ism gains entrance, decay results (fig. 25). Infected fruits are usually flat at the blossom end. It has been suggested that with abrupt or even gradual rise in air temperature, additional water should be used to supply the demands of the plants. Tomato Virus Diseases. — Unlike such diseases as wilt, blight, and canker, the tomato virus diseases are of unknown cause. They are infec- tious, however, and hence are said to be induced by an infectious princi- ple, termed a virus. Although potato aphis and beet leafhoppers are chiefly responsible for the spread of these diseases other insects may 1932] Tomato Production in California 51 also carry the infectious principle on their mouthparts. In California there are at least three virus diseases of the tomato, two of which have caused considerable loss during the past 15 years. Mosaic. — Tomato mosaic is commonly found wherever this crop is grown, causing as high as 50 per cent yield reduction in certain localities. It is widespread in California, although the average yield reduction for the state is probably less than 8 per cent of the annual crop. The disease has also been found on many weeds, some of which are perennial ; and the virus lives in the rootstocks of the latter when frost kills the foliage. Tomato mosaic is known to affect eggplant, pepper, petunia, ground cherry (several species), and horse nettle, and may be spread from all these to tomatoes. In Florida, 35 host plants of tomato mosaic have been found. Mosaic symptoms vary with air temperature, sunlight intensity, age of plants, and rate of growth, but develop only on the parts of a plant that are in a growing condition at the time of infection or which develop subsequently. After a plant is infected, the virus spreads throughout the whole plant system. Infected plants never recover, although with advancing age, accompanied by certain environmental conditions symp- toms may partially or completely disappear. Characteristic symptoms develop on the leaves and fruit. Several types of distortion may develop on the leaves, as follows: mottling, crinkling, dwarfing, tip rosetting, and a condition known as ' ' filiform leaf. ' ' Mottling results in irregu- lar areas of light green color in a normal leaf. From this condition symptoms range through crinkling and tip rosetting to dwarfing. The filiform type, of less general occurrence, is manifested by long, slender, irregularly notched leaves. Blossom development on a plant so infected is impeded. The result is a witch's broom effect which produces little or no marketable fruit. Fruit borne on mosaic-infected plants is often deformed, rough, puffy, and usually unsalable. Prevention of the serious loss caused by mosaic involves eradication of host plants in or near the plant bed and frequent dusting of the seed- ling plants in the plant bed with nicodust, Plants are often produced at a time when aphis are numerous and when many of the perennial host plants of mosaic are infected. If such host plants are allowed to grow near the plant beds, there is always danger of infection. After infection has occurred in the plant bed, little profit is gained by roguing or by aphis control, because a few aphis may carry the virus throughout the bed. The juice of infected plants is so highly infectious that infection may take place during the necessary cultural operations, such as cultiva- tion and watering. After the plants have been set in the field, it is too 52 California Agricultural Extension Service [ Cir - 66 late to attempt control. Probably the most important means of prevent- ing mosaic infection is to destroy all susceptible vegetation near the plant beds. Streak. — A particularly malignant disease known as streak com- monly occurs on tomatoes growing in the greenhouse, but is often found in the field. As with mosaic, streak-infected plants manifest foliage mottling and, in addition, brown dead streaks on the stems and leaves ; the growing tips are blighted, and the fruit is blistered, misshapen, with an irregular surface pattern of brown, dead tissue. Streak results when a healthy tomato plant is inoculated with a mixture of juice taken from Fig. 26. — Proof that the tomato curly-top disease is carried by beet leaf- lioppers. Row 3 had its plants exposed to infective hoppers three days before transplanting. Rows 2 and 4, checks, remained almost entirely healthy. (From Cir. 263.) a mosaic-infected tomato plant and either a healthy or a mosaic-infected plant of the Irish potato. Preventive measures for tomato streak are identical with those outlined for mosaic; in addition, care should be exercised to locate the plant beds at some distance from potato fields. Curly Toy. — Tomato curly top (yellows) is probably the most serious virus disease of this crop in California, varying during a period of years in the actual loss caused. Recently, this variation has been definitely correlated with the incidence of sugar beet curly top, as these two dis- eases are induced by the same virus (fig. 26). Heavy losses are often common to the tomato crop in the Sacramento, San Joaquin, and Salinas valleys, with less severe infestation in the coastal sections. During some seasons, curly top has been prevalent in the interior region south of the Tehachapi range. Losses may vary from a trace to almost complete crop failure. Tomato curly top is spread from diseased to healthy plants by the beet leafhopper, Eutettix tenellus, and in years of severe outbreaks of 1932] Tomato Production in California 53 the disease its severity varies according to the number of leafhoppers that invade the cultivated regions from different parts of a natural breeding area. The direction of the wind at the time of the hopper flights is believed to be a factor controlling the amount of infection in the mi- ^. Fig. 27. — Symptoms of tomato curly top, probably the most serious disease known in California. Note the inward rolling of the individual leaflets, the downward curving of the petiole and midrib, the erect habit of growth, and the stunted condition. On infected plants the leaves become crisp, yellow, and thickened; and a purple discoloration is evident on the leaf veins and stems. gratory regions of the insect. In 1927, migration from the San Joaquin Valley was largely westward into the fog belt, where about five per cent infection resulted ; at the same time less than one per cent was found in the Sacramento Valley. In addition to tomatoes and sugar beets, many other economic plants have been experimentally infected with curly top, or naturally infected plants have been proved susceptible by inoculations from them to sugar beets. Some of the most common of these are : beans, spinach, the cucur- 54 California Agricultural Extension Service t ClR - 66 bits (cantaloupe, squash, cucumbers, and watermelons), peppers, and horseradish, although many others might be listed. Symptoms of tomato curly top (fig. 27) are fairly distinct in both the greenhouse and the field. The principal symptoms in the field are (1) an inward rolling of the leaflets along the midrib; (2) downward curving of the petioles and midrib, giving the leaf a drooping but not wilted ap- pearance; (3) thickening, crisping, and yellowing of the leaves; (4) stunting; (5) erect, rigid habit of growth ; and (6) purple discoloration of the leaf veins and on the stems. Symptoms in the greenhouse are similar ; but, in addition, transparent venation and warty protuberances may develop on the leaves. To date there is no adequate means of control or prevention of to- mato curly top. Progress in selection for resistance has apparently been made. The varieties Dwarf Champion and Ked Pear are known to pos- sess some resistance, and selections within these varieties as well as crosses of these with more important commercial varieties are being made and tested for resistance and adaptation. Perhaps the time of planting might be so regulated that the plants will be as large as possible before the flights of leafhoppers begin. Some benefit has been obtained by shading the plants with temporary tents which somewhat protect them from insect visitation and create conditions less favorable for the development of the disease. The expense of shading, however, would probably seldom be justified. SEED GROWING Although comparatively few tomato growers now select and save seed for their own use, an improved acclimated strain can sometimes be developed by home selection of seed. Although tomatoes are very largely self-pollinated, some crossing does take place when different varieties are grown near each other. The amount of crossing varies from 0.2 to 5.0 per cent, according to the variety and on the number of insects (mainly bumblebees) which visit the flowers. Accordingly, the seed plot should be isolated from other varieties. Many varieties contain plants varying a great deal in vigor and yield, as well as in quality and type of fruit. Some seed stocks are actually mixed, containing plants of poor type, of low yield, or of different varieties. The procedure recommended is to mark certain plants that show vigor, health, and earliness about the time the fruit 1932] Tomato Production in California 55 4lt^* Fig. 28. — Cross sections of fruit of the San Jose Canner variety. A, large meaty core with small cells — a good type. B, cells too large — a poor type. 0, many abortive cells, characteristic of rough fruit — a poor type. D, large, hard, white core in center of fruit. (From Hilgardia, Vol. 2, No. 2.) Fig. 29. — "Puffy'' fruit. Note the air spaces between the seed jelly and the outer wall. This trouble is partly a hereditary variety characteristic and partly the result of cultural conditions. (From Hilgardia, Vol. 2, No. 2.) 56 California Agricultural Extension Service [ Cir - 66 begins to ripen. The pickers are then instructed to take no fruit from the marked plants. A second inspection, two or three weeks later, will enable one to judge of the productivity, quality, and type of fruit. The fruit should have desirable internal characteristics (fig. 28) and should not be "puffy" (fig. 29). Seed is saved from the plants which seem desirable from this standpoint. It is best to save the seed from each plant separately and to plant one row in the field the next year with seed from each plant. The remaining seed from the selected plants can be mixed and used for the main planting. From the best row of the second year, seed is saved in sufficient quantity for the entire planting the third year. Practically all the benefit derived from selection is apparent in the tomato the first year after the selection is made. Selec- tion simply isolates the best qualities present in the original variety, and the improvement over the average is usually sufficient to make the practice profitable. Selection should, however, be continued from year to year to eliminate any degenerate plants and to preserve and improve, if possible, the qualities of the original selection. Indiscriminate selec- tion of good fruits without reference to vigor, health, yield, and type of the plant from which the fruit came will not result in much improve- ment, for even poor plants may produce a few good fruits. There are generally no hereditary differences in seed from early or late fruit, or from large or small fruits on the same plant. Generally speaking, the ideals in selecting tomatoes are as follows : first, a vine that is large, vigorous, free from disease, and able to pro- duce a large yield of fruit at the season when it is particularly wanted ; second, fruit of the size, color, and shape desired for the variety ; third, fruit that is smooth in contour and free from defects such as corky spots, large scabs, or ' ' cat faces. ' ' When cut transversely, the tomatoes should show well-filled cells and freedom from greenish spots and hard white ones. Fruit from which seed is to be saved should be allowed to ripen fully on the vine. When large quantities are to be saved from a number of plants, the ripe fruit is gathered at intervals and dumped into wooden barrels, where it is pounded into a pulp ; or it may be pulped by pressing through a grinder. Water should not be added : there will be sufficient juice in the pulp to insure fermentation. After the pulp has stood until the gelatinous mass surrounding the seed is well decomposed, water is added. Vigorous stirring facilitates separation of the seed. The well- filled seed sinks to the bottom, while the poorly filled seeds, skins, and pulp rise to the surface, where they can easily be skimmed off. The seeds are thoroughly cleaned by several successive washings, after which they 1932] Tomato Production in California 57 should be removed, spread in thin layers on wire or cloth screens, and placed in the sun or elsewhere to dry as quickly as possible. In cleaning seed on a larger scale, a flume with catch basins is used to separate seed from pulp, and the seed is dried in rotating cylinders through which a current of hot air is driven. ACKNOWLEDGMENTS The writers wish to express their appreciation to the Farm Advisors and Agricultural Commissioners for their cooperation in furnishing the data on acreage, varieties, yields, etc. of tomatoes in their respective counties in response to a questionnaire sent out in June, 1931 ; to Mr. D. P. Wheeler, Agricultural Commissioner of Merced County, for data regarding the growing of staked and pruned tomatoes ; to the Fresno Republican for permission to reproduce figure 3 ; and to Mr. M. Shapo- valov, U. S. Dept. of Agriculture for the use of figure 27. The writers also wish to thank Mr. F. A. Dixon of the Canners League of California for criticizing this manuscript, and Mr. M. Shapovalov for criticisms of the portion of this circular dealing with diseases. 16m-10,'32