UNIVERSITY OF CALIFORNIA AGRICULTURAL EXPERIMENT STATION ~*. . -^- ~~ .«._._..._....- BENJ. IDE WHEELER, President COLLEGE OF AGR CULTURE ^w w.-^..- wr "«n,v« t writ. THOMAS FORSYTH HUNT, Dean and Director BERKELEY H. E. VAN NORMAN, Vige-Director and Dean University Fart." School CIRCULAR No. 199 May, 1918 ONION GROWING IN CALIFORNIA By STANLEY C. ROGERS CONTENTS PAGE Introduction 1 Onion Producing Sections in California 2 Cost of Production, Yields and Prices Received 2 Cultural Requirements 3 Soil 3 Moisture 3 Climate 3 Preparation of the Soil 3 The Onion as a Market Garden Crop 4 Methods of Propagating 4 Planting 5 Transplanting to the Field (> Irrigation 8 Cultivation 10 Breaking Down the Tops 10 Harvesting 11 Storage 13 Onions as a Truck Crop 14 Varieties 13 Onion Seed Production 17 Crop Troubles 20 Onions have always been one of the most important vegetable crops in California and as early as 1874 there was considerable interest in their production. From the years 1900 to 1915, inclusive, the amount planted in this state varied from 2500 to 4500 acres per year. As reported by the Bureau of Crop Estimates, the onion acreage in California for the years 1916 and 1917 are as follows : 1916 1917 Bermuda onions 570 1,435 Midsummer or intermediate 1,000 1,500 Late or storage onions 4,300 9,000 According to the estimates of the U. S. Department of Agriculture, California was the largest onion-producing state for the years 1916 and 1917. ONION-PRODUCING SECTIONS OF CALIFORNIA San Joaquin, Contra Costa, Sacramento, Imperial, Riverside, and Santa Barbara counties are the principal onion-producing sections in California. Aside from these, onions are grown throughout the entire state, and there is probably not a market garden in California which does not produce this crop at some season of the year. COST OF PRODUCTION, YIELDS, AND PRICES RECEIVED The cost of producing onions is dependent upon the character of the soil, method of cultivation, season, acreage, and experience of the grower, and varies from $70 to $125 per acre, with an average cost of $80, exclusive of land rental and fertilizing. The following cost per acre data have been secured from several experienced growers, and at the University Farm garden : Plowing 12 in. deep $3.00 Harrowing and packing 1.00 Seed 4.00 Growing plants 1.00 Transplanting 20.00 Irrigating (four times) 10.00 Hoeing and weeding 25.00 Harvesting and sacking 20.00 $84.00 The yields of onions vary from 50 to 700 sacks per acre, a sack of onions weighing from 100 to 105 pounds. Where this crop is grown by the intensive method, production varies from 300 to 500 sacks per acre, with occasionally larger yields. Where the onions are produced on large tracts, the normal yield is from 200 to 300 sacks per acre. The price of onions varies more than any other vegetable. As a rule, the highest prices are paid during the winter and spring, and the lowest during mid-summer and fall. Occasionally this vegetable will bring 35c to 40c per sack, while during other years the price is from $6 to $8 per sack. The average price for the summer crop varies from 75c to $1 per sack, and the winter and spring crop will generally command from $1 to $3 per sack. As a large part of the California crop is shipped to states east of here, the winter and spring quotations are dependent largely upon the supply in the eastern store-houses, especially in those of Texas. CULTURAL REQUIREMENTS Soils. — The choice of suitable soil is one of the fundamental factors in onion growing. The soil best adapted for this crop is one which is retentive enough under cultivation to keep sufficient moisture about the roots, and friable enough to be easily cultivated and to allow the proper expansion of the bulb. It should be rich in organic matter and the minerals, for it is impossible to grow a satisfactory crop of onions on a soil of poor quality. A heavy adobe or clay is very expensive to work and is so compact that it is sometimes impossible to produce onions of desirable size and shape. Soils of a very sandy nature are liable to be deficient in the essential food materials, and it is difficult to retain sufficient moisture for the plants, even where irrigation is practiced. When growing this crop for the early spring markets, the ideal soil will be lighter in character than one producing fall crops. The most desirable class of soil is either a light loam or peat, rich in plant food and retentive of moisture. The most undesirable soils are adobe and coarse sand or gravel. Moisture. — Onions require large amounts of soil moisture from the time of planting until they are maturing and the relation between the moisture supply and the production of onions is vitally important. As this is one of the most shallow-rooted vegetables, the field practice should be such that the moisture will be retained within one to three inches of the surface throughout the entire growth of the plant. The plants will stand an excessive amount of water with less injury than when the supply is deficient. From the time the crop is beginning to mature until it is harvested, the amount of soil moisture necessary is much smaller than during the other stages of growth, as an over- abundance during this period will produce onions which are watery, and are of poor keeping quality. Climate. — The onion is one of the most hardy vegetables grown and is so resistant to cold that it is produced during the season of the year when many of the other vegetables would be killed. If given plenty of moisture it will endure the heat well, although it grows most luxuriantly in moderate temperatures. At the University Farm gar- den, during the winter of 1916, small onion plants in the seed-beds withstood a temperature of 20° F. apparently without injury. PREPARATION OF THE SOIL The preparation of the field and its condition at planting is often the direct cause of the success or failure of the entire crop. The first essential requirement is that the field be entirely free from weeds, and at the time of planting the earth should be moist up to the surface and in as fine a physical condition as possible. The experienced grower realizes the importance of a good seed bed so that the field is worked very carefully previous to planting. A large percentage of the crop is grown in California without fertilization. This is especially true throughout the delta sections. When the crop is being grown in the market garden, a large quantity of manure is used a short time before planting, applications being- made at the rate of from fifteen to thirty tons per acre. The manure should be put on long enough before planting so that it may be com- pletely rotted by the time the field is to be used, and it is preferable to apply well-rotted manure rather than that which is hauled directly from the stable, for otherwise the litter which it contains will have a tendency to keep the soil open, allowing it to dry around the young tender plants; the liability of weed infection is much greater in case of fresh manure than with well-rotted manure. It is not customary to plow under the manure as deeply as would be advisable in growing other vegetables. THE ONION AS A MARKET GARDEN CROP Method of Production. — When growing onions in the market garden, the seed is generally sown in seed beds and the young plants transplanted to the field. This method has two advantages over seed- ing in the field ; onions which are transplanted will generally produce a more even crop and the stand will be more uniform than if the seed is sown directly in the field. The crop will occupy the field one to two months less time, which is of considerable importance where high rental is paid, as it may give the grower a chance to produce one more crop than he otherwise could. There are two forms of seed beds used, open beds and hotbeds. The former, which are the most common, are made three to five feet wide and eight to twelve feet long ; a ridge of earth six to eight inches high and one foot in width at the base is made between the beds in order to facilitate irrigation. A ditch should be made between each two rows of beds. If the beds are to be sprinkled instead of flooded, the ridges need not be as large as when the former method of irri- gation is used. The location of these beds should be such that they may be irrigated easily and sheltered from the winds. The soil should be of light character so that it will not pack when wet. No water should stand around the plants during the rainy season. Planting. — The time of planting is dependent upon the section of the state, in which the garden is located, the variety planted, and the season at which it is desired to have the crop mature. In central California the seed is generally planted during September for the early spring onions, or from November until February, inclusive, for the later crops. The seed may be sown either in drills, having the rows from two to four inches apart, or broadcast, covering with one-half inch of soil. From one to two pounds of seed will grow a sufficient number of plants for one acre, providing the seed is of good quality. If it is desirable to fertilize the beds, finely screened stable manure may be used and should be applied long enough in advance of plant- ing so that it will be completely rotted before sowing the seed. Fig. 1. — Onion seed beds containing plants six weeks old. Under ordinary conditions the plants will be ready to set in the field from six weeks to two months after the seed has been sown. The beds should be watched very carefully and the moisture should be continually kept at the surface. During the early fall the beds are often irrigated three or four times a week, especially during the warm weather. When the plants are from one-fourth to one-half an inch in diameter at the surface of the soil, they are ready to be transplanted to the field. At the University Farm garden 1555 square feet of seed beds, including irrigation ditches, produced a sufficient number of plants for one acre in the field. During the mid-winter or early spring planting, the hotbeds may be used in preference to the one above described. The method of planting and care of the plants is the same for both types of beds. Transplanting to the Field. — The transplanting is done between November and March, inclusive, the exact time depending largely upon the date of planting the seed, variety and the local climatic conditions. " ■■■■■-■:"■ ■;::;;: ;:~& Fig. 2. — Digging and trimming onion seedlings preparatory to transplanting. One week before the plants are to be removed from the seed beds the watering should be discontinued in order that they may be well hardened. A few hours before digging, the plants should be thoroughly irrigated. They may be dug with the aid of a shovel or spade and in such a manner that at least two inches of the roots will remain on the plants. After digging, the plants are separated from each other and laid in rows or piles. The tops should be cut off to the end of the central blade and the roots trimmed until they are one-half inch to one inch in length. From the time they are removed from the beds until they are transplanted, the seedlings should be covered in order that as many of the small fibrous roots as possible may be preserved. Fig. 3. — Plant properly trimmed for transplanting. The field may be divided into sunken beds, setting the plants three or four inches apart in rows twelve to fifteen inches apart. The size of the beds is determined by the slope of the land, but under ordinary conditions each is twenty feet square. When the cultivation is to be performed by horse-drawn imple- ments, the rows should be as long as possible. The plants are set in the bottom of furrows two to three inches deep and the roots may be covered by raking the earth over them. The transplanting is done most economically by three men, two placing the plants and the third covering. Under ordinary condi- tions it will take three men three days to plant one acre, provided they do not have to pull their plants. CARE OF PLANTS IN THE FIELD Irrigation. — A large percentage of the onions grown in California require irrigation. The exact time for applying the water is depen- Fig. 4. — Setting onion plants in field. dent upon the season of the year, and the character of the soil. If the plants are set in the field in November, the soil should be thor- oughly irrigated before planting, provided there has not been sufficient rainfall. After the plants have started to grow they should never be allowed to suffer from lack of moisture, for if their growth is retarded they are liable to go to seed or become scullions instead of producing marketable bulbs. The number of irrigations which the field should receive will vary from two to five, the exact number being largely determined by the rainfall and season. In irrigating the field, care should be taken not to allow the water to pass over the ground too rapidly ; it is better to use a small stream, Fig. 5. — Plants set in sunken beds. Fig. 6. — Setting plants in long rows to permit cultivation by horse-drawn implements. 10 allowing the moisture to seep into the soil thoroughly, than to use a large swift running stream. The soil should be kept continuously moist up to one to three inches from the surface. When the plants are starting to mature the watering should be discontinued, the soil being allowed to dry out as much as possible. Cultivation. — The cultivation is generally performed with hand implements. The field should be hoed from one to five times, depend- ing upon the weed growth, character of the soil, and the number of irrigations. If the soil is of a heavy texture, it should be hoed after Fig. 7.- -The cultivation of onions should be such that no weeds will be allowed to grow. each irrigation, but on the more open soils the time of cultivation is governed largely by the weed growth. Hoeing should always be shallow for if the earth is disturbed too deeply near the plants, there is liability of cutting off many of the roots. After the bulbs are one-half to two-third grown it is a good plan in hoeing the field, to place a small amount of earth over them for protection against heat. This is especially important during mid-summer in the interior sections of the state. Breaking Down Tops. — When the plants are forming large necks or seed stalks instead of bulbs, the breaking over of the tops a few 11 inches from the ground is recommended. There are several methods for doing this, the choice depending largely upon the size of the field. In large areas this may be done by dragging a board or rolling a barrel over the tops, but in a small garden they may be broken by stepping on them. If the crop is growing normally this practice is unnecessary. Harvesting.— It is very important that the harvesting be done at the proper time ; if it is deferred too long the crop will be a partial, if not a total loss, for if the onions reach maturity and are not pulled Fig. 8. over of the tops is one ind for harvesting. ition that the crop is ready from the ground they will send out new rootlets in a very short time, especially if there is an abundance of soil moisture. This second growth is very difficult to check and it will make the onions unfit for anything but immediate use. There is also danger from sunburn by leaving the mature bulbs exposed during hot weather. The customary period at which to harvest, is when the majority of the tops of the onions have begun to turn greenish yellow. Unfor- tunately all of the onions will not mature at the same time, but it is better to harvest some before they are wholly mature than to allow a portion of the crop to remain in the field a considerable time after it has ripened. 12 The crop may be harvested by hand or by the use of some imple- ment. Where a small variety is grown the former method is generally practiced, but when growing a large variety, such as the Italian Red, it will often be found more advantageous to dig the crop by means of a hoe or certain implements which are made especially for this work. After the onions have been taken out of the ground they are thrown in windrows or piles in the field, where they remain until the tops are completely dry. The length of time they are kept in these piles is determined by the degree of maturity, and the climatic conditions. : (Courtesy of A. Levy and J. Zentner Co.) Fig. 9. — Curing and sacking a 200-acre field of onions. In the interior of the state, during the warmer months, from three to seven days will be sufficient, but in the colder sections a longer time is often required. After curing sufficiently, the tops are cut off from one-half to one inch from the bulbs. In doing this it will be found most advantageous to use a knife or shears and care should be taken not to bruise the bulbs. After topping, the onions are placed immediate in sacks or crates and hauled to their shipping point or to a shed. Onions which are maturing during the spring and summer are usually shipped as soon 13 as possible, but the crop which is dug in the fall may either be dis- posed of immediately or placed in storage. The California onion crop is marketed either in sacks holding 100 to 105 pounds, or in crates containing 50 pounds net. STORAGE A large percentage of the onion crop is sold directly from the field, especially when it matures during the spring and summer. If it is desired to grow a crop for storage, the date of planting should (Courtesy of A. Levy and J. Zentnei- Co.) Fig. 10. — Method of storing onions during the winter. be late enough in the spring so that the onions will not mature before October, for it has been found very unsatisfactory to store onions during the warmer months unless they are kept under constant refrig- eration. If the crop is harvested in October it will be possible to keep it in satisfactory condition up to March or even later, provided the proper methods are used. Onions which are kept in storage must be protected from the rains and from freezing, The customary method for holding the crop is by placing it in weather-proof sheds or barns. Such structures must be well ventilated and the onions may either be placed in bins or stored in sacks. 14 During the warm winter days the house should be kept closed and the doors generally opened at night, providing the weather is not too severe. Even though the storage facilities are adequate, there will often be more or less trouble and it is sometimes necessary to sort over the onions one or more times, throwing away all those which have started to rot or sprout, for a few rotted onions will, under moist conditions ruin much of the contents of the sack. It is only after much experience that one will be able to hold a crop in storage successfully for several months, and as there is con- siderable shrinkage in weight, and the expense for sorting is large, one should not enter into this phase of the work, at least in a large way, without having had some previous experience. (Courtesy of A. Levy and J. Zentner Co.) Fig. 11. — In the delta, after sacking, the onions are hauled to the river banks and loaded on barges. ONIONS AS A TRUCK CROP In the production of onions in the market gardens throughout the state, the area varies from one to five acres. Onions are, however, produced on a more extensive scale and some of the onion farms comprise as many as 200 acres or more. Onions which are produced on the truck farms are usually grown 15 from seed planted directly in the field and the rows are spaced far enough apart so that the cultivation may be done with horse-drawn implements. The seeding generally starts in January and continues until March or April. The onion seed is planted by means of drills and the rows are spaced from fifteen inches to two feet apart. It is estimated that from three to four pounds of seed will be required per acre. After the plants are from two to four inches in height the plantings should be thinned, leaving the space between every two plants from three to four inches. At the time of thinning, the field is generally hand-hoed. The water is supplied either by running in furrows between the rows of plants, or by sub-irrigation. The crop is harvested and stored in the same manner as when grown in the market garden. Fig. 12.— Italian Red. 16 VARIETIES California Red. — A medium-sized, flat, very early maturing variety, red in color, of fair keeping quality and grown chiefly for its early maturation. Produced principally in Sacramento and delta sections. Stockton Red. — Very similar to the California Red in habits of growth and appearance. Grown principally in the delta. Italian Red. — A very large, red, medium early maturing variety, pear or bottle shape and very sweet. It stands shipment fairly well. It is grown principally at Sacramento. Fig. 13. — Yellow Globe Danvers. Yellow Globe Danvers. — Early maturing, yellow in color, medium size and good in shipping quality. A very desirable variety to grow on light soils. It is grown in all onion-producing sections of the state. Yellow Flat Danvers. — Grown under similar conditions as the Yellow Globe Danvers, but differs in shape. South Port White Globe. — A very popular white variety; keeps well, and is grown extensively over the state. Bermuda. — Very popular, early maturing variety, especially suited for sandy soil and grown principally in southern California. Australian Brown. — A very popular and widely grown variety, especially adapted for fall maturing and storage in the winter; best 17 suited for the delta sections, as the growth is better on peat or muck soils than on those of a drier nature. It is late in maturing and a general favorite on the market. Back Skin. — Grown commonly in the delta and resembles the Australian Brown in manner of growth, appearance and keeping qualities. Prize Taker. — A large yellow onion, good keeper and recommended for a fall crop. ONION SEED PRODUCTION California has long been recognized as the leading onion-seed producing state. The principal sections in which this crop is culti- vated are located in Santa Clara, San Benito, Santa Barbara, San Joaquin, and Sacramento counties. During the season of 1917 there were 5000 acres devoted to onion seed production in this state ; the average planting during the past ten years has been 3500 acres. The increase represented by these figures is due to the heavy demand for seed, owing chiefly to the European conditions; from present indications there will be a much larger acreage planted during the coming year. YIELD, COST OF PRODUCTION, AND PRICES RECEIVED The yield of seed varies from 300 to 500 pounds per acre ; it is influenced largely by the climatic conditions, and the variety. Occa- sionally yields of 800 to 1000 pounds per acre are secured, but during an unfavorable season, in which dry hot winds are prevalent at the time the seeds are forming, the crop may be a partial, or a total failure. When the bulbs are produced by the growers, the cost of growing one acre of onion seed will vary from $75 to $90, exclusive of rent or the cost of fertilization. The prices paid for onion seed vary from 30 to 50 cents per pound, depending on the variety and the care of the grower. CULTURAL REQUIREMENTS Onion seed may be grown successfully on a large variety of soils, provided the latter are rich. Rich loams, and adobe in good physical condition are commonly used for this purpose ; the peat soils are not as desirable, as the seed is liable to be rather light and shriveled. The moisture requirements are similar to those needed for grow- ing onions for the market. 18 GROWING THE BULBS Onion seed is produced by transplanting the matured onion, and the seed for this crop should be sown from February to April, inclusive. The manner of production is similar to that used for growing onions for the market. The onions may be harvested during September and October, and cured and sacked preparatory to transplanting. A bulb one-half to three-quarters grown is more commonly used for seed production than a large onion. PLANTING THE BULBS The bulbs may be planted in the field from October to February, inclusive, setting them six inches to one foot apart in rows from three to four feet apart, the exact distance depending largely upon the variety and the size of the bulbs. The bulbs may be set in the field before the rains commence; where a large area is to be grown, it is better to use this method than to plant too late in the winter. Where more than one variety is used, they should be separated from each other and should never be planted so that the prevailing winds will blow the pollen from one variety to another. It is a good plan to grow some tall, quick-growing crop such as corn or sunflowers between every two varieties and they should be separated by at least one hundred yards. In the future care of the crop no weeds should be allowed to grow. A good supply of moisture should continually be present in the soil for if the growth of the plants is checked the yield will be lessened. When the seed stalks are about one foot tall, the earth should be drawn toward the plants. It is often desirable to irrigate the plants once or twice during the season and this may be done by sub-irrigating or running the water in furrows between the plants, being careful not to allow it to run over them. With normal rainfall it will not be necessary to irrigate until the seed stalks start to grow. If a second irrigation is necessary, this should be done before the seed has developed in the heads. HARVESTING The time to harvest is largely dependent on the local conditions, but it generally falls during July and August. Occasionally onion seed is matured during the latter part of June. It is very important 19 that the crop be harvested at the proper time, for if the plants are over ripe, much of the seed will shatter, but should it be harvested before it is fully matured the seed will be of inferior quality. The proper time for harvesting is when the seed cases are opening and it is often necessary to go over the field two or three times before the entire crop is gathered. The stalk should be cut from one to two inches from the head, placed on canvas, thoroughly dried, spread in a layer two or three feet deep, and separated from the seed heads. This is done by rolling with a two-horse roller or threshing machine. The Fig. 14. — Onion seed nearing maturity. seed is then run through a blower or cleaner which will remove much of the chaff and some of the undeveloped light seed. It may be dipped in water, allowing the seed to remain submerged for a few minutes. The light seed and chaff is then scraped off from the surface. The good seed will be found at the bottom, and should be taken out and dried on canvas immediately and sacked. The seed is not always dipped in water and unless the grower has had previous experience, this should be done very cautiously, for if the seeds are submerged too long they will sprout and lose their value. 20 SELECTION OF THE BULBS In order to produce onion seed of good quality, it is very important that a careful selection of the bulbs be made, using only those which conform to the type. It is, therefore, imperative that the grower know exactly the kind of onion which he wishes to develop and the most careful growers make two selections, one to be used for the production of the commercial seed and the other for the seed to be used in the future for growing the bulbs. The following table illustrates the necessity of planting onion seed which is not over two years old ; seed one year old is preferable : Vitality of Onion Seedi California-grown seeds No. samples viable Seed stated to be less than one year old 400 88 J 8 Seed stated to be between one and two yearst old 220 77.46 Seed stated to be between two and three years old 2,023 57.43 Seed stated to be between three and four years old 1 10.00 There is an excellent opportunity for the production of this crop in California for a grower who is careful to produce seed of high quality, but the demands of the market are becoming so exacting that there is very little encouragement for the careless seed grower. CROP TROUBLES Under normal conditions the onion crop in California is compara- tively free from disease and insect pests. The following are the most common troubles which occasionally cause considerable damage : Damping Off. — This disease is found in the seed bed and may attack the young seedlings at the time they are coming through the surface and until they have grown their second pair of true leaves. The plants wither and fall over as if they had been cut off at the surface of the ground. The trouble is first noticed by the appearance of a few scattered affected plants, but under favorable conditions the disease will spread very rapidly through the bed. This condition is caused by several fungi which live in the soil, and is most common during wet weather, especially if the growth of the plants is slow. After the disease has become established, it is very difficult to control ; the following recommendations are suggested for avoiding i Biennial Ker>ort, Conn. Agr. Exp. Sta., 1909-1910, pt. 12, p. 114. 21 this condition : Good drainage, irrigate seldom but thoroughly and in the morning only, isolate the diseased plants by digging a furrow four inches deep or pouring formalin around the affected areas. The following spray will also be found advantageous : Bluestone 3 lbs. Lump lime 4 lbs. Water 50 gals. Mildew. — This disease is troublesome during warm, moist weather and is most commonly found in districts having considerable fog. It attacks the stalks and leaves, causing large dead areas upon which may be seen the dark purplish-colored mildew. This is especially troublesome in growing onion seed as the seed stalks fall over, and development of the seed stop. To quote Professor R. E. Smith regard- ing the disease : This disease has not been successfully controlled in California, but in the eastern states has yielded fairly well to* spraying with bordeaux mixture to which a resin sticker has been added. This spraying must be done at frequent intervals, commencing before the mildew appears. The development of resistant strains by seed selection is promising.2 Failure to Produce Bulbs. — Occasionally a large part of the crop will develop seed stalks and large neck onions or scullions, instead of marketable bulbs. This condition may be caused from planting in the wrong season, sudden check in the growth of the plants, or poor seed. The remedy lies in" planting only seed of good quality, and irrigating frequently enough so that the growth may be steady and uniform. When early spring onions are desired, the plants should not be set in the field before November; when the seeding is done directly in the field, they should be planted not earlier than December. Breaking over of the tops or cutting off the seed stalks when the crop is maturing will correct this trouble considerably. Onion Thrips. — To quote Essig regarding this pest : The constant chafing of the thrips upon the leaves produces countless numbers of small white or silvery spots which are very noticeable. The growth of the plant is often stunted by the attacks. This species of thrips is generally distributed throughout the entire state. It is often very troublesome to onion growers in the warm interior valleys and in the Imperial Valley. 2 Calif. Agr. Exp. Sta., Bui. 218, p. 1133. 22 Control. — Like mites, thrips are very difficult to control, because of their large numbers, exceedingly small size and the tender plants which they infest. Many sprays will readily kill them because of their small size, but the nature of the host plant does not always permit such treatment. Tobacco decoctions and lime-sulphur or oil emulsions give very good results. The following formula is recommended by J. R. Watson: Commercial lime-sulphur (33° Baume) 5% gals. "Black Leaf 40" (tobacco decoction) 14 fluid ozs. Water 200 gals. The addition of one part of "Black Leaf 40" to two thousand parts of an oil emulsion or a miscible oil spray will also give good results. To spray a spreader composed of 4 gallons of flour paste (1 pound of flour to each gallon of water dissolved to make a paste) to every 100 gallons will greatly aid and give much better results than if used alone. 3 Suppl. to Mo. Bui. Cal. State Comm. Hort., 1915, p. 56. STATION PUBLICATIONS AVAILABLE FOR FREE DISTRIBUTION 1897. 1902. 1903. 1904. 1914. 1915. 1916. 1917. REPORTS Resistant Vines, their Selection, Adaptation, and Grafting. Appendix to Viticultural Report for 1896. Report of the Agricultural Experiment Station for 1898-1901. Report of the Agricultural Experiment Station for 1901-03. Twenty-second Report of the Agricultural Experiment Station for 1903-04. Report of the College of Agriculture and the Agricultural Experiment Station. Report of the College of Agriculture and the Agricultural Experiment Station. Report of the College of Agriculture and the Agricultural Experiment Station. Report of the College of Agriculture and the Agricultural Experiment Station. No. 230. 241. 242. 246. 248. 250. 251. 252. 253. 255. 257. 261. 262. 263. 264. 265. 266. 267. 268. 270. No. 113. 114. 115. 121. 124. 126. 127. 128. 129. 131. 133. 135. 136. 137. 138. 139. 140. 142. 143. 144. 147. 148. 150. 151. 152. 153. 154. 155. 156. 157. 158. BULLETINS No. Enological Investigations. 271. Vine Pruning in California, Part I. 272. Humus in California Soils. 273. Vine Pruning in California, Part II. The Economic Value of Pacific Coast 274. Kelps. The Loquat. 275. Utilization of the Nitrogen and Organic Matter in Septic and Imhoff Tank 276. Sludges. 277. Deterioration of Lumber. 278. Irrigation and Soil Conditions in the 279. Sierra Nevada Foothills, California. 280. The Citricola Scale. New Dosage Tables. 282. Melaxuma of the Walnut, "Juglans regia." 283. Citrus Diseases of Florida and Cuba 284. Compared with Those> of California. 285. Size Grades for Ripe Olives. 286. The Calibration of the Leakage Meter. 288, Cottony Rot of Lemons in California. A Spotting of Citrus Fruits Due to the 290. Action of Oil Liberated from the Rind. Experiments with Stocks for Citrus. 291. Growing and Grafting Olive Seedlings. A Comparison of Annual Cropping, Bi- ennial Cropping, and Green Manures on the Yield of Wheat. CIRCULARS No. Correspondence Courses in Agriculture. 160. Increasing the Duty of Water. 161. Grafting Vinifera Vineyards. 162. Some Things the Prospective Settler Should Know. 164. Alfalfa Silage for Fattening Steers. 165. Spraying for the Grape Leaf Hopper. House Fumigation. 166. Insecticide Formulas. 167. The Control of Citrus Insects. 168. Spraying for Control of Walnut Aphis. County Farm Adviser. 169. Official Tests of Dairy Cows. 170. Melilotus Indica. Wood Decay in Orchard Trees. 172. The Silo in California Agriculture. 174. The Generation of Hydrocyanic Acid 175. Gas in Fumigation by Portable Ma- chines. 176. The Practical Application of Improved Methods of Fermentation in Califor- 177. nia Wineries during 1913 and 1914. 181. Practical and Inexpensive Poultry Ap- pliances. 182. Control of Grasshoppers in Imperial Valley. 183. Oidium or Powderv Mildew of the Vine. 184. Tomato Growing in California. 185. "Lungworms." Round Worms in Poultry. 186. Feeding and Management of Hogs. 187. Some Observations on the Bulk Hand- 188. ling of Grain in California. 190. Announcement of the California State 191. Dairy Cow Competition, 1916-18. 192. Irrigation Practice in Growing Small 193. Fruits in California. 196. Bovine Tuberculosis. 197. How to Operate an Incubator. Control of the Pear Scab. 198. Home and Farm Canning. Feeding Dairy Calves in California. Commercial Fertilizers. Preliminary Report on Kearney Vine- yard Experimental Drain. The Common Honey Bee as an Agent in Prune Pollination. The Cultivation of Belladonna in Cali- fornia. The Pomegranate. Sudan Grass. Grain Sorghums. Irrigation of Rice in California. Irrigation of Alfalfa in the Sacramento Valley. Trials with California Silage Crops for Dairy Cows. The Olive Insects of California. Irrigation of Alfalfa in Imperial Valley. The Milch Goat in California. Commercial Fertilizers. Potash from Tule and the Fertilizer Value of Certain Marsh Plants. The June Drop of Washington Navel Oranges. The Common Honey Bee as an Agent in Prune Pollination. (2nd report.) Lettuce Growing in California. Potatoes in California. White Diarrhoea and Coccidiosis of Chicks. Small Fruit Culture in California. Fundamentals of Sugar Beets under California Conditions. The County Farm Bureau. Feeding Stuffs of Minor Importance. Spraying for the Control of Wild Morn- ing-Glory within the Fog Belt. The 1918 Grain Crop. Fertilizing California Soils for the 1918 Crop. Wheat Culture. Farm Drainage Methods. Progress Report on the Marketing and Distribution of Milk. Hog Cholera Prevention and the Serum Treatment. Grain Sorghums. Control of the California Ground Squirrel. Extending the Area of Irrigated Wheat in California for 1918. Infectious Abortion in Cows. A Flock of Sheep on the Farm. Beekeeping for the Fruit-Grower »:id Small Rancher, or Amateur. Poultry on the Farm. Utilizing the Sorghums. Lambing Sheds. Agriculture Clubs in California. Pruning the Seedless Grapes. Cotton in the San Joaquin Valley. A Study of Farm Labor in California. Dairy Calves for Veal. Suggestions for Increasing Egg Pro- duction in a Time of High-Feed Prices. Syrup from Sweet Sorghum.