UNIVERSITY OF CALIFORNIA COLLEGE OF AGRICULTURE AGRICULTURAL EXPERIMENT STATION BERKELEY, CALIFORNIA THE ASPARAGUS INDUSTRY IN CALIFORNIA H. A. JONES AND W. W. ROBBINS BULLETIN 446 January, 1928 UNIVERSITY OF CALIFORNIA PRINTING OFFICE BERKELEY, CALIFORNIA 1928 THE ASPARAGUS INDUSTRY IN CALIFORNIA H. A. JONESi and W. W. EOBBINS2 INTRODUCTION Asparagus has always ranked high as a market garden and truck crop. New Jersey early took the lead, and for many years held first place in the production of green asparagus. California became the center of the asparagus industry after the ravages in 1896 of the asparagus rust in the East. The first attempt to can asparagus in this country was made by William H. Hudson, at Hunter's Point, Long Island, in 1864. The product proved to be popular and the industry grew in New York and New Jersey. It was not until 1890 that the packing of asparagus in California became extensive. There has been a marked increase in the acreage devoted to asparagus in recent years. Although there is no accurate record available of the acreage in the different states, it is probably safe to say that the total acreage in the United States has more than doubled since 1918. There has been a steady growth of the asparagus industry in California since its inception. The centers of production have shifted somewhat until, today, the three main districts are the Delta, the Imperial Valley, and the San Fernando Valley. This bulletin contains material which will be of use to the farmer who is growing asparagus for the first time ; it also gives the results of recent experiments and observations conducted by the California Agricultural Experiment Station; and it summarizes data published by other investigators which may be of application to California conditions. Botanical Relationships and Geographical Distribution. — Asparagus is a member of the lily family (Liliaceae). A number of the repre- sentatives of the lily family are cultivated as vegetables, the principal ones being onions and asparagus. The only species of asparagus which has been cultivated extensively in the United States as a food plant is Asparagus officinalis. A striking characteristic of the genus Asparagus is the slender green branches, which usually occur in clusters, and from the axils 1 Associate Professor of Truck Crops and Plant Breeder in the Experiment Station. 2 Associate Professor of Botany and Botanist in the Experiment Station. 4 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION of which the flowers arise. These slender branches are known as cladodes or cladophylls. The true leaves are either scale-like struc- tures as in A. officinalis, or spine-like as in many of the tropical, ornamental species. All species of Asparagus may be propagated by division of the rootstocks. Of the common species of Asparagus, A. officinalis is the only one which grows erect and produces edible shoots. Other common species are climbing or drooping in their habit. Moreover, in A. officinalis, the plants are dioecious; that is, male (staminate) and female (pisti- late) flowers are borne on different individual plants. In the common climbing or drooping species the flowers are perfect, that is, possess both stamens and pistils. The genus Asparagus is distributed from Siberia to South Africa. The native home of Asparagus officinalis is somewhat more limited, ranging from Great Britain through Europe to Central Asia. It is commonly mentioned as a plant of the seashores and riverbanks. Asparagus has escaped from cultivation wherever it has been grown. Although not a native of America, it early escaped from gardens and flourished in the wild state. THE SEED, SEED GERMINATION, AND DEVELOPMENT OF THE PLANT THE FIRST SEASON External Characters of the Seed. — In any lot of asparagus seeds, it will be observed that there are two distinct shapes, as shown in figure 1. If two seeds develop in a single cavity of the berry, the surfaces which touch become flattened because of pressure. However, if but a single seed develops in a seed cavity, it becomes equally rounded on all sides. There is no reason to believe that either one of these types of seed is superior to the other. There is considerable variation in the weight of asparagus seed among different varieties. Seed obtained from different sources may vary considerably in size owing to different methods of screening. The seed of the Martha Washington strain is smaller, and that of the Mary Washington is somewhat larger, than the seed of most other varieties. There is found a pronounced difference in the glossiness of the seed coats of various lots of seed. Some are shiny black, whereas others are a dull color. It is believed that dullness is due at least in part to the age of the seed. In different lots of seed, there is considerable variation in the amount of fruit wall (pericarp) which is attached to Bul. 446] THE ASPARAGUS INDUSTRY IN CALIFORNIA the seed. This appears as a thin, white papery coating. Incomplete threshing and washing are responsible for the presence of these membranes. **SI & a : r4 Fig. 1. — Two shapes of asparagus seeds (top view). Left, rounded seed from loeule which bcre but this one seed ; right, seed flattened on one side, from locule which produced two seeds. (From Bul. 381.) ..seed coat Fig. 2. — Diagrams of asparagus seeds showing position of the embryo. A, section through the seed showing the embryo in longitudinal section. B, section through the seed showing the embryo in transverse section. (From Bul. 381.) 6 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION Internal Structure. — The asparagus seed has three essential parts (fig. 2) : (1) the seed coat; (2) the embryo plant or germ; (3) the endosperm or reserve food. Figure 3 shows a section of the mature seed coat. In the develop- ment of the seed coat there has been a progressive desiccation and shrinkage of the cells, with a consequent decrease in the thickness of this coat, The outer wall of the single, epidermal layer of cells becomes very thick, and the lumina become almost completely filled \ endosperm Fig. 3. — Section of a portion of an asparagus seed, showing the seed coat and the large cells of the endosperm, with thick walls of hemicellulose ("reserve cellulose"), and cell cavities filled with oil globules and protein granules. (Treated 18 hours with 2 per cent sodium hydroxide solution in order to swell the cells of the seed coat.) Illustration from Bui. 381. with a dark, brown granular material. Beneath this epidermal layer are the very much compressed and dried remains of integumentary cells. Beneath these is a suberized membrane, separable into a broad membrane and a narrow one closely compressed. These represent respectively the "cuticles" of the inner and outer integuments. This double membrane plays a very important part in the absorption processes carried on by the seed, preventing, either totally or in part, the entrance of certain salts and other substances, although it does BUL. 446] THE ASPARAGUS INDUSTRY IN CALIFORNIA 7 not inhibit the movement of water through it. The bulk of the seed is composed of endosperm cells, which contain food reserves. The embryo is a very small, slender body, simple in structure and somewhat curved at one end (fig. 2). At one end of the embryo is the root tip. A short distance behind the root tip is a shallow depression, at the base of which is the growing point, The remainder of the embryo, and by far the largest part, is an absorptive organ. This organ, the cotyledon, remains in contact with the endosperm during the early stages of germination, absorbs food from the endosperm and delivers it to the growing regions. The embryo is completely surrounded by the endosperm. Most endosperm cells have thick pitted walls of hemicellulose, and lumina well filled with fat globules and protein granules. The hard, flinty endosperm constitutes a reserve food supply. There are two chief kinds of food stored in the endosperm of asparagus. These are hemicellulose and fat. Protein is relatively less abundant as a storage product. Hemicellulose is a carbohydrate somewhat resembling starch and ordinary cellulose in its chemical composition. Hemicellulose is stored in the walls of the endosperm cells ; fat occurs as droplets in the cell cavities. The hardness of the endosperm of the asparagus seed is due to hemicellulose in its walls. Seed Storage. — There are many conditions which affect the vitality of seeds. In a ripe seed, the essential part, the living embryo, or young plant is in a relatively inactive state. The conditions under which seeds are stored should be such as to keep it inactive. The temperature should be kept fairly low and uniform, and the atmos- pheric humidity low. If seeds are not stored in a dry place, the moisture present may be sufficient, provided there is the proper tem- perature and oxygen supply, to start germination. If germination processes are started, it follows that the respiration rate increases, with a consequent loss of dry weight and a decrease in the amount of stored food and therefore of stored energy in the seeds. Seeds stored in bulk under such conditions may "heat." This may be due in part to heat liberated by the respiration of the seeds themselves and in part to the heat of respiration of fungi and bacteria growing on the seeds. The heat thus developed may become so intense as actually to kill the embryos. Under the best storage conditions, asparagus seed should remain viable for a period of from five to seven years. It is always best to make a germination test on asparagus seed before planting to determine the percentage of viable seeds, so that the seeding rate can be accurately ascertained. 8 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION Conditions Necessary for Germination. — The requirements for the germination of asparagus seed, and in fact of all seeds, are water, oxygen, and a proper temperature. In certain experiments, asparagus seeds have been kept in water for three months without showing evidence of germination, and this prolonged soaking in water at ordinary temperatures does no apparent injury to the seeds, for when they are removed from the water and placed under conditions suitable for germination, sprouts appear within a few days and the percentage of germination is normal. Asparagus seeds submerged in water are under a condition of low oxygen supply, but they may be made to germinate within four or five days if the water is aerated by bubbling air through it. The above experiments point to the conclusion that asparagus seed will endure long soaking in water at ordinary tem- peratures. However, germination of the seed will not result unless there is a plentiful supply of oxygen, such as occurs in a soil in good physical condition. The optimum temperature for the germination of asparagus seed is between 77° and 86° F. At 68° F, germination is very slow. Germination of asparagus seed will be slow if sown in a soil the temperature of which is 68° F or below. The absorption of water by the seed at temperatures below 77° F is very slow. Rate of Germination. — The rate of germination of asparagus seed depends upon water and oxygen supply and upon the soil tempera- ture. With all conditions near the optimum, the root breaks through the seed coat within 6 to 8 days after planting ; within 10 or 12 days the first shoot appears. The time required for the shoot to reach the surface of the soil depends not only upon the supply of water and oxygen, and upon the temperature, but also upon the depth of plant- ing and texture of the soil. The sooner the shoot reaches the light, becomes green, and begins to manufacture its own food, the greater are its chances of survival. If, however, the developing seedling must struggle through an excessive depth of soil or one in poor physical condition, it may exhaust its food supply and succumb before reaching the surface. Hastening the Germination of Asparagus Seed. — Borthwick (3) has shown that it is possible to hasten the germination of asparagus seed by soaking it in water. Both laboratory and field data show that soaked seeds germinate more quickly than unsoaked seeds, even though planted in cold soil. For practical purposes, a period of 3 to 5 days' soaking at a temperature of 86° to 95° F is recommended. The Germination Processes and Stages in the Development of the S<< working in California, found that dusting with sulfur gave satisfactory control. When rust appears early, one application of 25 to 30 pounds to the acre about three weeks after the cutting season, and another about a month later, should usually be sufficient. On newly planted beds or when cutting stops early in the season, more than two applications may be necessary. However, it is impossible to give specific directions that will cover all conditions. Finely divided sulfur gives the best results. The plants should be thoroughly covered with dust. If the acreage is small, the sulfur can be applied with a hand duster; in large fields, however, a power duster should be used that will cover several rows at a time. Other Methods of Control. — Burning the stalks of infested fields in the fall will kill many of the spores. This does not add greatly to the preventive methods, however, as the "needles" which have become infected fall off after severe frosts and usually before the tops are cut and burned. Volunteer plants about the edges of the fields, in fence rows, and on the levees and ditch banks, should be grubbed out so that they will not harbor the disease. The fields should be planted so that they will secure good aeration ; the rows should run in the direction of the prevailing winds. It is usually inadvisable to plant windbreaks about the asparagus fields. In regions, such as the Delta, where rust usually does not appear on the older beds until fall, the best and cheapest method of rust control is to secure good field aeration. Violet Root Rot (Rhizoctonia crocorum var. asparagi (Pers.) D.C.). — In parts of Europe the losses from violet root rot of asparagus have been widespread and sometimes severe. The disease has been reported in the United States, but has occasioned no losses worthy of note. In the asparagus bed, violet root rot is usually first noticed attack- ing only a few plants, but every year, unless the disease is checked, new surrounding plants are infected and die. On newly infected 96 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION plants, the mycelium shows itself on the roots as a violet-colored mass of filaments. In badly infected plants, the soft tissue of the roots is largely destroyed, and they have the appearance of hollow, withered tubes, sometimes covered with characteristic small violet or dark tufts. INSECTS AND OTHER PESTS The asparagus plant, both in Europe and America, is host to a number of very destructive insect pests. The Common Asparagus Beetle (Crioceris asparagi L.). — The common asparagus beetle is found in almost all of the asparagus growing regions of Europe and America. In the United States the damage caused by it appears to be less in the southern than in the northern states. So far as known, it has not been reported as occur- ring in the Imperial Valley of California. Description. — The adult beetle is a slender and graceful insect, slightly less than one-fourth inch long. It is blue-black in color with red thorax and dark blue wing covers, marked with lemon yellow and with reddish borders. The markings of the wing covers are quite variable, the pale color sometimes forming submarginal spots, while in other specimens it becomes so diffused as to form the principal color of the wing covers. Like a squirrel, it commonly hides on the opposite side of the branch when approached. The egg is dark brown and oval, is nearly one-sixteenth of an inch long, and is laid on end. The eggs are deposited upon the stems or foliage, usually two to seven or more in a row. The mature larva is about one-third of an inch long, soft and fleshy, much wrinkled, and of a dark gray or olive color, with shining black head and legs. The mature larva drops to the ground from the asparagus plant, and just beneath the soil surface forms a small, rounded, thin, earth-covered cocoon (fig. 40), within which it changes to the pupa, The latter is yellowish in color. Life History. — The insect winters over in the adult stage, hiber- nating in rubbish and other protected places. In the latitude of the District of Columbia (Chittenden), the beetles usually appear in April, but as a rule in most districts they appear about the same time as the asparagus in the spring. The beetles soon start to lay eggs. These hatch in from three to eight days, depending on the tempera- ture. The larvae soon become full grown in from ten to fourteen days, and then pupate in the soil. The adult beetle emerges in about a week. The insect may pass through its entire life cycle in as short a time as three weeks, though it may take a month or more. In its BUL. 446] T HE ASPARAGUS INDUSTRY IN CALIFORNIA 97 Fig. 40. — Cocoons of asparagus beetle. Observe the adult beetle. 98 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION northern range, usually two generations are produced in a season ; farther south, as many as four broods may be produced. In California (Essig (9) ) there are many overlapping generations each year. Nature of Injury. — Both the larval and adult stages of the aspara- gus beetle feed upon the marketable spears as well as upon the foliage and stems of the mature stalks. During the cutting season the adults do the greatest amount of damage by depositing their eggs upon and eating holes in the spears, making them unsightly and lowering their market value. Control. — Asparagus beetles are held in check to a certain extent by natural enemies. Several species of ladybird beetles feed upon the eggs, while numerous soldier-bugs and small dragon flies prey upon the larvae. According to Johnston (13) at times the beetle is kept under control by a parasitic wasp-like fly, Tetrastichus asparagi Cwfd. The parasite deposits its eggs on those of the asparagus beetle ; the beetle egg hatches, the larva grows to maturity, enters the soil and forms a pupal cell but does not pupate because the pupa is entirely consumed by the parasite. The parasites pupate and later come forth as adults from the cell which the beetle larva has constructed. In the Concord, Massachusetts, district Chittenden (6) has observed that large numbers of hibernating beetles are killed during the winter, especially when extremely low temperatures follow a period of warm weather. During extremely high temperatures, exposed larvae, as well as eggs, are destroyed. This injury by extremes of temperature probably holds this pest in check in the far northern and the extreme southern districts and probably accounts for its not being found in the Imperial Valley. Chickens and ducks feed upon both the adults and the larvae and do not injure the plants; however, their use is limited to small areas. Air-slacked lime dusted on the plants, when wet with dew, will kill the larvae but not the adults. In certain districts where the attacks are especially severe, the spears are cut white; as soon as the tips appear, they are harvested before the beetle has an opportunity to do any great amount of damage. When cutting white asparagus, trap hills or trap rows of asparagus can be used to good advantage. The beetles are forced to congregate and feed on the rows or hills that are not being cut. These should be thoroughly dusted or sprayed with an arsenical every week or ten days. It will also be necessary to grub out the volunteer host plants about the edges of the fields and ditches if good results are to be expected. BUL. 446] T HE ASPARAGUS INDUSTRY IN CALIFORNIA 99 Where green asparagus is being cut, trap crops are not so effective, as the beetles can feed and lay their eggs upon the young spears before they are harvested. The spears are cut, however, before the eggs hatch. On the young beds, and after the cutting season on the older ones, an excellent method of control is to spray with lead arsenate, using 4 pounds of lead arsenate paste and 4 pounds of resin fishoil soap to 50 gallons of water. A dust comprised of 1 part of powdered arsenate and 8 to 10 parts of air-slaked lime applied while the plants are wet with dew will also give excellent control. Young larvae are effectively killed with 5 per cent nicodust. A number of asparagus growers in the Delta report complete extermination of hibernating beetles in fields that have been flooded during the winter. To obtain the best control, community action is necessary. The Twelve-spotted Asparagus Beetle (Crioceris duodecimpunc- tata L.) has not been reported as occurring in the western United States and is probably confined to the eastern half. Asparagus Miner (Agromyza simplex Loew.). — The asparagus miner has a wide distribution and has been reported as occurring in many sections of the country, including Florida, Texas, Washington, and California. At times it becomes very abundant in the north. Description. — According to Fink (14) the adult is a glistening metallic black fly about one-sixth of an inch in length and with a wing expanse of about one-fifth of an inch. The males are somewhat smaller than the females, and have a more or less triangular shaped abdomen. One of the striking features in the adult is a picture of a face on the thorax. When first laid, the egg is glistening white in color. It measures 0.5 millimeters in length and 0.12 millimeters in width. The egg is elongate-oval, slightly widened at one end, and more or less pointed at the other. The egg shell is at first viscid and transparent so that the embryo is clearly visible through the shell. When first hatched, the larva is pure white, but when fully grown is cream-Avhite. When mature it is 4-5 millimeters long, about five times longer than wide, of nearly uniform diameter throughout a greater portion of its length, and narrowing slightly toward either end. When first formed, the pupa is light brown ; later it becomes dark brown. It is flat and curved when viewed from the side. A pair of hooks is borne at each end of the pupa, by means of which it attaches itself firmly beneath the epidermis of the asparagus stalk. Life History. — Fink (10) reports that in the vicinity of Ithaca, New York, the adults probably make their appearance about the middle of 100 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION May, the males appearing several days before the females. The female starts to deposit eggs within a week after she emerges. Eggs are usually laid at the base of the stalk, at or near the surface of the ground or below the surface, if the soil is loose. The eggs are deposited individually just below the epidermis. It is rather difficult to find the eggs unless the female is found ovipositing. If a stalk on which the oviposition has been observed is pulled out and examined carefully with a hand lens, tiny punctures leading to raised areas will be^seen. If the epidermis is carefully peeled from these raised areas, the egg is found adhering either to the peeled epidermis or to the tissues of the stalk below. It is more difficult for the female to penetrate old stalks, and in case eggs are deposited on these part of the egg may remain protruding from the epidermis. The entire life cycle, except the adult stage, is passed in conceal- ment beneath the epidermis of the asparagus stalk. The eggs hatch in twelve to eighteen days. When hatched the larvae begin to mine their way up the stalk for a foot or more above the surface of the soil and then work downward again, thus producing zigzag mines. Usually a number of larvae are found on the same stalk. When nearly full-grown, the larvae direct their mines down- ward. During the summer they may pupate anywhere along the stalk; later they pupate at depths of one inch or more below the soil surface. The pupae are found in the mines where larvae have stopped feeding. During the summer, the insects remain in the pupal stage two to three weeks. The fall brood, however, winters over in the pupal stage. In California, according to Essig, (9) the flies appear early in the spring ; there are at least two generations a year. Nature of Injury. — The injury to the asparagus stalks is done by the larvae which mine at the base of the stalk under the epidermis. Chittenden (6) reports finding pupae under the outer skin of the roots, also. Cases have been reported in which entire beds have been destroyed by the ravages of this insect. The adult does not lay eggs on the young spears (Fink) during the cutting season, but by prefer- ence oviposits on the stalks in the new beds and in the nursery. Control. — Methods of control used at the present time are not entirely satisfactroy. Fink (10) recommends the addition of syrup as an attractant to an arsenical spray, which is used to kill the adults. He also recommends pulling and destroying the infested stalks in late fall or early spring. These stalks generally turn yellow and in severe cases die before the non-infested. Btjl. 446] THE ASPARAGUS INDUSTRY IN CALIFORNIA 101 The Asparagus Fly (Platyparea pocciloptera Schrank). — So far no mention has been made of this pest in the United States. The Garden Centipede (Scutigerella immacidata Newport). — The garden centipede is found widely distributed throughout the world. It is an economic pest in many of the important truck crop regions of California, Oregon, and Utah. So far as known, it has not been reported as a serious asparagus pest except in the Delta region of California. Fig. 41. — Asparagus or garden centipede (adult). X 10. Fig. 42. — Eggs of the garden centipede (much enlarged). Description. — The adult (fig. 41) is small and unusually white in color, though its body is often tinged by colored food material in the digestive tract. When feeding on young asparagus shoots, however, they are almost transparent white. According to Wymore, (28) the adults vary in length from 2.7 to 6.7 millimeters; they have one pair of many-jointed antennae, an eye-like body just back of each antenna, four pairs of mouth appendages; twelve pairs of well-developed legs, the first pair four-jointed, all the rest five-jointed. Life History. — According to Wymore, (28) "When first laid the eggs are a pearly white and as the time for hatching approaches they become a dirty white color (fig. 42). They are % to % millimeter in diameter and are covered with tiny ridges giving the appearance of a net work. "When just hatched the larvae are hairy, vary from 0.9 to 1.1 millimeters in length, and have six pairs of legs." The first molt occurs three to five days after hatching. 102 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION Fig. 43. — Injury to asparagus due to garden centipede. BuL. 446] TPIE ASPARAGUS INDUSTRY IN CALIFORNIA 103 The life history has not been worked out in detail. Wymore was able to find adult specimens in the soil about the asparagus crowns at almost any time of the year. During the first part of June, the young greatly outnumber the adults, but by the middle of August, 90 per cent of the individuals taken in the field were mature. The centipedes feed beneath the surface of the soil, eating small holes in the spears and making them unfit for canning. Control. — Wymore (28) recommends flooding for a period of two weeks where the ground is kept covered to a depth of a foot or more and all asparagus tops, stubble, and other debris are entirely sub- merged. He states that where the soil, but not the stubble, was covered with four or five inches of water, very good results were obtained by stirring up the muddy soil with a potato hook, thus disturbing the centipedes and allowing water to reach them more quickly. If this was not done, it seemed impossible to drown the pests, although the soil was kept covered for three or four weeks with several inches of water. Evidently in this case, the insects found lodgment in and about the stems and received sufficient oxygen which was conveyed down the stems that projected above the water surface. Flooding as a means of control cannot be used in many of the asparagus districts outside of the Delta, except where a large supply of water is available. To date, satisfactory control methods by use of repellants and soil- fumigants have not been developed. Other Pests. — Other insects reported by Essig as feeding on asparagus in California are : the Harlequin Cabbage Bug {Murgentia histrionica Hahn.), Orange Tortrix (Tortrix citrana Fernald), and the Yellow Bear Caterpillar (Diacrisea virginica Fab.). Wymore observed that the tops of several acres of asparagus in the Delta in the late autumn of 1922 turned white from the injury of pentotomids (chiefly Chlorochrou sayi Stal. and Thyanta eitstator Fab.). The bugs were found in large clusters on the stems about 18 inches from the tips of the branches, where they were girdled by the many punctures from the mouth parts. The authors have observed red spider and thrips in considerable abundance on the asparagus plants, especially during late summer. Thrips injury has been found to be very serious in nursery beds in the San Fernando Valley. In early spring Aphis sp. are often found on the spears and on the young seedlings in the nursery. Gophers feed upon both the fleshy roots and stalks and do considerable damage if not trapped. 104 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION LITERATURE CITED i Bisson, C. S., H. A. Jones, and W. W. Bobbins. 1926. Factors influencing the quality of fresh asparagus after it is har- vested. California Agr. Exp. Sta. Bui. 410:1-28. 2 Bitting, K. G. 1917. Deterioration in asparagus. Nat. Canners Assoc. Bui. 11:1-18. s Borthwick, H. A. 1925. Factors influencing the rate of germination of the seed of Asparagus officinalis. California Agr. Exp. Sta. Tech. Paper 18:1-17. * Bottner, J. 1921. Praktischer Lehrbuch des Spargelbaues 122: p. 74, figs. 1-74. Trovitsch, Frankfurt. 5 Brooks, W. P., and F. W. Morse. 1919. A fertilizer experiment with asparagus. Massachusetts Agr. Exp. Sta, Bui. 194:231-257. 6 Chittenden, F. H. 1917. The asparagus beetles and their control. U. S. Dept, Agr. 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Spargelbau und Konservegemiise nach Braunschweiger Methode. (ed. 2.) 63 pp. Paul Parey, Berlin, ic Morse, Fred W. 1913. Some effects of fertilizers on the growth and composition of asparagus roots. Massachusetts Agr. Exp. Sta. Ann. Rept. 25:156. BUL. 446] T HE ASPARAGUS INDUSTRY IN CALIFORNIA 105 17 Myers, C. E. 1916. Experiments with asparagus. Pennsylvania State College Ann. Rept., pp. 557-578. is Norton, J. B. 1919. Washington asparagus: information and suggestions for growers of new pedigreed rust-resistant strains. U. S. Dept. Agr. Off. Cotton, Truck and Forage Diseases Circ. 7:1-8. is Rousseaux, E., and C. Brioux. x 1906. Recherches sur la culture de l'Asperge dans l'Auxerrois. (Memoirs Societe d 'encouragement pour l'industrie nationale) 112 pp. Siege de la Societe, Paris. 20 Rudolfs, W. 1921. Experiments with common rock salt. I. Effect on asparagus. Soil Sci. 12:449-456. 2i Smith, R. E. 1905. Asparagus and asparagus rust in California. California Agr. Exp. Sta. Bui. 165:1-99. 22 Smith, R. E. 1904. Report on asparagus rust investigations. California Agr. Exp. Sta. Circ. 9:1-20. 23 Tiedjens, Victor A. 1924. Some physiological aspects of Asparagus officinalis. Proc. Amer. Soc. Hort. Sci. 21:129-140. 24 Walker, E. 1905. Asparagus and salt. Arkansas Agr. Exp. Sta. Bui. 86:31-36. 25 Warren, G. F., and Jennie A. Voorhees. 1907. JSTew Jersey Agr. Exp. Sta. Ann. Rept. 27:189-223. 26 Working, E. B. 1922. Physical and chemical factors in the growth of asparagus. Carnegie Inst. Wash. Year Book 21:63-64. 27 Working, E. B. 1924. Physical and chemical factors in the growth of asparagus. Arizona Agr. Exp. Sta. Tech. Bui. 5:85-124. 28 Wymore, F. H. 1924. The garden centipede, Scutigerella immaculata (Newport), a pest of economic importance in the West. Jour. Econ. Ent. 17:520- 526. STATION PUBLICATIONS AVAILABLE FOR FREE DISTRIBUTION No. 253. Irrigation and Soil Conditions in the Sierra Nevada Foothills, California. 262. Citrus Diseases of Florida and Cuba Compared with those of California. 263. Size Grades for Ripe Olives. 268. Growing and Grafting Olive Seedlings. 273. Preliminary Report on Kearney Vine- yard Experimental Drain, Fresno County, California. 276. The Pomegranate. 277. Sudan Grass. 278. Grain Sorghums. 279. Irrigation of Rice in California. 283. The Olive Insects of California. 294. Bean Culture in California. 804. A Study of the Effects of Freezes on Citrus in California. 310. Plum Pollination. 312. Mariout Barley. 813. Pruning Young Deciduous Fruit Trees. 819. Caprifigs and Capriication. 324. Storage of Perishable Fruit at Freez ing Temperatures. 825. Rice Irrigation Measurements and Experiments in Sacramento Valley, 1914-1919. 328. Prune Growing in California. 331. Phylloxera-Resistant Stocks. 835. Cocoanut Meal as a Feed for Dairy Cows and Other Livestock. 839. The Relative Cost of Making Logs from Small and Large Timber. 840. Control of the Pocket Gopher in California. 343. Cheese Pests and Their Control. 344. Cold Storage as an Aid to the Mar- keting of Plums. 346. Almond Pollination. 347. The Control of Red Spiders in Decid nous Orchards. 848. Pruning Young Olive Trees. 349. A Study of Sidedraft and Tractor Hitches. 850. Agriculture in Cut-over Redwood Lands. 853. Bovine Infectious Abortion. 354. Results of Rice Experiments in 1922. 857. A Self-mixing Dusting Machine for Applying Dry Insecticides and Fungicides. 858. Black Measles, Water -Berries, and Related Vine Troubles. 361. Preliminary Yield Tables for Second Growth Redwood. 362. Dust and the Tractor Engine. 863. The Pruning of Citrus Trees in Cali- fornia. 864. Fungicidal Dusts for the Control of Bunt. 365. Avocado Culture in California. 866. Turkish Tobacco Culture, Curing and Marketing. 367. Methods of Harvesting and Irrigation in Relation of Mouldy Walnuts. 368. Bacterial Decomposition of Olives dur- ing Pickling. 369. Comparison of Woods for Butter Boxes. 370. Browning of Yellow Newtown Apples. 371. The Relative Cost of Yarding Small and Large Timber. 373. Pear Pollination. 374. A Survey of Orchard Practices in the Citrus Industry of Southern Cali- fornia. 375. Results of Rice Experiments at Cor- tena, 1923. 376. Sun-Drying and Dehydration of Wal nuts. 377. The Cold Storage of Pears. 379. Walnut Culture in California. BULLETINS No. 380. 382. 385. 386. 387. 389. 390. 391. 392. 393. 395. 396. 397. 399. 400. 401. 402. 404. 405. 406. 407. 408. 409. 410. 411. 412. 414. 415. 416. 417. 418. 419. 420. 421. 422. 423. 424. 425. 426. 427. 428. 429. Growth of Eucalyptus in California Plantations. Pumping for Drainage in the San Joaquin Valley, California. Pollination of the Sweet Cherry. Pruning Bearing Deciduous Fruit Trees. Fig Smut. The Principles and Practice of Sun- drying Fruit. Berseem or Egyptian Clover. Harvesting and Packing Grapes in California. Machines for Coating Seed Wheat with Copper Carbonate Dust. Fruit Juice Concentrates. Crop Sequences at Davis. Cereal Hay Production in California. Feeding Trials with Cereal Hay. Bark Diseases of Citrus Trees. The Mat Bean (Phaseolus aconitifo lius). Manufacture of Roquefort Type Cheese from Goat's Milk. Orchard Heating in California. The Blackberry Mite, the Cause of Redberry Disease of the Himalaya Blackberry, and its Control. The Utilization of Surplus Plums. Cost of Work Horses on California Farms. The Codling Moth in Walnuts. The Dehydration of Prunes. Citrus Culture in Central California. Stationary Spray Plants in California. Yield, Stand and Volume Tables for White Fir in the California Pine Region. Alternaria Rot of Lemons. The Digestibility of Certain Fruit By- products as Determined for Rumi- nants. Factors Affecting the Quality of Fresh Asparagus after it is Harvested. Paradichlorobenzeno as a Soil Fumi- gant. A Study of the Relative Values of Cer- tain Root Crops and Salmon Oil as Sources of Vitamin A for Poultry. Planting and Thinning Distances for Deciduous Fruit Trees. The Tractor on California Farms. Culture of the Oriental Persimmon in California. Poultry Feeding: Principles and Practice. A Study of Various Rations for Finishing Range Calves as Baby Beeves. Economic Aspects of the Cantaloupe Industry. Rice and Rice By-products as Feeds for Fattening Swine. Beef Cattle Feeding Trials, 1921-24. Cost of Producing Almonds in Cali- fornia ; a Progress Report. Apricots (Series on California Crops and Prices) . The Relation of Rate of Maturity to Egg Production. Apple Growing in California. Apple Pollination Studies in Cali- fornia. The Value of Orange Pulp for Milk Production. The Relation of Maturity of Cali- fornia Plums to Shipping and Dessert Quality. Economic Status of the Grape Industry. CIRCULARS No. No. 87. Alfalfa. 259. 117. The Selection and Cost of a Small 261. Pumping Plant. 262. 127. House Fumigation. 263. 129. The Control of Citrus Insects. 264. 136. Melilotus indica as a Green-Manure Crop for California. 265. 144. Oidium or Powdery Mildew of the 266. Vine. 157. Control of the Pear Scab. 267. 164. Small Fruit Culture in California. 166. The County Farm Bureau. 269. 170. Fertilizing California Soils for the 270. 1918 Crop. 272. 173. The Construction of the Wood-Hoop Silo. 273. 178. The Packing of Apples in California. 276. 179. Factors of Importance in Producing 277. Milk of Low Bacterial Count. 202. County Organizations for Rural Fire 278. Control. 203. Peat as a Manure Substitute. 279. 209. The Function of the Farm Bureau. 212. Salvaging Rain-Damaged Prunes. 281. 215. Feeding Dairy Cows in California. 217. Methods for Marketing Vegetables in California. 282. 230. Testing Milk, Cream, and Skim Milk for Butterfat. 283. 231. The Home Vineyard. 284. 232. Harvesting and Handling California 285. Cherries for Eastern Shipment. 286. 234. Winter Injury to Young Walnut Trees 287. during 1921-22. 288. 238. The Apricot in California. 289. 239. Harvesting and Handling Apricots 290. and Plums for Eastern Shipment. 291. 240. Harvesting and Handling Pears for Eastern Shipment. 292. 241. Harvesting and Handling Peaches for 293. Eastern Shipment. 294. 243. Marmalade Juice and Jelly Juice from 295. Citrus Fruits. 244. Central Wire Bracing for Fruit Trees. 296. 245. Vine Pruning Systems. 248. Some Common Errors in Vine Prun- 298. kig and Their Remedies. 249. Replacing Missing Vines. 300. 250. Measurement of Irrigation Water on 301. the Farm. 302. 252. Supports for Vines. 303. 253. Vineyard Plans. 254. The Use of Artificial Light to Increase 304. Winter Egg Production. 305. 255. Leguminous Plants as Organic Fertil- 306. izer in California Agriculture. 256. The Control of Wild Morning Glory. 307. 257. The Small-Seeded Horse Bean. 308. 258. Thinning Deciduous Fruits. 309. Pear By-products. Sewing Grain Sacks. Cabbage Growing in California. Tomato Production in California. Preliminary Essentials to Bovine Tuberculosis Control. Plant Disease and Pest Control. Analyzing the Citrus Orchard by Means of Simple Tree Records. The Tendency of Tractors to Rise in Front; Causes and Remedies. An Orchard Brush Burner. A Farm Septic Tank. California Farm Tenancy and Methods of Leasing. Saving the Gophered Citrus Tree. Home Canning. Head, Cane, and Cordon Pruning of Vines. Olive Pickling in Mediterranean Coun- tries. The Preparation and Refining of Olive Oil in Southern Europe. The Results of a Survey to Determine the Cost of Producing Beef in Cali- fornia. Prevention of Insect Attack on Stored Grain. Fertilizing Citrus Trees in California. The Almond in California. Sweet Potato Production in California. Milk Houses for California Dairies. Potato Production in California. Phylloxera Resistant Vineyards. Oak Fungus in Orchard Trees. The Tangier Pea. Blackhead and Other Causes of Loss of Turkeys in California. Alkali Soils. The Basis of Grape Standardization. Propagation of Deciduous Fruits. The Growing and Handling of Head Lettuce in California. Control of the California Ground Squirrel. The Possibilities and Limitations of Cooperative Marketing. Coccidiosis of Chickens. Buckeye Poisoning of the Honey Bee. The Sugar Beet in California. A Promising Remedy for Black Measles of the Vine. Drainage on the Farm. Liming the Soil. A General Purpose Soil Auger and its Use on the Farm. American Foulbrood and its Control. Cantaloupe Production in California. Fruit Tree and Orchard Judging. The publications listed above may be had by addressing College of Agriculture, University of California, Berkeley, California. 12m-3,'28