CALIFORNIA AGRICULTURAL EXTENSION SERVICE CIRCULAR 76 JULY, 1933 Production of the Globe Artichoke in California A. A. TAVERNETTI 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 Acknowledgments 2 Production areas in California 4 Characteristics of the globe artichoke 4 Climatic and soil requirements 7 Varieties 7 Propagation 8 Planting 9 Fertilizer requirements 10 Irrigation 10 Cultivation 11 Cutting the stems 12 Yields 13 Seasonal market demands 14 Harvesting and packing 15 California standards for globe artichokes 18 Federal standards for globe artichokes 18 Federal-state inspection 19 Marketing 20 Value of leaves and stems for feed 20 Insects: Artichoke aphid 22 Bean aphid 22 Black grass bug 22 Artichoke plume moth 22 Diseases: Botrytis sp 23 Black tip 23 Yellows 24 ACKNOWLEDGMENTS The author wishes to express his appreciation for the assistance given by Mr. II. A. Hunt, Agricultural Commissioner of Monterey County, in preparing that portion of the manuscript dealing with insects and diseases. Dr. II. A. Jones, of the Division of Truck Crops, has also assisted in the preparation of this manuscript. PRODUCTION OF THE GLOBE ARTICHOKE IN CALIFORNIA A. A. TAVEENETTIi Although the globe artichoke has been a popular vegetable in southern Europe for over 2,000 years, it has only recently become important in America. The French people of Louisiana and the Italians of California are mainly responsible for its introduction and popularization in the United States. Although classed as a distinct species, the globe artichoke is a very close relative of cardoon, and was probably developed from it. TABLE 1 Acreage of Artichokes in California, 1924-25 to 1932-33' County Marin Monterey San Luis Obispo San Mateo Santa Cruz Total. 1924-25 300 3,600 400 3,250 3,000 10,550 1925-26 300 4,010 600 3,570 3,280 11,760 1926-27 300 4,010 600 2,210 2,820 9,940 1927-28 250 3,400 500 1,800 2,000 7,950 County 1928-29 1929-30 1930-31 1931-32 1932-33 Marin Monterey 250 4,000 500 2,550 1,600 250 3,800 500 2,200 1,400 8,150 250 3,500 450 1,900 1,400 250 2,500 480 1,800 1,300 300 3,600 520 1,800 1,300 Total 8,900 7,500 6,330 7,520 * Data from California Cooperative Crop Reporting Service, courtesy of Carl M. Schiller. Many students of the origin of cultivated plants believe the Mediter- ranean region to be the native home of the globe artichoke, its ancestor probably having come originally from North Africa. At the present time the cardoon and the globe artichoke are both grown commercially in California ; the former is grown for its edible leaf stalks, while the latter is grown for its edible flower buds and associated parts. Another plant, the Jerusalem artichoke, a tuberous-rooted sunflower, is some- times grown for its edible roots. Although it belongs to the same family as the globe artichoke it is not a close relative, and the two should not be confused. Specialist in Agricultural Extension. [3] California Agricultural Extension Service [ c ir- ? 6 PRODUCTION AREAS IN CALIFORNIA Commercial plantings of the globe artichoke in California are limited to the five coast counties extending from Marin, on the north, to San Luis Obispo, on the south. The maximum acreage was reached during the 1925-26 season ; the lowest record since that time was during the 1931-32 season (table 1). Fig. 1. — Artichoke plantings along the coast in Santa Cruz County. The industry in California was introduced by Italians in the Half Moon Bay district of San Mateo County, and at the present time this crop is grown almost exclusively by people of Italian origin. It is esti- mated that in 1906 there were 1,500 acres of artichokes in this area, but in recent years Monterey County has taken the lead in production with San Mateo second and Santa Cruz third (fig. 1) . CHARACTERISTICS OF THE GLOBE ARTICHOKE The artichoke plant is a herbaceous perennial ; that is, the tops die down each year, but are renewed again from the crown below the soil. Each summer when the seeds mature, the leaves and stems aboveground die, but the roots and crown remain alive and in a more or less dormant condition until the advent of favorable growing conditions. The marketable portion of the plant, the so-called "bud," is really the immature flower head made up of flower buds and numerous bracts or scales, closely laid one upon the other. The buds range from 1 to 4 inches in diameter. The edible portion consists of the tender base of the bracts, the young flowers, and the receptacle, the latter being the fleshy base upon which the flowers are borne. 1933] Production of Globe Artichoke 5 The plant attains a height of from 3 to 4 feet or more ; the diameter is about 6 feet but varies somewhat with the age of the plant. Growth consists mainly of a number of seasonal shoots in various stages of maturity, growing up from a permanent crown. The number varies from a single shoot in young plants to 12 or more in plants that are four or five years old. Each shoot forms at first a cluster of large basal or rosette leaves from the center of which later the stem elongates. It is upon this elongated stem that the edible buds are produced. The buds are borne terminally on the main stem and its lateral branches. Under natural conditions, a new growth begins with the advent of the rainy season, the edible buds forming the following spring. By insti- tuting certain cultural practices, however, it has been possible to force the plant to grow out of its normal season and produce over a much longer season, and at a time when the market demand is greatest. If the buds are not removed, they develop into purple-centered thistlelike flower heads 6 to 8 inches in diameter. Viable seeds are produced in abundance. According to Scott, 2 there are from 12 to 20 dormant buds in the axils of the rosette leaves of the transplanted shoot at the end of the first growing season. When conditions again become favorable, these axillary buds at the base of the stem start growth. In most cases only 6 or 8 of these buds will produce shoots, each one of which forms a rosette of leaves and later produces a flower stem ; these again die at the end of the second growing season. With the advent of favorable conditions at the beginning of the third growing season 6 or 8 buds at the base of each stem again produce suckers. This process is continued during the entire life of the plant. Each new shoot then is a lateral branch arising from a bud at the base of the flowering stem of the season just preceding. Under cultivation the number of shoots is reduced by the practice of cutting the old flower stems several inches below the surface. As the new shoot grows it develops a mass of small fibrous roots. These grow rapidly and are concentrated in the upper foot of soil. They function as organs of absorption as long as the shoot upon which they are borne is growing actively. Toward the end of the season they increase markedly in size and become fleshy, after which their function seems to be that of storage rather than absorption. The main storage product in the fleshy roots is inulin. 2 Scott, G. W. Morphological and chemical studies of the globe artichoke. Proc. Amer. Soc. Hort. Sci. 27:356-359. 1930. California Agricultural Extension Service [Cir. 76 Fig. 2. — Artichoke plants badly injured by freezing. Note the droop- ing of the large buds. PU" f!lM if- • 1 \ v . • ; ' : , ■' ■■■■! ^wSm Fig. 3. — Freezing injury causes the skin to blister and turn white, which detracts much from the market value. 1933 ] Production of Globe Artichoke CLIMATIC AND SOIL REQUIREMENTS Although the globe artichoke prefers a cool climate, it is readily damaged by cold (fig. 2). At temperatures slightly below freezing, the outer skin of the bud scales is injured, giving a blistered whitish appear- ance which greatly lowers its marketability (fig. 3). Still lower tem- peratures completely kill the buds, causing them to turn black in a few hours. Following periods of such temperatures, harvest is delayed from 2 to 6 weeks, or until new buds have developed. When temperatures become so low that all growth aboveground is killed, harvesting may be delayed from 6 to 8 weeks. Commercial plantings should be limited to areas where winter pro- duction is possible. Those areas should be selected that are as near frost free as possible during the winter, and cool and foggy during the sum- mer. The district most nearly approaching these conditions in California is the fog-belt region along the central coast. A climate that is hot and dry causes the buds to open, thereby destroying the tenderness of the edible portion. The globe artichoke will grow on a wide range of soil conditions, but it produces best on a deep fertile well-drained soil. Since temperature and humidity conditions limit the areas suitable for commercial pro- duction, it is sometimes necessary to sacrifice the ideal in soil require- ments to obtain proper climatic conditions. Many plantings are made on the gently sloping hills overlooking the ocean. The soils on these hill- sides are usually not very productive and require considerable fer- tilization. The artichoke plant is deep rooted and should not be planted on soils that do not afford adequate root area. Steep slopes or extreme unevenness of topography should be avoided. A plentiful supply of irrigation water is essential. VARIETIES Varieties of the globe artichoke are not clearly defined. This is the case because no systematic breeding or selection work has been done. There is considerable variation, however, in the shape of the bud, which ranges from long and somewhat pointed in the Italian varieties (fig. 4), to almost round or flattened at the ends in the French varieties. The ex- tremely flattened type is not desirable because it is a poor yielder and is difficult to pack. Soil and climatic conditions influence somewhat the quality of the bud, causing variations in shape, color, and compactness. California Agricultural Extension Service [ Ci R- 76 PROPAGATION In the early history of the industry, plantings were considered rather permanent and were not renewed except at long intervals. While the plant itself will continue to grow indefinitely, it has been found more profitable to renew plantings every three or four years because produc- tion and quality fall off materially after the third year. Fig. 4. — Upper : Two types of artichokes commonly grown in California. Left, cone-shaped bud of the Italian type which is preferred. Right, flattened bud of the French type. Lower: A longitudinal section of the types shown in the upper figure. Propagation from seed is not practicable for the reason that the globe artichoke does not grow true to variety from seed. Most of the plants grown from seed produce buds of little or no commercial value. The best method of obtaining desirable plants is to select shoots from plants of desirable characteristics and of known productivity. Shoots occur in abundance at the base of old plants. They are usually selected 1933] Production of Globe Artichoke 9 and removed any time from November to March when 12 to 18 inches high, taking care to save all of the roots possible. If not set immediately, the shoots should be stored in a cool, moist place to prevent drying. Previous to planting, the tops are usually cut back as shown in figure 5. Fig. 5, -Young offshoot pruned and ready for planting. Some growers, in place of using suckers in making new plantings, set the old rootstocks in order to obtain, immediately, a large number of sprouts. It is questionable if this is any improvement, because of the greater loss of plants and the longer time required for the old rootstocks to develop shoots. PLANTING Before planting, the field should be leveled for irrigation and well pulverized, and made smooth to allow for marking off. Care should be exercised in laying out the field to allow for roadways and to facilitate both cultivation and irrigation. On slopes of extreme grade, contour planting is desirable in order to prevent excessive erosion when the soil is irrigated. The rows are usually 8 feet apart and the plants spaced 6 feet in the row. This distance can be varied slightly according to soil conditions. Planting is usually done by hand. Each plant is set 6 to 8 inches deep 10 California Agricultural Extension Service [Cm. 76 and firmed in the soil. If the soil is dry, the plants should be irrigated immediately. The plant first produces a single stem but soon others form at the base. FERTILIZER REQUIREMENTS Fertilizer requirements of artichokes consist mainly in keeping the soil supplied with an adequate amount of active organic matter. On the poorer soils, frequent applications of manure are probably the most economical means of keeping the soil in a productive state. In California, the artichoke is planted mainly on those types of soil that respond readily to applications of nitrogenous fertilizers. If nitrogen is applied in the inorganic form, the application should be made before the buds begin to form and preceding irrigation. Heavy applications have been found to be more effective and economical than those recommended for most other crops. Some growers apply 10 to 12 tons of manure to the acre immediately after cutting the stalks in the summer, then 400 pounds of either nitrate of soda or sulfate of ammonia just before harvesting begins. Although manure is used in quantity by only a few of the growers, the use of in- organic nitrogen in such forms as ammonium sulfate is quite general. Maintaining soil fertility by means of covercrops is not practicable because of the extensive foliage growth of the artichoke plant. In a newly planted field it is sometimes possible to interplant with a crop like peas ; this gives an additional income and increases the fertility of the soil. The leaves and stems should be returned to the soil whenever feas- ible ; this increases the organic matter of the soil and returns certain fertilizer constituents. IRRIGATION The globe artichoke requires frequent irrigation during the growing period. A deficiency of moisture, particularly during the time the buds are forming, results in a loose bud of inferior quality. Irrigation water can be applied by various methods, depending upon the contour of the land. As the plants are in rows, furrow irrigation is a common method. The use of surface pipe and temporary ditches where needed is more economical than the use of permanent open ditches. While the plants are small a common practice is to construct a tem- porary levee midway between the rows ; the water is allowed to enter at the high end and made to spread by constructing temporary cross levees with a shovel (fig. 6). In the older beds the time of the first irrigation depends upon when the buds are wanted for harvest. For early winter production, it should 1933] Production of Globe Artichoke 11 be made immediately following the cutting of the tops. This is usually in the months of May and June. In any event, it should be given by the fore part of August in order to allow the plants to make their maximum Fig. 6. — A common system of irrigation is to combine the f urroAv and check methods. Temporary levees are constructed between the plants. size by winter. Growth starts immediately after the first irrigation and should continue uninterrupted until harvest is over. From three to five irrigations during a growing season are usually required. The amount of water applied at a single irrigation should be sufficient to wet the soil to the full rooting depth of the plant. The globe artichoke will not tolerate standing water. On heavy soils, it is often desirable to construct a drainage ditch at the lower end of the furrows to drain off excess water. CULTIVATION The chief purpose of cultivation should be to control weeds and to help incorporate fertilizer and the cut tops into the soil. Plowing away from the plants and making a back-furrow midway between the rows keeps weeds under control and also constructs a temporary levee to serve during irrigation. After each irrigation, the soil between the rows should be disked or chiseled to kill weeds and smooth the surface. As the plants mature care should be exercised not to destroy the surface roots by too deep cultivation. Check planting has the advantage of permitting cultivation both ways between the plants. This is usually possible only while the plants are 12 California Agricultural Extension Service [Cm. 76 small, as plants are generally set closer together in the row than between rows. In fields of mature plants, the rows become almost a solid mass of growth. CUTTING THE STEMS After all the buds of a stem have been harvested, it is a good practice to remove them in order to allow new stems to form. As a rule, this should be done several times during the harvesting season. Fig. 7. — A type of cutter used in removing tops after the last harvest in the spring. After the last harvest in spring, the leaves and stems are cut off several inches below the level of the ground. It is desirable first to plow away from the plants, leaving a furrow on each side of the row. Then an implement, with a single slanting blade, is pulled down the row to cut off the stems (fig. 7) . The knife of the cutter should extend from one furrow to the other, with the knife several inches below the surface of the soil. Considerable power is necessary to pull the cutter. With certain types of tractors it is possible to mount the knife directly on the rear frame. Following the cutting, the leaves and stems may be allowed to dry, then placed in piles and burned ; or they may be disposed of by placing them in a dead-furrow or ditch previously made in the center of every other row (fig. 8) . By back-furrowing with a plow, the tops can be covered 1933] Production of Globe Artichoke 13 easily. About three months are required for complete decomposition of the tops after covering. In recent years machines have been perfected which cut off the stems and leaves, shred them, and return them to the soil immediately without interfering with tillage operations. Fig. 8. — To dispose of tops after cutting, ditches are made between every other row. The tops are then placed in the ditches and covered with soil to hasten decay. YIELDS Buds of good quality are usually produced the first year. Plantings made in February and March produce buds in September, and if old stems are removed will continue to produce throughout the first winter. Maximum production occurs the second and third years following plant- ing. The yield of buds varies with the period of harvest. Harvesting usually ceases in the spring because of a decrease in demand when other green vegetables become available, rather than from shortage of buds. 14 California Agricultural Extension Service [Cir. 76 From 1925 to 1930 the estimated average yield of globe artichokes, based on carlot shipments, was about 120 forty-pound boxes per acre. The actual yields are probably somewhat higher than this, because there is a quantity of artichokes shipped in mixed cars, which have not been considered in this estimate. SEASONAL MARKET DEMANDS The globe artichoke is primarily a winter vegetable and does not move readily into consumption except during that time of the year when there is relatively little competition from other vegetables. The main shipping season begins in September and ends in April of the following 1 * F JH 1 s i •%*»p*t : Fig. 9. — Artichoke buds of good type. A bud of good type has the bracts closely laid, and is free from blemishes. A soft and flexi- ble stem indicates that the flower parts have not become coarse or inedible. year. Small shipments, however, often by express, are made throughout the year to some markets. Large buds (fig. 9) are in greater demand than the small ones, espe- cially by people not of Italian origin. It is rarely possible to market many of the small sizes at a profit under normal conditions. The smaller sizes are used mainly by the French and Italians. In recent years the smaller sizes have been canned as artichoke hearts although the demand for this product has not developed sufficiently to absorb large quantities of these sizes. The pack in California has in- creased, however, from 15,000 cases during the 1924-25 season to 55,522 during the 1930-31 season. 1933 J Production of Globe Artichoke 15 HARVESTING AND PACKING Harvest begins with the maturing of the first buds in the fall and con- tinues until the following spring unless interrupted by frost. The peak of production comes in early spring. Pickings are made weekly except during periods of cold weather, which retards growth. In selecting the buds for harvest, their size, compactness, and age are taken into con- sideration. Beyond a certain age, regardless of size, the buds become loose, fibrous, and inedible. As a rule, several buds develop on a single flower stalk, but the most desirable one usually occurs on the tip of the main stem. Harvesting is done by cutting the stem 1 to 1% inches below the base of the bud, according to the size. The cutters go down each row remov- ing the buds and placing them in sacks carried about the waist. These are taken to the end of the row and then transported to the packing shed. While harvesting, it is a good practice to remove and discard buds too old for market. As harvesting is intermittent, packing on the ranch rather than at a central packing-house allows for a better utilization of labor. Usually the same laborers can be employed in harvesting and in packing. The buds are first graded by machine into five or six different sizes (fig. 10) . They are then selected for quality and packed in paper-lined boxes. A sufficient number of layers are used to give a good bulge to the pack when lidded. Two sizes of boxes are used for shipping (fig. 11). The large box is 9% by 11 by 20% inches; the small or half box is 4% by 11 by 20% inches. For local shipments artichokes are usually packed in lugs that are 8% by 14 by 22% inches. The size of the buds is designated by the number in a box. This varies from 48 to 200. The number in a full box may be 48, 60, 72, 84, 96, 110, 125, 150, or 200 (fig. 12). The most desirable sizes are 48 and 60 to the box. These command a premium in price over smaller sizes. In packing 48 to a box, four layers of 12 buds each are used. Each layer comprises two rows of 6 buds each. To the trade this is known as a 2 x 2 pack. When packing 60 to the box, four layers of 15 buds each are used. Each layer consists of three cross rows of 3 buds and three cross rows of 2 buds. This is termed a 2 x 3 pack. The 72 pack consists of four layers of 18 buds to each layer. The layers are made up of three rows lengthwise in the box of 6 buds to the row. This type of pack is termed a 3 x 3 pack. In the smaller sizes, the number of buds to the layer and the number of layers are increased. 16 California Agricultural Extension Service [Cm. 76 If shipped in carload lots, the boxes are placed in refrigerator cars, 504 large or 950 half boxes to the car. Twenty-five to 30 blocks of ice weighing about 300 pounds each are placed on top of the load. Fig. 10. — Upper : A mechanical grader in operation. The ropes of the carrier gradually separate, delivering buds to various bins. Lower: Another view of the mechanical grader. The buds of various sizes are dropped into compartments from which they are packed by hand for shipment. A considerable quantity of artichokes move from California in mixed cars with other vegetables such as lettuce, cauliflower, Brussels sprouts, carrots, finochio, endive, and peas. 1933] Production of Globe Artichoke 17 Fig. 11. — Upper: Packed boxes of artichokes ready for lidding. Lower: Two sizes of boxes used, showing proper bulge. Fig. 12. — Five different sizes of buds are packed. 18 California Agricultural Extension- Service t ClR - 76 CALIFORNIA STANDARDS FOR GLOBE ARTICHOKES The grading and packing of globe artichokes in California is regu- lated by the provisions as set forth in the California Fruit, Nut, and Vegetable Standardization Act of 1931. Sec. 28. Standard for globe artichokes. Globe artichokes shall be free from mold, decay, and insect injury or insect larvae; and free from serious damage, as denned in this section, caused by freezing or other means. Damage to any one artichoke from freezing shall not be considered serious unless the heart of the artichoke or that portion of the stem extending one and one-half inches or less, below the bottom of the artichoke, is discolored due to this cause. Damage from other means shall not be considered serious unless it causes a waste of ten per cent, by weight, of the edible portion of the individual artichoke. In order to allow for variation incident to proper grading and handling, not more than ten per cent, by count, of the globe artichokes in any one container or bulk lot may be below these requirements ; but not to exceed one-half of this toler- ance, or five per cent, shall be allowed for any one cause. In addition to the other requirements specified in this section, globe artichokes, when packed, shall be virtually uniform in size which shall mean a variation in size, between the artichokes in any one container, of not more than three-fourths of an inch in diameter when measured through the widest portion of the cross section. FEDERAL STANDARDS FOR GLOBE ARTICHOKES The U. S. Standard grades for globe artichokes formulated by the Bureau of Agricultural Economics, United States Department of Agri- culture, as of February 10, 1926, are as follows : U. S. No. 1 shall consist of artichokes which are properly trimmed, fairly well formed, fairly compact, not overdeveloped; and which are free from damage caused by worms, snails, bruising, freezing, disease, insects, or other means. (See "Size.") In order to allow for variations incident to proper grading and handling, not more than 10 per cent, by count, of any lot may be below the requirements of this grade but no part of this tolerance shall be allowed for decay. U. S. No. 2 shall consist of artichokes which are not badly spread or overdeveloped ; and which are free from serious damage caused by worms, bruising, freezing, insects or other means. (See "Size.") In order to allow for variations incident to proper grading and handling, not more than 10 per cent, by count, of any lot may be below the requirements of this grade but no part of this tolerance shall be allowed for decay. Unclassified shall consist of artichokes which are not graded in conformity with the foregoing grades. Size Artichokes in any package shall not vary more than % of an inch in diameter. The size of the artichokes in any package shall be plainly stamped or otherwise marked on the package in terms of numerical count or minimum size. 1933 J Production of Globe Artichoke 19 In order to allow for variations incident to proper sizing not more than 5 per cent, by count, of the artichokes in any package may be below the specified minimum size, or may vary from the %-inch range in diameter permitted in any package. Definitions of Terms As used in these grades: "Properly trimmed" means that the artichoke has a clean-cut short stem attached. "Fairly well formed." Artichokes are either of the short, chunky, rounded type with blunt end, or of the slightly long and pointed type. Artichokes are not fairly well formed if excessively long and pointed. "Fairly compact" means that the artichoke shall be reasonably firm and not more than slightly spreading. "Overdeveloped" means that the artichoke is of a brownish color; that the scales are tough, leathery and stringy; that the flower in the center of the bud has turned dark pink or purple and become fuzzy. "Damage" means any injury from the causes mentioned which materially affects the appearance or edible quality. "Serious damage" means any injury from the causes mentioned which seriously affects the appearance or edible quality. "Minimum size" means the largest transverse diameter of the smallest artichokes permitted in the package taken at right angles to a line running from the stem to the opposite end. FEDERAL-STATE INSPECTION The following brief synopsis of the history, function, and scope of the Federal-State inspection service is taken from Special Publication 32 of the California State Department of Agriculture : In July, 1920, there was established in California a commercial shipping-point inspection service carried on by the Bureau of Standardization of the State Depart- ment of Agriculture. This service employs a corps of experienced, highly trained men who are authorized to inspect and certify to the exact quality and condition of the produce at the time of packing and shipping. The demand for this service has increased steadily, and its scope and importance has been greatly enlarged. . . . On July 1, 1922, this service was federalized, each inspector being deputized by the federal government, and certificates are now prima facie evidence in all courts of the United States. This inspection is available in all of the leading vegetable-producing sections of the state. The certificate shows the hour and date of inspection, inspection or shipping point, name and address of the shipper or consignee (when given), car initials and number, kind of car and its condition; if a refrigerator, the amount of ice in the bunkers; the quantity of the products inspected; description of load and container; condition of pack ; sizing, quality, and condition of the product at the time the car is loaded, although he may be at a considerable distance from the shipping point. These shipping-point certificates are valuable to the grower, as they protect his interests in the adjustment of claims or on a declining market. On the other hand, the buyer is assured that he will receive the quality of produce for which he has paid 20 California Agricultural Extension Service [ Cir - 76 before seeing it. Whenever requested, a telegram giving the substance of an inspec- tion will be sent "collect" to the buyer or any other interested party, so that the exact condition of a carload can be ascertained before the sale is even consummated. MARKETING The marketing of globe artichokes has been discussed in Bulletin 524.3 rpj ie distribution for the 1930-31 season is given as follows : 613 carloads, or 45 per cent, went to California markets ; 423 carloads, or 29 per cent, to New York City ; 120 carloads, or 8 per cent, to Chicago. The balance of 18 per cent was distributed to 117 cities in the United States and Canada. The trade channels for sales in cities east of the Mississippi are as follows : The principal channel for sales in cities east of the Mississippi is: producer- shipper-receiver-jobber-retailer or push-cart peddler-consumer. The producer grades and packs the artichokes and delivers them to the shipper's loading shed. The shipper makes up carloads from the deliveries of growers, chooses the markets to which the carloads are to be shipped, and handles the documents incidental to the transactions between himself and the grower, the carrier, and his agent in eastern markets. The receiver sells principally to jobbers or to those who perform a similar function, who, in turn, sell to various retail outlets. From the records of shipments and interviews with various members of the trade, it is estimated that between 70 and 75 per cent of the sales in cities east of the Mississippi move in this manner. On the New York market, the push-cart peddler plays a most important part in the distribution of artichokes. It has been estimated that nearly 50 per cent of the total receipts of artichokes at that market reach consumers through the push-cart peddlers. Since they deal principally with the consumers of southern European origin, the smaller-sized artichokes are sold almost exclusively in this way. The inability of many markets to consume a full carload of artichokes makes the shipment of this commodity with mixed cars of other vege- tables necessary. Growers of artichokes may well give more considera- tion to the growing of other vegetables which can be included in mixed- car shipments. VALUE OF LEAVES AND STEMS FOR FEED The leaves and stems of the globe artichoke have a high food value and can be used profitably for feeding livestock. The fresh leaves are not particularly palatable, but if no other feed is available, sheep and cattle will eat them, with apparently good results. After the harvesting season cattle or sheep can be turned into the fields to browse. After they have eaten the leaves, the stems can be cut off by machine. 3 Stokdyk, E. A. Marketing globe artichokes. California Agr. Exp. Sta. Bui. 524:1-68. 1932. 1933] Production op Globe Artichoke 21 Fig. 13. — Upper: Chopping artichoke tops for ensilage. Lower: Filling the trench with ensilage. The trench provides economical storage facilities. 22 California Agricultural Extension Service t ClR - 76 A more satisfactory method is to ensile the leaves and stems at the time of cutting. The cured ensilage is very palatable and relished by all livestock. It resembles corn ensilage without the grain. In the preparation of the ensilage the leaves and stems should be cut immediately at the close of the harvest season to prevent the stems from drying or becoming woody. Shredding can be done with an ordinary corn ensilage cutter and the material prepared and stored in the same manner as with corn ensilage. Yields vary from 2 to 4 tons per acre. The cost of hauling, cutting, and curing is about the same as for corn. Since sufficient silos to hold all of the ensilage from a large acreage of globe artichokes are not always available, trench silos made in the soil at low cost can be used satisfactorily (fig. 13). Trenches are usually made 8 feet wide at the bottom, 12 feet wide at the top, 6 to 8 feet deep, and as long as desired. After filling, the silos should be covered with oiled paper or straw and several inches of dirt. In emptying, the silo can be uncovered at one end and a truck or wagon backed into the trench for loading. INSECTS Artichoke Aphid. — The artichoke aphid (Myzus hraggi Gill.) is a yellowish-green plant louse with dark markings which feeds on the undersides of the leaves of the artichoke plant. It causes serious injury to the plants by sucking out the sap, but may be controlled with a 5 per cent nicotine dust. A spray made of 1 pint Black Leaf 40, 4 to 5 pounds of whale oil or fish-oil soap, and 100 gallons of water is also effective if thoroughly applied to the undersides of the leaves. Bean Aphid. — Another aphid (Aphis rumicis Linn.), a dull-black species common on many plants including beans, dock, thistles, is a common pest on artichokes. It seldom becomes of importance in com- mercial artichoke plantings, but almost eliminates the possibility of backyard plantings in some localities. Control is the same as for the above species. Black Grass Bug. — The adult of the black grass bug (Irbisia solani Heid.) is a shiny black bug about % 6 inch long. It appears in great numbers in the spring after the native grasses have dried, eating almost any green vegetable that can be found. Artichokes near untilled areas are often seriously attacked. A 20 to 25 per cent calcium cyanide dust will control this pest. Artichoke Plume Moth. — The most common pest of artichokes is the artichoke plume moth (Platyptilia carduidactyla Riley). The moth is generally of a brown or buff color and has narrow wings with an expanse 1933] Production of Globe Artichoke 23 of % inch. The larvae are less than one inch long, and yellowish with a black head. They feed on the leaves and stems, but mainly on the developing buds, tunneling into them and at times causing severe losses (fig. 14). There are several broods during the year and larvae may be found at almost any time of the year. *-"*'\ i i' . \-h> x ^, li 1 '$fMr tUm&kJ* rr^fc • i \ w CfE * 'jmMr if if-\i i jKlr ! ' ■ ** — i B 1 ^F Jl jgifr vWkL, ■■■ • ,-;-. v . H ■■ JmF , *j9&3l£m «9Hbk. Hfr . * *r jjdfti - JgjSI Fig. 14. — Buds damaged by the larvae of the artichoke plume moth. Various methods of control by spraying and dusting have been tried but without success. Poisonous material cannot be applied safely because the irregular surface of the buds retains the poison indefinitely. Field sanitation is the best known method of control at present. Infested buds should be removed at every picking and burned or fed to livestock. Burning, plowing under deeply, or ensiling of the old plants after cutting in May or June, destroys many of the larvae. Thistles and wild artichoke plants harbor the insect and should be destroyed to eliminate breeding places. DISEASES Botrytis Sp. — The most serious disease of artichokes is a decay of the scales of the bud known as botrytis rot. One to several bud scales may be affected, the scales turning a light-brown color and the fungus developing a gray growth which eventually spreads to adjoining scales. This disease usually follows periods of rain, fog, or high humidity. There is no known method of control. Black Tip. — Black tip is apparently a physiological trouble associated with unfavorable environmental conditions. There is a blackening of the tips of the bud scales; the edible portion of the bud is not injured but the appearance lowers its salability. At present there is no known method of control. 24 California Agricultural Extension Service [ Cir - 76 Yellows. — This name has been given to a disease of the artichoke plant which has appeared at two widely separated points in the California coast region. After several years' observation, however, the disease has not seemed to spread from the original localities and in one location has entirely disappeared. Figure 15 illustrates the dwarfing effect of the •? *? ' / *" Fig. 15. — The plant in the foreground is affected with artichoke yellows. Note the dwarfing effect of this disease. yellows disease. The plants are pale in color, and the leaves have a curly or "crinkly" appearance. The flower stems are shortened and the buds poorly developed. The characteristic symptoms of artichoke yellows are very similar to those of sugar-beet curly top and aster yellows. It appears to be a virus disease, but to date this has not been proved. It would be a wise precaution to destroy every artichoke plant which shows yellows just as soon as the disease is observed. Propagating material should not be used from plants or fields which show symptoms of this disease. 12w-9,'33