CALIFORNIA AGRICULTURAL EXTENSION SERVICE PRODUCTION OF W'^^% :^ a<.^- H. M. BUTTERFIELD ^- COVER ILLUSTRATION Fig. 1. — Croft lilies grown in the mother-block system. Note that each mother bull) has from 5 to 7 bulblets growing next to it. 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. These factors govern the successful commercial production of Easter lily bulbs: • Climate should offer relatively low, equable temperature, with a minimum annual rainfall of 70 inches. • Land — preferably sandy loam — should be porous, friable, and well- drained. There should be three to four times as much land as is needed for planting in any one year. This permits rotation, which aids in control of pests and diseases. • A covercrop should be grown on the land the year before lilies are grown. • The mother-block system should be used to assure healthy bulbs, true to a desirable marketable type, with variety maintained. • Mixed or diseased stock must be rogued out. • Machine-harvesting is necessary on large acreage. • Harvested bulbs must be graded carefully for quality and size. • Bulbs must be shipped to eastern buyers in sufficient time to meet the variable dates of Easter. • Follow-up information on the results of forcing should be secured from eastern buyers. • The test of a California Easter lily bulb is in the forcing process in an eastern greenhouse. Satisfactory forcing by the eastern buyer assures the success of the industry in California. Therefore, every grower should have sufficient information on the culture of Easter lilies to know that the stock he is planting is reasonably free from inherited weaknesses, nematodes, and serious diseases. And he should also know that the actual production processes he plans to use have been tried and proved sound. CONTENTS PAGE What are Easter lilies ? 5 The Croft Easter lily 6 The Ace Easter lily 6 The Estate lily 7 The Creole lily 7 The Kenyon-Davidson lilies 7 Other lily varieties 8 The market demand for Easter lily bulbs 8 The price situation 10 Land values 12 Soil types 13 Rainfall and moisture supply 13 Selection of planting stock 13 Mother-block system 14 Planting the mother block 15 Planting bulb scales 15 Planting lily bulbs 16 Soil management 17 Pest control 18 Aphids 18 BracJiyrhinus beetle 19 Lily weevil 19 Thrips 19 Nematodes 19 Eabbits, gophers, and moles 20 Deer 20 Disease control 21 Black scale (brown scale, brown bulb) 21 Botrytis blight 22 Scale tip rot 23 Molds 23 Fusarium rot 23 Sclerotium rot (southern root rot) 23 Virus diseases 24 Lily rosette 24 Lily mottle 24 Necrotic fleck 25 Other diseases 26 Bunchy top 26 Yellow top 26 Eoguing 26 Suckers 26 Harvesting Easter lily bulbs 26 Separating and grading lily bulbs .' 27 Storage problems 31 Acknowledgments 32 References 33 [4] PRODUCTION OF EASTER LILY BULBS H. M. BUTTERFIELD^ WHAT ARE EASTER LILIES? Certain varieties of lily bulbs are forced in greenhouses so that the flowering plants will be ready for sale at Easter time. These lilies are called Easter lilies. Most of the varieties used for this purpose belong to Lilium longiflorum. The Bermuda lily is L. longiflorum var. eximium {L. harrisii). The variety grown largely in Jaj^an in past years is L. longiflorum var. giganteum, and is often referred to by commercial growers as the Gig lily. Other forms which have been grown include L. longiflorum var. insulare {L. formosum — Pormosum type) . The Erabu (L. erahu) is a fioriferous form of this popular Easter lily, and the Croft variety (fig. 2) is reported to be a seedling of Erabu. Various other lilies have been grown commercially in the United States, such as the Ace, Estate, Creole (Floridi, Ellender, Peerless), and Kenyon- Davidson strain, in addition to hardy lilies of other species. Since the Ken- yon-Davidson strain involves a large number of seedlings, and these seedlings flower over a long season, some growers have hoped that the strain might be- come important for cut-flower purposes. But the Creole, Estate, and Kenyon- Davidson lilies are not suitable for pot lilies. Only lilies like the Croft and Ace, which can be forced to bloom for Easter, are satisfactory for pot lilies. The supply of planting stock has naturally affected choice among the lilies just mentioned. The Croft variety of Easter lily has been most popular, not because it is superior to the Ace, but because it has been the only variety of which there was stock for sale in considerable quantity. Where a choice be- tween varieties is possible, the prospective grower should be aw^are of the facts discussed under the different kinds of Easter lilies. ^ Specialist in Agricultural Extension. [5] California Agricultural Extension Circular 132 Fig. 2. — The Croft Easter lily THE CROFT EASTER LILY The Croft lily (fig. 2) takes its name from Sydney N. Croft, who first grew the variety on a commercial scale at Bandon, in southern Oregon, from a bulb given him in 1928 by Louis S. Houghton. Mr. Croft distributed planting stock to a few growers before his death. The plant of the Croft variety is pyramidal in shape, the leaves are long and flat, the flowers are bell-shaped, with width a little less than the length, leaves green, and pistil extended about 1.3 inches beyond the stamens. THE ACE EASTER LILY The Ace, properly known as Slocum's Ace, is distinctly different from the Croft variety. It was grown along with other lilies in the garden of Mrs. Dan Plymale, a collector of foreign lilies, at Bandon, Oregon. In 1935, Mrs. Plymale gave this lily to Clark Slocum of Langlois, Oregon, who propagated it by the mother-block system (see discussion of the mother-block system, p. 14) . Later, a Chicago buyer tested the variety in his greenhouses, and considered it to be outstanding for potting purposes. He encouraged Mr. Slocum to propagate Production of Easter Lily Bulbs 7 it commercially, which Mr. Slocum did. Because of his part in developing this commercial variety, it has been called Slocum's Ace. Like the Croft variety, the Ace is pyramidal in the initial stages of growth. The foliage appears' to be a little darker green than that of the Croft; the leaves are aJso long, but appear narrower because they are inclined to fold longitudinally. The leaves are somewhat mottled in the early stages of growth, but in time become dark green. The plants are about the same height as the Croft, which means anywhere from 6 to 24 inches, depending upon size of the bulb and growing conditions. Both the Croft and the Ace are shorter than the Creole and Estate lilies. The flowers of the Ace are bell-shaped, with the width equal to, or greater, than the length, but the pistil extends only about 0.6 inch beyond the stamens, which is much less than for the Croft variety. The variety is considered one of the best for potted Easter sales. It holds its leaves at an angle that permits a little closer spacing in the greenhouse than does the Croft. THE ESTATE LILY The Estate lily was also grown by Mr. Croft. Prior to 1935, he referred to it as tall and to the Croft as short. After he had segregated the tall Estate lily from the short Croft lily, all of the stock of the Estate was sold to W. L. Crissey of Brookings, Oregon. About 1939, it was introduced into the garden trade by Edgar L. Kline of Oswego, Oregon. Plants of the Estate lily are columnar ; the leaves are very short and are yellowish green. The flowers are trumpet-shaped, with the width noticeably less than the length of the trumpet. The pistil extends about 0.6 inch beyond the red stamens in the opening buds, in this character more like the Ace than the Croft. The flower buds of both the Croft and the Estate are sometimes tinged pink while in the 2- to 3-inch-bud stage. The Estate is primarily a cut- flower variety. THE CREOLE LILY The Creole lily has been used as a garden and cut-flower lily in the vicinity of New Orleans for at least fifty years. The plants are columnar in shape, like the Estate; the leaves are short and green and usually mottled. The stems are uniformly green. The flowers are bell-shaped, with the width slightly less than the length, and they are consistently smaller than the flowers of the Croft. The inner edge of the petals appears to be frayed — an illusion created by the pres- ence of transparent areas. This feature helps to distinguish the Creole from the Mexican variety, Shangri-La or Mexicana. The Creole is used primarily as a cut-flower lily and now leads all others in the number of bulbs grown. The bulbs usually sell for much less than the California A-arieties, which may have considerable to do with the profit made by the commercial greenhouse operator. THE KENYON-DAVIDSON LILIES Of the many seedling lilies developed by Dr. David Grifliths of the LTnited States Department of Agriculture, one group of more than thirty seedlings was grown by Mr. Kenyon and Mr. Davidson ; these are known as the Kenyon- Davidson lilies. Being a group of seedlings, and not a distinct variety, they 8 California Agricultural Extension Circular 132 will vary in season of bloom when forced. A few have already been segregated by growers as being superior, and it is conceivable that they may become popu- lar in time, but at present their apparent value is in extending the season for cut flowers rather than being used as potted lilies for sale at Easter. OTHER LILY VARIETIES The Bermuda lily is not promising for local culture. In fact, to import any lily that may harbor a serious virus disease not common in local plantings is highly dangerous. The Bermuda lily has declined in popularity, largely be- cause it is often affected with one or more of the virus diseases. The future of the Easter lily bulb industry on the Pacific Coast depends on excluding serious virus diseases that will render the bulbs unfit for use as potted plants at Easter time. New seedling Easter lilies may appear in the future and secure the popular approval of commercial florists ; but, in order to receive much attention from florists, a new variety must stand shipping and forcing, and must produce a satisfactory number of buds in time for Easter. It must be relatively free from serious defects or diseases. A variety that is a healthy green, is compact so that it takes the minimum amount of room on greenhouse benches, yet has a satisfactory number of large flowers of good form and color, will likely win the approval of florists. The producer must not only be interested in the ability of the variety to propagate well ; he must also be assured that the bulbs are relatively free from disease, that there are no mixtures, and that the size of the bulbs offered for sale is large enough to produce a good average number of buds after being forced. Incidentally, the price asked for the bulbs must be in keeping with what experienced florists can expect in the way of prices on their regular markets. Usually, the cost of the bulb should be correlated with the number of buds produced after forcing, and the standard for a seed- ling should take such factors into account. As the supply of Easter lily bulbs increases, buyers will become more and more particular about the ability of the bulbs to stand forcing and to produce a large number of buds of good quality ; they will demand bulbs with healthy scales, good shape, good roots, and at least one good nose (fig. 3). THE MARKET DEMAND FOR EASTER LILY BULBS' Growers in the United States imported an average of 23V2-niillion lily bulbs each year during the five-year period ending 1940. Most of these bulbs came from Japan. Of this number, perhaps 10- to 12-million bulbs were used for potted plants at Easter time. The actual number used for potting purposes may range as low as 8 million. A very marked decline in lily bulb importations occurred in 1941, when the number was 1,750,896 — a drop from 26,283,943 in 1940. This drop was due not only to a decline in imports, but also in demand on certain United States markets. In 1944, this country imported 1,335,755 lily bulbs from -Mexico, 694,995 bulbs from Bermuda, and a smaller number from Canada, Cuba, and the United Kingdom, making a total in imports of 2,050,688 bulbs, valued at $285,963. In 1945, Mexico shipped to this country - Volumes of Monthly Summary of Foreign Commerce of the United States. Compiled by Division Foreign Trade Statistics. Production of Easter Lily Bulbs Fig. 3. — A desirable bulb has healthy scales, good shape, good roots, and at least one good nose. Note the compact rounded scales on the specimens shown. 1,664,011 bulbs, tlie Netherlands, 611,778, and Bermuda, 51JL>,785, with im- ports totaling 2,983,968 lily bulbs, valued at $434,833. The figures for the first few months of 1946 are not very significant as far as potted Easter lily bulbs are concerned, because it was too late to force bulbs. However, the Netherlands shipped 122,450 bulbs in January, with a value of $19,498, and continued to dominate imports through February, March, and April. Of more significance than the number of bulbs imported, is the attitude of important eastern florists toward California Easter lily bulbs. On some of the large American markets, two thirds of the Easter lily bulbs grown were of the Creole variety, with Crofts ranking next. It has been estimated that in 1943 about 7- to 10-million lily bulbs were forced for pot sale, and a similar number were grown in 1944. In 1945 the number was estimated at 5 to 7 mil- lion, and in 1946 at around 3-million bulbs. A report on the St. Louis market for 1946 indicated that no potted Easter lilies were grown. Some large forcers report a profit on Creole and a loss on Croft. A large Pennsylvania grower who had forced as many as a million bulbs in past years potted only 12,000 in 1946, 10 California Agricultural Extension Circular 132 about 2,000 of which were unsold because of low bud count. In many florist shops, at Easter time, profits have been on the sale of plants other than Easter lilies. In normal times, florists have used from 20- to 29-million lily bulbs, and have forced up to 10-million bulbs a year for pot purposes. Approximately 20-mil- lion bulbs out of the total were sold to large eastern buyers. Recent sales on the Pacific Coast were estimated at about 200,000 a year. If these estimates are approximately correct, then lily bulb growers on the Pacific Coast should cater to the demands of the larger buyers. Growers should produce lily bulbs that can be sold at a profit by the more important florists. The real test of a California lily bulb is in the forcing process in an eastern greenhouse. If the plants average only 2 to 3 buds when forced, it is hard to see how demand can be maintained at any price. It is not a question of the number of buds on a forced plant in some California greenhouse, but rather what the average is in the eastern greenhouses where most of the bulbs are sold ; so growers as a whole must think in terms of satisfying the large eastern demand. The claim of the California grower that the eastern forcer has trouble because he does not force the bulbs properly is questionable, because a man with years of experience in forcing probably knows more about this end of the business than anybody else. Failure to follow the history of the bulbs through to the final forcer is a very shortsighted sales policy, and one most likely to lead to disaster for all who are engaged in the process. What happens to one group of producers may happen to all, regardless of where the fault lies, unless the sales organization can clearly prove that the lily bulbs offered for sale have a very fine record at the forcing end and are true to name. The market demand may be seriously injured by misleading publicity. Some of the articles written have mentioned large profits to growers on the Pacific Coast. Important buyers who have been unable to secure a fair per- centage of salable plants, or who have not averaged more than 2 to 3 buds per plant, after paying up to 80 cents a bulb, naturally frown when reading such publicity. Profits must be shared all along the line if market demand is to be maintained. Growers as a whole should do all they can to see that they are not placed in a false light regarding profits, as long as high prices to buyers prevail. They should remember that Creole bulbs ripen as much as 2 to 3 months ahead of Croft bulbs, and are sold at a much lower price ; there- fore, if demand for Pacific Coast bulbs is to be increased, growers will have to consider some of these adverse marketing conditions. THE PRICE SITUATION A limited supply of lily bulbs, combined with good demand, has caused bulb prices to soar to a very high figure. The price range for different sizes and grades of Croft lilies, reported in 1944 by growers in the Pacific Coast area, is shown on the next page. Prices for 1945 were similar. Prices to growers for the 1946 crop of Easter lily bulbs cannot be reported until the entire crop has been sold. At the start of the 1946 seasoJi, demand seemed to lag somewhat, and some growers were fearful that part of the crop would remain unsold at the prices mentioned. Prices to the grower include the following for the 1946 crop : 40 cents for 7-inch, 50 cents for 8-inch, Production of Easter Lily Bulbs 11 66% cents for 9-inch, and 82 cents for 10-inch sizes. But supply and demand will regulate the final price paid to the grower. Many eastern growers claim that only bulbs as large as 8 inches will force satisfactorily and produce enough buds to make the plant a profitable sales product. Commercial florists have not forgotten prewar prices for the imported bulbs, 1944 Price to Grower for Croft Lily Bulbs (Size refers to inches in circumference) Bulblet planting stock Price per bulb (Size) (Cents) Smallest 5-10 Largest 15-25 Yearling bulbs (Size in inches) 3 25-35 4 30-40 5 35-40 Bulbs used for forcing (Size in inches) 6 40-45 7 60-70 8 70 9 70-80 10 80-90 11 90-$1.00 when a 6-inch bulb sold for 3 to 3% cents, a 7-inch bulb for 3% to 4 cents, an 8-inch bulb at about 4I/2 cents, and a 9- to 10-inch bulb around 5 cents. Nat- urally, experienced growers have expected a gradual reduction in price, following the end of the war, although readjustments may take place slowly. Some growers are wondering if Japanese lily bulbs suddenly will be admitted again, and what effect their entry would have on prices. Price per bulb is only one of several important factors that affect profits to the forcer. Cost per flower bud is a better criterion forjudging a reasonable price than cost of the bulb alone. For instance, if a high-quality Pacific Coast Easter lily bulb that forces well could be bought at a reasonable price, a florist is not blind to the fact that it would be a far more profitable purchase than an inferior imported bulb. Growers of lily bulbs therefore should try to meas- ure relative values in this way, and should try to justify price in relation to the cost per flower bud at the retail end. For example, if a forced Easter lily is valued at 50 cents per bud, on up to as much as $1.00 per bud, and a 9- to 10-incli bulb produces 5 good buds, such a plant might be valued at from $2.50 to $5.00 wholesale. When, for such a plant, a bulb sells for 85 cents, it might be a better purchase than another bulb selling for 40 cents, if the latter pro- duces only 2 to 3 buds. An extra investment of 40 to 50 cents a bulb might actually pay handsome dividends. As a line of argument, however, it may be true or false, depending upon results obtained. Because of the factor of un- certainty in the results, it is very important that Pacific Coast lily bulb growers know what results are obtained by the forcer of the bulbs sold. Easter lilies produce small bulblets on the stem above the mother bulb, and these bulblets are the ones used for planting stock. The more favorable the growing conditions are, and the larger the bulbs planted, the more bulblets the 12 California Agricultural Extension Circular 132 grower can expect. Very small, immature bnlblets may be hard to sell at any price, but the larger bulblets have sold for as much as 15 to 25 cents each, and the smaller sizes up to 5 or 10 cents each. Planting stock has been sold for $6.00 to $12.00 a pound. The small, immature bulblets sold during the time of scarcity brought as much as 1^/^ to 5 cents each, and were occasionally sold as a cluster attached to the mother stem for about 1^/2 to 5 cents a cluster. But if these small bulblets require a third year in which to reach a salable size — as is usually the case — they are probably less economical than the larger bulbs at the prevailing price. It should be remembered that many lily bulb growers secure most of their profit from the sale of bulblets rather than bulbs of forcing size. LAND VALUES Land values usually go up during the booms which follow wars. Land suit- able for Easter lily bulb production has been no exception. Near the coast in northern California, sandy-loam land which was hard to sell a few years ago at $75.00 an acre has recently changed hands for as much as $1,000.00, or more, an acre. Rentals for land have been as high as $125.00 an acre per year. Be- ginners should realize that they need from three to four times as much land for rotation as is planted to Easter lily bulbs in any one year. This is to allow a minimum of two years between crops — a practice recommended by those most familiar with the control of bulb diseases and pests. For instance, the dangers of bud and leaf nematodes and soil-borne diseases demand that a mini- mum of two years between crops be allowed. So the total investment in land should be considered with this thought in mind. Continuous planting on the same piece of ground, year after year, can lead only to trouble. SOIL TYPES Land used for lily bulb production in the Dows Prairie section of Humboldt County is of the Rohnerville sandy-loam type. A little to the north, in the Crannell section, the land is of the Empire sandy-loam type. Such sandy loams are often low in available nitrogen and have to be fertilized heavily. Crops may differ greatly within a distance of a mile, due to irrigation facilities and natural fertility. Lands in Del Norte County (fig. 4) being cleared of trees for bulb production may be low in fertility at the start. Since the bulbs are usually planted in the fall, it becomes essential to select land that is well drained in winter. If not well drained at the start, land may need tile drainage, a procedure that requires extra investment. Level land that has facilities for irrigation will add to the value of the property, because such facilities may be good insurance in dry years. All such factors should be taken into account when judging land values. It is a serious mistake to estimate values solely on the basis of high bulb prices. A much safer way would be to estimate values for the land in accordance with what the land could be used for if lily bulbs were no longer a paying enterprise. The investor at least should consider what might happen if he could not grow lily bulbs. The actual price paid for the land is not so important as liquidating the indebtedness while bulb prices and net income are still good. Inflated land values are always dangerous, because nobody can accurately predict how long high bulb prices Production of Easter Lily Bulbs 13 will continue. Any serious drop in bulb prices or in land prices before the land has been paid for might leave the nominal owner with little, or no, equity in his property. That has happened before in some agricultural enterprises and could easily happen in lily bulb production. RAINFALL AND MOISTURE SUPPLY A minimum annual rainfall for Easter lily bulb production has been set at about 70 inches. Where the normal rainfall is not enough to maintain proper growth during June, July, and early August, supplementary irrigation will be needed, but this, in turn, increases the hazard from botrytis leaf spot, and runs up the cost of production. Most growers do not irrigate, even though a dependable supply of irrigation water would be good insurance along the northern California coast where lily bulbs are grown. Without a high annual rainfall, there is little hope that lily bulbs could be grown at a profit. Furrow irrigation is suggested wherever the land and irrigation facilities make this method feasible. SELECTION OF THE PLANTING STOCK Few beginners have paid enough attention to the quality of planting stock (bulblets) (fig. 5). Every grower should have sufficient information to know that the stock he is planting is reasonably free from inherited weaknesses, nematodes, and serious diseases. Every grower should insist on obtaining a record of the planting stock purchased; this should include the true name of the variety, who grew it and where, to what extent the bulbs were culled or Fig. 4 — The small planting of Easter lily bulbs on a family farm has frequently been a profitable side-line enterprise. (A planting at Fort Dick in Del Norte County.) ,^^^ 14 California Agricultural Extension Circular 132 rogiied ill the fields, and to what extent the field was infested with bud and ]eaf nematodes. Bulblets consisting of mixed varieties lead to trouble later on. Off-type bulbs are common in many plantings, and this trouble ultimately extends to the florist who forces the bulbs. He has a right to complain when he purchases bulbs under one name, only to find out later that they were a mixed lot. The future of the American lily bulb industry depends on starting with healthy bulbs that are true to a de- sirable market type and variety. Such a standard can be maintained by using the mother-block system. MOTHER-BLOCK SYSTEM The mother-block system of lily bulb culture (fig. 1, cover) is designed to keep the original stock true to type and free from disease. It consists of select- ing the best bulbs for propagation pur- poses only. In turn, the mother block will furnish stock for the commercial bulbs sold. As described by those fa- miliar with this business, the mother- block system holds the stock true to type, eliminates much roguing, pre- vents stock from running out, and is the best method for controlling virus dis- eases. Since the mother block is usually isolated, it can more easily be kept free from diseases, but should disease de- velop, affected plants are easy to find. The number of units to start with in the mother-block system should be not less than 100, nor more than 1,000.'' A unit is defined as a mother bulb and all the stem bulblets. The units for the mother block may be selected plants which are 4 inches high, according to the following characteristics: 1) outstanding vigor, 2) uniformity in type (symmetrical pyramid habit in the Croft lily), 3) uniformly dark green leaves, and 4) little or no botrytis blight in the field. All plants selected should be marked in some way. About 4 weeks before the blooming period, the bulbs should be regraded according to the four points just given. All plants tending to mature too early should be separated from the mother block and discarded. Only the plants which are symmetrical and which have a single growing point should be kept. Such grading may eliminate as much as 15 per cent of the plants marked at the first grading. The plants should again be graded when they are in flower, with close attention given to the leaves, to whether or not the plant is free from botrytis blight, and to the time of maturity. ^ Eecommendations based on those of Oregon Agricultural Experiment Station. rig. 5. — Planting stock is best supplied from a mother block, and the healthy mother bulb should have at least 6 bulblets on the stem as shown. Note the healthy ap- pearance and good shape of bulb and bulblets. Production of Easter Lily Bulbs 15 At the time of flowering, the plants tentatively selected are carefully in- spected to be sure that the first flowers open within a day or two of one an- other, and that the flowers are typical of the variety to be grown. This grading, at the time of flowering, may eliminate another 10 per cent of the original number of plants. To avoid further danger of botrytis infection from decaying flowers, the flowers are removed as soon as they have opened. At digging time, the selected bulbs are carefully dug and laid side by side for easy comparison. Some bulbs may form very few good bulblets, others may vary in appearance, and still others may vary in the amount of scale rots or other defects. The bulbs are rearranged according to one of these points at a time. At the end of the final selection, about 50 per cent of the original plants marked should be uni- form in the production of large bulblets — about 6 to a stem. Only bulbs free from scale rots should be selected, with bulbs that are misshapen or that have too many growing points (noses) left out. Each bulb, with its attached bulblets is then put into a small sack by itself. This is then labeled with a distinguishing number or mark for future identification. These family units are maintained in the mother block at least 100 yards distant from commercial plantings. A location where lilies have recently been grown should never be used for the mother block. Under favorable conditions, the planting should be left in for two years. PLANTING THE MOTHER BLOCK Planting should be done in rows, with the mother bulb first and from 5 to 7 of the best bulblets next. They should be spaced at least 7 inches apart, with the mother bulb set much deeper than the bulblets. The plants are scored when they are up in the spring. Any unit which fails to measure up to the standards already mentioned should be removed, or any unit that fails to germinate well, discarded. The bulbs are left in the ground at the end of the season, and all new stem bulblets are planted alongside the mother block. At the end of two years there should be about 20 lily bulbs for each of the bulbs planted at the start. After the first two years, the mother block is planted with the selected bulbs, but without keeping the family units separate. This planting will con- tinue to provide the chief source of planting stock for growing commercial bulbs. PLANTING BULB SCALES The outer bulb scales are used for rapid increase. Scaling is the term applied to this method of propagation. Under favorable conditions, each scale removed will form a small bulb at the base — sometimes more than one small bulb. The scales may be removed in the fall, about late October, and if not more than two of the outside layers — 12 to 15 scales — are removed, the bulbs will not be injured. The scales must be clean and healthy. They are piled loosely in shallow trays and covered with cheesecloth ; then a layer of moist peat moss is spread over the cloth to a depth of about 1 inch. The peat moss should be barely moist. The trays are then stacked as they are filled, and are kept at about 50° to 60° F until the scales begin to form bulblets. The scales, wdth bulblets attached, are planted in prepared beds or rows during favorable weather in January or February, or possibly as late as March. February has been a good time in coastal districts in Oregon. The 16 California Agricultural Extension Circular 132 scales, when planted, should already have begun to form bulblets with tiny roots attached. Two inches apart is adequate spacing if they are left in for only a year, but 4 inches apart is a better distance if they are left in for two years. The bulblets and scales should then be covered from IVo to 2 inches deep. Northern growers find that the bulblets grow well when covered with about a half inch of loam and an inch of weed-free sand. If planted 4 inches apart in the row, and grown under favorable conditions, the lily bulb scales should produce very vigorous bulbs at the end of two years. PLANTING LILY BULBS The spacing of lily bulbs varies according to the type of tillage tool used. Rows have been spaced from a minimum of 24 inches, center to center, up to 34, 38, and 44 inches, center to center. A tractor would require certain definite spacing and this would vary with the machine. Bulblets may be planted in a single row or staggered in two rows, or planted as a band in the row. If digging machines are used, the single row has certain advantages. Machines for planting have not been used to any important extent up to the present, but, as the size of the bulb farm increases, the importance of machine-planting to save labor will increase. The minimum allowance per acre for planting stock is 40,000 to 50,000 bulbs, and with the smallest sizes, the number may reach 100,000 bulblets per acre. The yearling bulbs are set farther apart, with the number per acre esti- mated at about 20,000 to 22,000. With rows as close as 24 inches, and bulbs spaced 12 inches apart in the row, an acre would hold 21,780 bulbs. With rows spaced as much as 44 inches apart, and bulbs only 8 inches apart in the row, the number per acre would be less than 15,000. With rows spaced 34 inches apart, and bulbs 8 inches apart in the row, the number of bulbs per acre would be about 23,000. This will give some idea of variations in spacing. The depth of planting varies with the size of the bulb or bulblet, the type of soil, the climate, and the purpose for which the bulb is being grown. The largest bulbs are planted to a depth of 6 to 8 inches to the top of the bulb ; yearlings, 4 to 6 inches, and bulblets, 3 to 4 inches. Soil should be prepared well below this depth to allow for the depth of the bulb. Since winter tempera- tures are mild in the lily bulb districts of the Pacific Coast, there is not the need for deep planting as there is in areas where the surface soil freezes. Bulbs will probably size up best when not planted too deep, but the bulblet increase is often best with deep planting. It is safer to plant deep in sandy-loam soils than in the heavier soil types. Lily bulbs should be planted by November 1, where conditions permit, be- cause early planting favors maximum growth of the bulbs. The continuation of early rains, labor scarcity, and similar difficulties may delay both harvest and the time of planting. Growers report that bulblets have grown satisfactorily when planted as late as December and even on January 1. If bulbs are dug before they reach full maturity, there is danger that they will not do so well later on. Some of the difficulty with blind bulbs is probably caused by bulbs not becoming fully dormant in districts with mild winters. Most bulbs are planted by hand. The bulblets are scattered along the furrow without trying to have their tops in an upright position. Large bulbs are Production of Easter Lily Bulbs 17 usually set by hand in an upright position and at the proper distance apart. To reduce labor cost in the future, machines no doubt will be used for planting large acreages. Machines used in planting potatoes might be adapted to plant- ing lily bulbs; however, possible damage to the scales must not be ignored. Most growers favor replanting each year, even the bulblets. It is hard and expensive to get rid of weeds in the row where the bulbs are not dug and replanted each year. Perennial weeds could interfere very seriously with har- vesting. Since early rooting is retarded by serious drying of the bulbs and the at- tached roots, the grower is advised to be ready to plant before he starts to dig. In that way, the bulblets or planting stock can be planted with a minimum amount of drying and injury. Workers should not dig the bulbs too far ahead of those who gather the bulbs and place them in boxes for hauling to sorting benches. This simple precaution can help a lot in giving the planting stock a good start. Facilities should be available for treating bulbs and bulblets for nematodes and diseases so that no unnecessary delay need be experienced in getting the bulbs into the ground. SOIL MANAGEMENT A common practice among lily bulb growers is to plant a covercrop on the land the year before growing lilies. This covercrop may consist of vetch, vetch and oats, or a similar combination that has been found successful in the lo- cality. Some growers report that they get two covercrops a year. The soil must be plowed in time to turn under the covercrop and get it ready for bulb planting by late October to early November. If delayed much beyond this period, heavy rains may cause plowing to be postponed indefinitely. A covercrop plowed under may not provide all the plant food needed by the larger bulbs. Some growers apply manure in generous amounts, and sup- plement this in the early growing season with mixed commercial fertilizers rich in nitrogen and phosphate. This is an excellent practice. The fertilizer may be bought already mixed or may be mixed on the farm. Many growers use bonemeal to some extent, even though it is normally an expensive source of nitrogen. It contains both nitrogen and phosphoric acid, which become avail- able slowly, making it safe to use and without serious waste. Blood meal has been used, in some cases, to provide an organic nitrogen fertilizer. Potash may be needed in small amounts, but large amounts may injure the foliage. In normal times, growers have a choice between different fertilizer mixtures, and should be able to decide which one is most economical under local condi- tions. Some lily bulb growers have used a 4-12-4 mixed fertilizer — one that contains 4 per cent nitrogen, 12 per cent phosphoric acid, and 4 per cent pot- ash. Such a mixed fertilizer, sold to the grower for $50.00 a ton, may be a less economical fertilizer than the 8-8-4 mixture at a somewhat higher price per ton, simply because the cost per ton of an 8 per cent nitrogen fertilizer is usually cheaper per unit of 20 pounds (1 per cent) of nitrogen — the element most likely to be deficient in many lily bulb soils. In most soils, the plants will also respond better to a double amount of the nitrogen than to a double amount of phosphorous and potash ; so doubling these other fertilizer elements is a waste of money. 18 California Agricultural Extension Circular 132 Growers should lay out test plots in areas where a good fertilizer program has not yet been fully determined. They should be familiar with the unit method of determining the relative cost of essential plant foods. Briefly, the formula may be given as follows : cost per ton divided by the percentage of the nutrient, equals cost of 20 pounds of the nutrient. An extra allowance should be made for the value of organic matter applied. When most, if not all, of the fertilizer is added before planting time, some of it will probably be wasted, so the plants will not get all they need in the growing season. This applies particularly to the commercial nitrogen fer- tilizers which may be leached out by heavy rains. As a general rule, phosphoric acid and potash will be retained in the soil. After the bulb sprouts and sends up a shoot, roots will develop along the stem above the mother bulb, and these roots will use available nitrogen close to the surface. The lily plants will prob- ably have their maximum plant-food intake in the growing season, about the time that the buds form, so a second side dressing of a nitrogen fertilizer some time in the spring should be a good practice to see if it will improve soils that are low in available nitrogen. Placing a band of commercial fertilizer 2 or 3 inches below the bulbs, and a similar distance to each side, has proved bene- ficial in growing various crops, although many lily bulb growers still apply the fertilizer with an ordinary spreader to the surface of the land before planting. Further information is needed on the best system of crop rotation on soils where lily bulbs are grown. The rotation may consist of covercrop, lily bulbs, and potatoes, or any similar combination that has been found desirable in the locality. Growers who can make a good living on a farm, when lily bulbs are omitted from the rotation, will be in a safe position, should these bulbs prove unprofitable in future years. Livestock and pasture may have a place in the rotation on the larger farms. Cultivation is needed to control weeds in lily fields. Weeds waste moisture and compete with the bulbs for available plant food ; they also interfere with harvesting operations. 9uch perennial weeds as sheep sorrel, Runiex acetosella, have been a real problem on some farms. An inexpensive control of weeds, before the new shoots of the Easter lily plant break through the soil, is with Diesel oil or stove oil, at the rate of up to 60 gallons per acre. The cost of this oil is loAV enough to aid greatly in reducing labor costs. Where tractors can be used for cultivation, weeds can be controlled in the space between the rows, but expensive hand- weeding is needed in the row itself to avoid injury to the bulbs. After the bulbs send out their roots, it is dangerous to cultivate very close to the row ; then, weeds have a chance to grow unless hand-weeding is practiced. With man labor costing up to $1.00 an hour, the grower is faced with serious expense. A wheel hoe is often used to control weeds in small plant- ings, and can be used to cover as much as an acre a day if weeds are not bad. PEST CONTROL Easter lily bulbs are attacked by various insects, nematodes, rodents, and deer. Aphids. — Aphids, or plant lice, are perhaps the most common pests and are especially feared because they may spread certain virus diseases. The cotton, Production of Easter Lily Bulbs 19 or melon, aphid, Aphis gossypii Glov.,' is responsible for the spread of necrotic fleck. The potato aphid, Mac7'osiphiim solanifolii (Ashm.), and the green peach aphid, Myzus persicae (Sulz.) , may carry the cucumber and lily mottle viruses, where these diseases are present and the insects become infective. Repeated applications of nicotine sprays will control these sucking insects. A native lily aphid in Humboldt County should be watched. Brachyrhinus Beetle. — A species of Brachyrhinus beetle, probably Brach- yrkinus sulcatus (Fab.), sometimes referred to by growers as the lily weevil, lays eggs under the leaves, aiid the larvae that develop work their way through the stem to the bulb and generally destroy it. This insect is found in Humboldt County, where it has caused some loss in lily fields. A poison apple bait has helped to control this pest when used at the time the adult beetles emerge — along in late May or June. Lily Weevil. — The lily weevil, Agasphaerops nigra Horn, resembles the Brachyrhinus beetle, and does considerable damage to the foliage of Easter lilies in the Pacific Northwest during late March to the middle of May. Stand- ard lead arsenate, 2 pounds to 50 gallons of water, and a mineral-oil spreader to make the spray stick well are recommended. The spray is applied first in late March or early April, and is repeated at 10-day intervals for about five applications, extending up to about May 15.' Thrips. — A species of thrips, Liothrips vaneeckei Pries., has been reported on lily bulbs from three places in California, and may become a pest on Easter lily bulbs. It can do considerable damage to bulbs in storage or in the field. Other insect pests, such as wireworms, may occasionally attack lilies, but to this time they have not been serious. Grubs have done some damage in lily beds, but moles may hold these in check. Nematodes. — A bud and leaf nematode, Aphelenchoides olesistus, has been associated with dieback in lilies, and the damage it causes is often referred to as dieback. This nematode is sometimes found in plants affected with bunchy top. Investigators studying this disease are now working on the hypothesis" that the symptoms — bunchy top — may be the result of bud infestation or infestation by the nematode at an early stage of growth, harming and destroy- ing certain cells in the young tip, or poisoning the plant to some degree. The same nematode is believed to be responsible for malformations of young shoots of the peony and for blindness of the flower buds. Late in the season, the nema- tode may not be located or may be located only occasionally in the peony plants. The strawberry nematode is responsible for a cauliflower effect oi;^ infested strawberry plants. The bud and leaf nematode which attacks lilies migrates, and there may be many opportunities for migration during the underground life of the lily. The problem is being studied further to see if there really is a close correlation between bunchy top and dieback of the lily. Bunchv top was formerly thought to be a virus disease, but is probably not, * Smith, F. F., and P. Brierley. Studies on lily virus diseases. Phytopathology 34: 529-55. 1944. •'^Doucette, C. P., and R. Latta. Lily weevil {Agasphaercyps nicjra) a potentially serious pest in the Pacific Northwest. IJ. S. Dept. Agr. Cir. 746:1-24. 1946. " In a letter, dated January 1, 1945, to the author from Dr. G. Steiner, Principal Nema- tologist in Charge, Division of Nematology, Bureau of Plant Industry, U. S. Horticultural Station, Beltsville, Md. 20 California Agricultural Extension Circular 132 because plants that exhibit bunchy top one year may not do so the next. Many lily growers have found that only a small percentage of the bunchy-top plants are diseased in the succeeding seasons. Lily bulbs that appear late in the field may be suspected of being infested with the bud and leaf nematode. Some growers place a small marker by such late plants, so they can be more closely watched. In lily fields where the bud and leaf nematode has been reasonably well controlled by the hot water treatment, an occasional plant has shown symp- toms of nematode infestation by a yellowing and a premature drying of the leaves. Roots attacked are badly injured. In one field of 6 acres, where these symptoms were observed, an examination was made in 1946 by M. W. Allen,' of the California Agricultural Experiment Station, which showed that the meadow nematode Pratylenchus pratensis (de Man) had been attacking the roots of the affected lily plants. G. Steiner* has also called attention to this pest which caused root destruction on lily and other plants. Such a nematode is not likely to become a primary consideration, especially where the bulbs are cooked to control the bud and leaf nematode, a treatment discussed in the following paragraph. However, this meadow nematode has caused some dam- age in commercial Easter lily fields. Proper rotation with other crops should help in the control. As far as possible, only healthy bulbs should be planted, and in soil where lily bulbs have not been grown for two years. Where bulbs have shown nema- tode infestation — in some cases as much as 70 to 80 per cent — treatment has consisted of holding the bulbs in a uniformly hot water bath at 110° to 111° F for one hour (fig. 6) . The thermometer used to determine the proper tempera- ture must be accurate at the temperature range mentioned. From year to year, all growers should test their thermometers, by comparison with a standard thermometer, to be sure the reading is correct at 110° to 111° F, and arrange- ments should be made for this service in the leading lily bulb growing areas where nematodes are a problem. Formaldehyde (formalin) is added to the water bath at the rate of 1 pint to 25 gallons of water. A separate cold dip with wettable Spergon to control basal rot will also be needed. The field should be gone over very carefully during the following season to rogue out any plants that are visibly affected with dieback or bunchy top. Rabbits, Gophers, and Moles. — Rabbits will nibble tender lily sprouts. Pocket gophers are a common pest. Moles loosen the soil in lily beds, causing it to dry out around the roots of the plants. The moles may do more good than harm, however, by destroying insects in the soil. One grower came to this con- clusion after trapping moles in his lily beds. But traps can be used effectively if these rodents become a nuisance. Deer. — Deer are troublesome in isolated areas, feeding mostly on the tender young lily tips. After the lily plants are up well, they are not so attractive to deer. Fencing and shooting are the two important methods for controlling deer that cause damage. An 8-foot fence made of wire netting would exclude deer, but it would be too expensive for most farms. ^ From personal comment by M. W. Allen, Associate in the Experiment Station. "^ Steiner, G. Meadow nematodes (Pratylenchus sp.) as the cause of root destruction. Phytopathology 35:935-37. 1945. Fig. (3. — A vat for dipping lily bulbs to control the bud and leaf nematode, AphelcncJioides olesistus, and also for the control of certain fungus troubles has become an essential part of the equipment in all Easter lily bulb producing areas. Provision should be made to regulate the temperature at 110° to 111° F. Equipment to make the dipping easy should be considered. DISEASE CONTROL The more important lily bulb diseases include black scale, botrytis blight, scale tip rot, molds, fusarium rot, sclerotium rot, and several virus diseases. Among the known virus diseases are lily rosette, lily mottle, and necrotic fleck. Two other troubles sometimes associated with virus disease are bunchy top and yellow top, although they have not yet been fully proved to be caused by a virus. For convenience, these diseases will be discussed in the order listed above, although this order is not necessarily in degree of importance. Black Scale (Brown Scale, Brown Bulb). — The fungus causing this dis- ease was first described as coming from Bermuda, but it has assumed impor- tance in Louisiana where it is known as brown scale, or brown bulb. Brown lesions appear on the outer bulb scales during the growing season, and the injury seems to be superficial. In storage, the darkened areas may become more extensive, extending deep into the outer scales. Buyers will refuse to accept badly affected bulbs, although mildly affected ones may force fairly well. Dr. A. G. Plakidas of the Louisiana State University has associated this disease with the fungus Collet otrichuni lilii. Since black scale is soil-borne and bulb-borne, it should be treated in the same way as that outlined for the more important disease, fusarium rot, described below. Avoid using bulbs affected with black scale, and do not plant again in affected soil for at least two years. 22 California Agricultural Extension Circular 132 Botrytis Blight (Botrytis Fire, or Leaf Spot) . This is a common fungus dis- ease on Easter lilies. The fungus Botrytis elliptica attacks leaves and flowers, causing spots to appear and, under moist conditions, possible general rotting of the leaves, buds, and stems so that the bulbs will stop growing. Control measures recommended include : 1) space adequately to prevent crowding, 2) avoid working around the plants when the foliage is w^et, and 3) remove flowers in the bud state or before they wither. Start spraying with bordeaux mixture, 4-4-50 plus a good spreading agent, when the plants are 3 inches out » M ^ h 1 a 1 1 ^ 1 1 M 1 $ Fig. 7. — Spraying for the control of aphids, botrytis blight, or other troubles re- quires the use of a handy spray outfit. The outfit here shown is suitable for the smaller plantings. of the ground, and keep the foliage covered during the wet spring weather (fig. 7). Penetrol — a spreading agent — emulsified separately with a small quantity of water, is added last, at the rate of 1 pint to 50 gallons (1 ounce to 3 gallons) of spray for spraying in the early season. If aphids are present, 40 per cent nicotine sulfate may be added to the mixture, at the rate of 1 pint to 100 gallons, or 1 ounce to 5 gallons. Insure good coverage by applying the spray under 200 pounds pressure, or better, and repeat often enough to cover new foliage. For a late season spray, the use of skim-milk spreaders has been recommended, using 4 ounces of hydrated lime in 2 quarts of skim milk. Allow a quart of this mixture for each 50 gallons of spray. Filter through a 20-mesh copper screen and allow to stand at least 30 minutes before using. Apply in a brass or noncorrosive spray tank. To prepare bordeaux mixture, first dissolve the copper sulfate (bluestone) in one container in a few gallons of water, then pour this solution into the spray tank, and add the full amount of water. Slake the rock lime in a separate container and, while the spray agitator is moving, pour the slaked lime into Production of Easter Lily Bulbs 23 the spray tank containing the bluestone solution. The two chemicals will react to form a high-quality bordeaux mixture. It is essential to add the full amount of water to the bluestone before adding the slaked lime, to avoid having the materials precipitate out in a short time. Always make the bordeaux mixture on the day it is to be used, because it will soon lose its value as a fungicide. Wash out the sprayer immediately after using it, because bordeaux is caustic and may corrode the spray tank. Scale Tip Rot. — This disease disfigures some Easter lily bulbs grown near the coast. Black lesions appear on the tips of central scales on freshly dug bulbs, and later, as the bulbs dry out more, the color changes to brown. Grow- ers do not consider the injury serious, as far as subsequent growth is concerned on the Croft variety, and yet the tip rot injures the appearance of the bulbs offered for sale and favors the entrance of the lesser bulb fly. Molds. — Molds may also gain entrance during shipment. Affected scales are unfit for propagation. This disease is most noticeable when the temperature remains around 50° F, and the bulbs are rather moist. Storing too many bulbs in a tight container may result in sweating and in favoring the growth of fungi responsible for scale tip rot. Fusarium Rot. — This disease has been the chief cause of decay in Easter lily bulbs during the growing season. A brown decay starts at the base of the scales, next to the basal plate, and forms what is commonly known as basal rot. The disease progresses until the scales fall away completely. Since stem roots form above the mother bulbs, the top of the plant may show little indication of this rot until it is very far advanced. The disease seems to be more destructive to planting stock than to bulbs of large size. The scales that fall away may develop bulblets, but these are often infected. Once rot has set in, the lesser bulb fly may attack, but this insect is a minor factor. Fusarium rot comes from diseased bulbs or from contaminated soil. Where this disease has been prevalent, the land should not be used again for growing lilies — not for at least three years or longer. A cold dip of a proprietary prod- uct known as Spergon is now a standard treatment. Spergon is practically insoluble in water but should be used with a strength of 1 part to 200 parts of water, or stronger, with a wetting agent added, and the bulbs should be wet for 2 minutes to coat them with this material. Treatment may last as long as 15 minutes. When the dip is half used, replace with a new lot. Bulbs should be reasonably clean when dipped. Keep the liquid stirred during treatment to insure an even coating over all the bulbs. The chemical is slowly activated after the bulbs are planted. Treat the bulbs separately from those given the hot water treatment for nematodes. In the use of Spergon, no injury to operators has been noticed. Sclerotium Rot, or Southern Root Rot. — The disease is caused by the fun- gus Sclerotium rolfsii. It appears as a soft brown decay of the roots, stems, and bulbs, where the fungus exists. Plants attacked near the ground line may fall over before the upper leaves wilt. The' disease has frequently attacked sugar beets and occasionally other crops. There should be no alarm among lily growers if they will start with healthy bulbs, and plant on new land where lilies have not been grown before. Planting stock should be cleaned and selected. 24 California Agricultural Extension Circular 132 VIRUS DISEASES Several virus diseases have attacked Easter lilies, the more important being- lily rosette, mottle, and necrotic fleck. Bunchy top and yellow top have been mentioned along with virus troubles, although they have not been clearly proved to be caused by a virus. Virus diseases are caused by an infectious agent which is carried from dis- eased plants by insects, particularly by aphids, or plant lice, in the case of Easter lilies. Once these carrier insects, or vectors, have fed on a diseased lily piant, they become infective and are able to spread the disease to a healthy plant on which they later feed. Not until the insects have become infective will they cause the diseased condition. No lily virus disease is known to spread through seeds, but the bulblets on diseased lily plants carry the virus. Since seedlings do not come true to the mother plant, it is necessary to plant bulblets from the mother plant, and such bulblets must be healthy if these virus troubles are to be avoided. Once a bulb or bulblet becomes affected with a virus disease, it will always be diseased because there is no cure. That is why preven- tion is so important. Fortunately, experienced lily bulb growers are aware that these virus dis- eases have ruined Easter lily bulb plantings elsewhere, and that the future of the bulb industry on this coast depends on keeping planting stock healthy. The use of the mother-block system is the surest way to detect any possible introduction of any of these virus troubles and the surest way to escape pos- sible introduction. New bulbs should never be planted close to the older healthy bulbs. The mother block of bulbs should be kept at least 100 yards away from the nearest commercial planting. Any hope of the mother block escaping some of these serious virus diseases, in an area where diseased host plants and insect vectors are common, is considered very dim ; the location therefore be- comes an important consideration in escaping virus diseases. The potato aphid and green peach aphid transmit both cucumber mosaic and lily mottle viruses. Recent studies show that the cucumber virus has been transmitted to the Mari- posa tulip, Calochortus sp., Colchicuni aiitumnale, Fritillaria pudica, and Gloriosa, so these other bulbs may aid in spreading this virus to lilies where cucumber virus is prevalent. Lily Rosette (Yellow Flat). — This virus disease was first called yellow flat. It was the chief cause in the decline of Easter lilies in Bermuda between 1900 and 1920. Plants attacked are dwarfed, and the leaves turn yellow and curl downward in a conspicuous way. The flowers average smaller than normal. Fortunately this disease is not known to have occurred in California, but has been found in Florida. Rosette should not be confused with similar symptoms caused by poor soil drainage. The melon aphid is responsible for the spread of this virus disease, which will be hard to escape if it should appear in areas where the melon aphid is common. In no case should planting stock be used from areas where the disease may have been introduced. California plantings must be kept free from rosette. Lily Mottle. — All Easter lily bulbs are affected with some form of mottle virus. In some forms of the disease, the Easter lily leaves may develop coarse blotching, but in other cases the leaves show no outward symptoms. Several Production of Easter Lily Bulbs 25 species of aphids spread lily mottle. Mottle normally accompanies both necrotic fleck and lily rosette, but it is not a requisite to either of these other diseases. The disease normally spreads from one lily plant to another. It is very hard to detect because it may be masked under some climatic conditions. Fortunately for growers, this disease does not noticeably impair forcing qualities. The Creole variety usually shows some mottle, and the Ace shows a little mottle on the young leaves. Later the leaves turn green. Mottle disease that is rela- tively harmless to Easter lilies may ruin other lilies, so such lilies as Lilium tigrinum, forms of Lilium elegans, and Lilium formosanum are never safe when planted close to Easter lilies. A destructive variant of the mottle disease may develop from ordinary mottle. This virulent form causes serious blotches and stripes on the Easter lily leaves, and may reduce the leaves to awl-like projections, or deform and split the flowers. It is impossible to predict when or where this virulent form will strike. A low percentage of plants may develop it one year and show very little of it the next; some may develop the virulent form for the first time. Virulent mottle is considered just a variant of Easter lily mottle, and roguing out the plants will not necessarily get rid of the trouble. The same kind of aphids that spread the usual strain of mottle also spread the virulent form. All such pests should be avoided as far as possible and controlled, if they should appear, by spraying with nicotine sulfate. Necrotic Fleck. — Necrotic fleck may involve more than one kind of virus. Cucumber mosaic virus and a lily virus, which does not produce symptoms, are often present. Lily mottle viruses of the tulip virus group commonly ac- company necrotic fleck, but are not essential to the expression of fleck symp- toms. The melon or cotton aphid transmits necrotic fleck to lilies. Small brown spots, usually slightly elongated, appear on the diseased leaves. Diseased plants may be dwarfed, with curled foliage, so that they have to be culled out in the greenhouse. Mild and severe forms of the disease are reported. Plants with the mild form may be forced, but no flecked plants should be allowed to remain in the foundation stock. Fleck is believed to be a complex of two viruses ; one is the common cucumber virus and the other is the virus limited to Easter lilies. When the two are combined in the same lily plant . they pro- duce necrotic fleck. The melon aphid transmits the disease to healthy plants. Fortunately, the melon aphid is far less common in the northern areas, where Easter lily production is well developed, but in the warmer parts of California, where melons and similar host plants are common, this virus disease may be- come a limiting factor ; in fact, there is great risk in attempting to grow Easter lily bulbs in such warm areas. Control of necrotic fleck is possible through isolation and through the rogu- ing out of all diseased plants in areas where the melon aphid is not prevalent. All growers who have healthy stock should endeavor to keep it free from fleck. Spraying may retard the spread of the aphids that transmit the disease, but spraying is not an effective control by itself. Should the disease appear and plants have to be destroyed, the grower must be very careful not to scatter the infective aphids where they will set up new infection. A visibly diseased plant should never be left in the field; nor should planting stock from a greenhouse where the disease is prevalent ever be used. 26 California Agricultural Extension Circular 132 OTHER DISEASES Bunchy Top. — Plants affected with this disease emerge late, the leaves are thickened, awl-shaped, and lighter-colored than normal leaves, without being yellowed. Side growth develops at the tip of the main stem, giving rise to the common name of bunchy top. By the time the plant matures, the top resembles a feather duster. The flower buds that form usually abort, and the bunchy-top plants are a total loss to the florist. Bunchy-top disease has been known for several years on the Pacific Coast but, up to the present, the cause has not been fully determined. It may be a form of nematode injury, but tests have shown that bunchy-top plants in the field do not always give rise to bunchy -top plants in the greenhouse, yet grow- ers should select only normal plants for the mother block. If nematodes are a partial cause of bunchy top, they do not remain in the plant permanently. ( See reference to bunchy top under discussion on nematodes, p. 19.) The hot water treatment, which is needed wherever nematodes are present, is especially effec- tive if nematodes are in any way associated with bunchy-top disease. Yellow Top. — Growers of Creole lilies in the south are familiar with this disease. On affected plants, leaves develop bright yellow blotches. Later, a gen- eral growth takes place, followed by a premature dying downward from the top. Flowers may become spotted and distorted. Plants which show this dis- ease in the field may be normal when grown under glass, although some plants may reproduce the disease. The disease may spread in the field, so roguing out affected plants is suggested until more is known about the cause. ROGUING In spite of some precautions, planting stock may get mixed and include two, or more, varieties. The original stock of Croft was mixed and, unless all off- type bulbs are rogued out as soon as noticed, the mixture may continue. It is understandable why a grower will daub the foliage of a healthy bulb of a dif- ferent variety with some color to identify it, so that it may be segregated and sold later on, but this practice is dangerous. It is easy to miss such an offtype bulb at digging time. Certainly, all diseased bulbs should be rogued out promptly. The grower should never wait. And, unless he is able to separate all bulbs of a different variety at digging time, even these should be taken out as soon as discovered. The value of a few bulbs of a different variety hardly warrants the risk of continuing mixtures. Buyers have every right to expect that the bulbs purchased will be true to name. SUCKERS Sometimes lily plants send up suckers from the base of the plant. The ques- tion arises as to what should be done with these suckers. Most growers remove them promptly, so that the main stems will have no competition. It is believed that this treatment favors better bulbs and bulblets, although, to some extent, these suckers probably furnish elaborated plant foods to the roots. HARVESTING EASTER LILY BULBS Small lots of Easter lily bulbs — consisting of only an acre or two — are often harvested with a spading fork. One person to a row gently lifts the plant without hurting the bulb or bulblets, or seriously disturbing the roots. Other Fig. 8. — A storage place for lily bulbs, inachinerj, and other necessary equipment should be carefully planned. The one shown seems to serve the purpose very well. workers follow soon and place the clumps in boxes so that the roots will dry ont only slightly. In sandy soils, the dirt separates easily at harvest time. Large plantings should be harvested with a modified potato digger which has extra crossbars built in so that the bulbs will not fall through or be injured. A potato digger of this type, in a 26-inch width, works very well in sandy-loam soils, although weeds may clog the digger and delay operations. There is some danger that too many bulbs will be dug at a time, and that their roots will dry out excessively. This condition must be avoided. Workers should follow the digger, within a reasonable length of time, and pick up the clumps to be put into boxes which are scattered on the field. The tractor is used to pull the potato digger down the row, and to it can be hitched a sled, or other carrier, on which the boxes of harvested bulbs may be placed. The boxes of lily clumps should be hauled to benches where workers separate the large bulbs by hand. (See figure 8 for storage quarters.) Labor has been scarce and, when avail- able, has often been paid up to a dollar an hour for hand-digging. Even strong girls have been paid this amount for digging. State labor laws regulating the employment of children should be understood and complied with. SEPARATING AND GRADING LILY BULBS The boxes holding the clumps of bulbs are unloaded near tables located out- doors, or in sheds where women or girls remove the large bulbs from the clumps. If the bulbs have reached the proper stage of maturity, the stem should 28 California Agricultural Extension Circular 132 be pulled, or twisted, as gently as possible out of the top of the bulb. Should the stem not come free easily, then it should be cut off at the top of the bulb. Where the stem comes out easily, pulling by hand is preferred. There is less danger from rot if the stem is pulled out, unless it is very firmly attached. To avoid the danger of bruising — which may lead to rot — where a firmly attached stem is pulled out, a clipper or a knife should be used. The bulblets intended for planting should be shaded so they will not dry out any more than necessary in handling. All bulblets of a size suitable for planting are separated from the mother stem by hand. Many growers grade these into two sizes — large (No. 1) and small (No. 2). A third grade will in- clude all the small, white, rather immature bulblets that are less desirable for planting. These may be left intact on the mother stem and sold that way, or they may be separated at the last moment before planting. Some of these clumps have been planted on the stem when bulblets were scarce. The practice of wetting down the clumps of small bulblets should be thor- oughly condemned, because it may seriously increase any nematodes that might be present. It also favors bulb diseases. While this wetting does tend to increase the size of the bulblets and, in that way, may cause unsuspecting buyers to pay more, ^responsible growers and buyers should refuse to follow such practice. The grading of bulbs into various sizes is done either by hand, or by special grading machinery developed for the purpose. Yearling bulbs and older bulbs are graded according to circumference, and are listed in inches. Yearling bulbs may range in size from 3 to 5 inches, occasionally larger when growing condi- tions are most favorable. By the end of the second year, the bulbs should range from 6 to 10 inches in circumference. Bulbs ranging from 8 to 9 inches in cir- cumference should be listed as 8-inch bulbs. This size is about the minimum for forcing under some eastern conditions, simply because smaller bulbs have not produced enough buds to sell well. Possibly some of the bulbs ranging from 7 to 8 inches, and classed as 7-inch bulbs, may produce good plants on the Pacific Coast, where storage and shipping are not so hard on them. Bulbs ranging from 6 to 7 inches, and classed as 6-inch bulbs, are rarely fit for forc- ing, although quite a few were sold during the time when bulbs were scarce. These 6-inch bulbs should really be grown another year. In fact, growers can help their industry by withholding bulbs under 7 inches, and even under 8 inches, from the eastern trade until they are larger. These bulbs may be planted as late as spring, and will still have time to size up well. The grower must remember that most of the bulbs sold have to make good in an eastern greenhouse, where weather conditions are more severe than in most sections of the Pacific Coast. Starting the bulbs in pots outside a greenhouse — a prac- tice often followed in California — is hardly possible under eastern conditions ; such differences in growing conditions may account for the greater difficulty experienced by eastern growers in producing plenty of buds on the potted plants. This difficulty is all the more reason why careful grading should be done. To be ready for sale, a bulb should be a little larger than the scant mini- mum indicated by the grade. Planting stock has customarily been graded roughly into large (No. 1) and small (No. 2) sizes. Some growers have been careful to segregate any bulbs on Production of Easter Lily Bulbs 29 A marketable bulb is one of good size with tight healthy scales rounded into a short compact nose. A bulb with scales built up to abnormal height — sometimes referred to as Roman nose — is not desirable. A bulb with scales twisted into various A bulb with loose scales, not forming a patterns, and without one good nose is tight nose, is undesirable for forcing, not satisfactory for forcing. Fig. 9. — In grading bulbs, discard all that have scale rots or that are misshapen. which the upper scales were spread widely apart instead of closely clasping the tip of the bulb. These have been referred to as popcorn or crow's nest bulb- lets. Since they differ from the desired bulb, they may be either an offtype or possibly an undesirable bulb. A bulb with a very high crown — sometimes re- ferred to as a Roman nose — has been under suspicion in grading, although 30 California Agricultural Extension Circular 132 there is little evidence to show that some high-crown bulbs are actually dis- eased. Growing conditions may account for part of the difference ; however, in grading, it is important to grade for both size and shape to insure the maxi- mum uniformity in performance. (See figure 9.) IF EASTER FALLS ON DELIVERY TO RETAIL FLORIST STARTOF FORCING (FOR 13 WEEKS) IN HANDS OF WHOLESALE FLORIST START OF ROOTING (FOR 4-5 WEEKS) Fig. 10. — An adjustable planting calendar for Easter lily bulbs. Color as a factor in grading has been overemphasized at times. It is true that in the coastal areas many Croft lily bulbs are darker on the outside than growers like. Bulbs grown farther inland are often much whiter. The Estate may produce bulbs which, on the average, are a little whiter than the Croft. But such differences in color are not important, and the color cannot be fully controlled. Instead, the grower should concern himself more with discarding bulbs infested with nematodes or infected with the diseases already discussed, with treating the bulbs where chemicals are needed, and with roguing every year in the field to keep a pure strain in the mother block. The grower must remember that the bulbs forced in the eastern greenhouse will be no better Production of Easter Lily Bulbs 31 than the bulbs which came from the grading table or the grading machine on the Pacific Coast, and that, in addition, they probably will be weakened by long shipment and storage. STORAGE PROBLEMS All steps in the storing of bulbs should be taken with the thought in mind that the greenhouse operator must produce a potted plant with a satisfactory number of buds if he is to continue as a customer for Pacific Coast lily bulbs. The factors that affect the number of buds are somewhat antagonistic. Pre- cooling has been necessary in forcing Easter lily bulbs and, yet, holding the bulbs at a cold temperature for any great length of time will reduce the bud count. Another factor is early digging, which favors a high bud count. Lily bulbs must be dug in September or October in time for grading, packaging, ship- ping, and sale to greenhouse operators at distant points. The commercial florist knows that the potted Easter lily plant is a one-day plant, intended for sale a few days ahead of Easter. Since Easter comes on different dates, the forcer figures back from Easter date, approximately 13 weeks from the time the bulbs start to root (fig. 10). If Easter is on April 1, he would count back 5 months to November 1. Since many growers are through digging in September or early October, they are able to grade and ship the bulbs to the florists in plenty of time for forcing. It is possible for California forcers to plant in pots and set the pots outside for a slow, steady rooting to increase their vigor. Growers in cold climates do not have that opportunity and, as a result, the plants may have fewer buds. Bulbs are held around 54° to 56° F, for rooting, and such temperature may be found outside in parts of California early in the season after potting. Rooting in an eastern climate may be better at 60° F, or higher, than below, judging from bud counts. If the rooting takes a month, or more, before the 13-week period for forcing, a rough estimate of 17 weeks is the very minimum period in which the bulbs may reach the forcer ahead of Easter — assuming he has time to get the work done immediately. It would be better to allow at least 4^/2 to 5 months. Packaging and shipping will take some time, after the bulbs have been dug and graded. Cool storage is usually necessary for even growth and proper flowering by Easter. Considering Easter lilies in general, storing at 40° F for a month, if properly timed, will be safe. If the bulbs are held where the temperature does not go above 50° F for a month, the cool storage should stimulate early sprout- ing, early emergence, and early flowering ; but, it must be borne in mind, stor- age tends to reduce the bud count, so it should not continue for too long. A temperature of 60° F, or above, favors good root growth, so the storage tem- perature should not be that high. Growers without cold-storage facilities should seek some organization that will take care of this job. A cooperative organization can look after such details, including a temperature that will discourage not only premature sprouting, but also blind bulbs and storage rots. In past years, imported bulbs were packed in soil — a practice which encour- aged penicillium rot. To avoid this difficulty, calcium hypochlorite powder (20 to 27 per cent) was mixed with the packing soil at the rate of 160 grams to 50 pounds of soil. This mixture also controlled the bulb mite, Bhizoglyphus kya- 32 California Agricultural Extension Circular 132 cinthi Bdv. Perhaps the same treatment will help where packing materials other than soil are now used. Bulb mites, as well as bulb flies, may become a storage problem in the han- dling of Easter lily bulbs. It is a common practice to ship various kinds of bulbs in mixed car lots. Croft lilies have been fumigated, by the California State Department of Agriculture, with methyl bromide," at the rate of 3 pounds per 1,000 cubic feet for an exposure of 4 hours at 70° F. The relative humidity was 85 per cent. Treatment was given in October, and planting was done a week later. The Croft lilies given this treatment bloomed normally, with no difference in blooms noticeable at any time. This treatment for bulb flies and bulb mites on bulbs in storage or during shipment is feasible where fumigation equipment is available, but, because the gas is dangerous,'" it should not be used by any person without experience and the necessary equipment. ACKNOWLEDGMENTS The photographs shown in figures 1, 2, 5, 6, 7, and 8 were kindly furnished by Dr. Frank P. McWhorter of Oregon State College, Corvallis. Figure 4 is from Presley D. Tryon, Fort Dick, California. E. M. Fritz, Amadou Bulb Farm, Areata, supplied the bulbs shown in figure 3, and used for the drawings in figure 9. '' The hot water formalin treatment for nematodes is effective in destroying these mites ; so, where the bulbs have already been treated for nematodes, this methyl bromide treatment should not be required. ^"^ Based on report of the California State Department of Agriculture, July 21, 1943. Production of Easter Lily Bulbs 33 REFERENCES Bulletins and Circulars Breakey, E. p. 1945. Some suggestions on the harvesting and care of Croft Easter lily bulbs in the Pacific Northwest. State College of Washington, Western Washington [Agr.] Exp. Sta. (Puyallup, Wash.) Cir. 131:1-7. (Mimeo.) 1946. Some suggestions on the growing of Croft lily bulbs in the Pacific Northwest. West- ern Washington [Agr.] Exp, Sta. Cir. 134:1-6. (Mimeo.) Breakey, E. P., and A. S. Myhre. 1945. Croft lilies. Western Washington [Agr.] Exp. Sta. Cir. 127:1-3. Eevised. (Mimeo.) Cole, C. A. 1945. Oregon's Easter lily has reached the 'teen age. Oregon Agr. Exp. Sta. Bui. 147: 13-14. DoucETTE, C. P., and E. Latta. 1946. Lily weevil (Agasphaerops nigra) a potentially serious pest in the Pacific North- west. U. S. Dept. Agr. Cir. 746:1-24. Garma, Philip. 1937. A study of the bulb mite. Connecticut Agr. Exp. Sta. Bui. 402:889-904. Griffiths, David. 1921. The production of the Easter lily in northern climates. U. S. Dept. Agr. Bui. 962:1-31. 1928. A score of easily propagated lilies. U. S. Dept. Agr. Cir. 23:1-35. 1930. The production of lily bulbs. U. S. Dept. Agr. Cir. 102:1-56. Hill, E. G. 1931. A survey of the United States bulb industry. U. S. Bur. Agr. Econ. 55 p. (Mimeo.) McWhorter, F. p., S. L. Emsweller, and Philip Brierley. 1944. Suggestions for growing Easter lily bulbs in the Pacific Northwest. Oregon Agr. Exp. Sta. Cir. 339:1-13. (Mimeo.) Oliver, G. W. 1903. The propagation of the Easter lily from seed. U. S. Bur. Plant Ind. Bui. 39:1-21. Pirone, p. p. 1939. Diseases of ornamental plants. New Jersey Agr. Exp. Sta. Cir. 385:1-80. (See pp. 39-42, "Lily.") Shippy, W. B. 1937. Factors affecting Easter lily flower production in Florida. Florida Agr. Exp. Sta. Bui. 312:1-19. Smith, E. E. 1940. Diseases of flowers and other ornamentals. California Agr. Ext. Cir. 118:1-108. (See pp. 39-40, "Lily.") White, H. E. 1940. The culture and forcing of Easter lilies. Massachusetts Agr. Exp. Sta. Bui. 376 : 1-20. Periodicals Bermuda Department of Agriculture. 1935. An experiment on cold storage of lily bulbs. Bermuda Dept. Agr. Bui. 14(7) : 52-54. Breakey, E. P. 1944. Effect of methyl bromide fumigation on the subsequent development of the Croft lily. Jour. Econ. Ent. 37:277-79. Brierley, Philip, and F. F. Smith. 1944. Studies on lily virus diseases : The necrotic-fleck complex in Lilium longiflorum. Phytopathology 34:529-55. 1945. Additional species of Lilium susceptible to lily rosette virus. Phytopathology 35: 129-31. Courtney, W. D. 1945. Nematode infection of Croft Easter lilies. Phytopathology 35:572. 34 California Agricultural Extension Circular 132 Courtney, W. D., and E. P. Breakey. 1945. Forcing lily bulbs after treatment for control of nematodes. Florists' Eev. 96(2496) : 37-38. Emsweller, S. L., and R. L. Pryor. 1943. Flower development in Creole Easter lilies stored at various temperatures. Amer. Soc. Hort. Sci. Proc. 42:598-604. IMLE, E. P. 1942. Bulb rot diseases of lilies. Amer. Hort. Soc. Yearbook 1942:30-41. Le Beau, F. J. 1946. The eradieant action of a fungicide on Collet otriclium lilii in lily bulbs. Phyto- pathology 36:391-93. (Discusses use of 10 per cent phenyl mercuri triethanol ammonium lactate for control of black scale fungus on lily bulbs.) McClellan, W. D., and N. W. Stuart. 1944. Fungicides for controlling bulb scale rot and as carriers for growth substances in the propagation of Easter lilies. Phytopathology 34:992-93. 1944. The use of fungicides and growth substances in the control of fusarium scale rot of lilies. Phytopathology 34:966-75. McWhorter, F. p., N. W. Stuart, and E. E. Clark. 1946. Cite characters of commercial lilies to aid identification. Florists' Eev. 98(2541): 27-28. O'Leary, K., and C. E. F. Guterman. 1937. Penicillium rot of lily bulbs and its control by calcium hypochlorite. Boyce Thomp- son Inst. (Yonkers, N.Y.) Contrib. 8:361-74.' Plakidas, a. G. 1944. Black scale: a disease of Easter lily bulbs. Phytopathology 34:556-71. Shippy, W. B. 1934. Treat lily bulbs with disinfectants to eliminate decay. Florists' Eev. 73(1888): 13-15. Smith, F. F., and Philip Brierley. 1944. Preliminary report on some mosaic diseases of iridaceous plants. Phytopathology 34:593-98.^ Steiner, G. 1945. Meadow nematodes as the cause of root destruction. Phytopathology 35:935-37. Stuart, N. W. 1943. The influence of storage temperature on forcing performance of Creole Easter lilies. Amer. Soc. Hort. Sci. Proc. 42:597. 10m-2,'47(A2063)