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Organic Allium Production

  1. 1. ATTRA Organic Allium Production A Publication of ATTRA - National Sustainable Agriculture Information Service • 1-800-346-9140 • www.attra.ncat.orgBy Katherine Adam Alliums are a cool-season crop grown in most regions of the U.S. This publication addresses commercialNCAT Agriculture culinary alliums, except garlic. A brief history of the onion is presented and some of the major variet-Specialist ies, growing regions, and types of bulbs are presented. Marketing and economic considerations of the© 2006 NCAT varieties of dehydrator and fresh bulb onions are also discussed. Production and processing issues are briefly reviewed, as are crops such as shallots and leeks. Soils, climate, and planting considerations are also discussed. Weed management and an overview of major pests and their control are also presented. Post-harvest handling and storage issues are mentioned along with a brief review of current research. References and resources follow the narrative. Contents Introduction .............. 1 Marketing and Economics .................. 3 Production Budgets ....................... 4 Other Types of Bulb Onion Crops................ 6 Are Onion Crops Alternative? ................ 8 Soil Fertility and Climate ...................... 10 Planting Systems .... 10 Irrigation ................... 11 vegetables. The dry onions fi rst brought Control of Weeds, Introduction to this country by settlers were northern Insect Pests, and Alliums are biennial monocots that are culti- European types adapted to the temperate Diseases .................... 11 vated as annuals, a cool-season crop requir- climate found throughout the Northeast. Insect Pest Management ........... 14 ing temperatures of at least 55 degrees Varieties from warmer regions of the Med- Disease Fahrenheit to emerge from seed. Optimum iterranean eventually made their way to Management ........... 15 leaf growth rates occur at temperatures of the southeastern United States. In particu- Harvest/Postharvest 68 degrees Fahrenheit to 77 degrees F. lar, varieties from Spain and Italy would Handling/Storage .. 17 Alliums include various bulbing and non- become important to the Vidalia onion Research ................... 18 bulbing species, used for both culinary and industry. The fi rst of these varieties came References ............... 18 ornamental purposes. This publication through Bermuda and were thus referred Further Resources .. 19 covers culinary alliums (except for noncom- to as Bermuda onions. mercial types), with the exception of garlic. Yellow Granex, the standard for Vidalia See the ATTRA publication Organic Garlic onions, has its origin from Early Grano.ATTRA—National Sustainable Production. For an exhaustive discussion of The variety Early Grano 502 resulted inAgriculture Information Service alliums worldwide, including ornamentals, the Texas Early Grano 951C, which becameis managed by the National Cen-ter for Appropriate Technology see Rabinovitch and Currah. (1) one of the parents for Yellow Granex hybrid.(NCAT) and is funded under agrant from the United States The other parent, YB986, was selectedDepartment of Agriculture’s History from Excel, which in turn was derived fromRural Business-Cooperative Ser-vice. Visit the NCAT Web site Onions (Allium cepa) are now thought to White Bermuda. These are short-day, sweet( have originated in southwest Asia, but a onions that formed the basis of the Vidaliahtml) for more informa-tion on our sustainable wild progenitor has yet to be found. (1) industry, beginning in 1931. Dry onionsagriculture projects. The onion is one of the oldest cultivated from northern European parentage are now
  2. 2. referred to as “American” types. Those Latest fi gures on the value of onion crops deriving from southern Europe, via the in Oregon are $74 million for 2004; Caribbean, are called “European” types. onions now rank tenth among Oregon crops. (2) Federal crop profi les have been Onions are classified as dry (bulb) or published for onion production in several green. Bulb onion varieties are generally states—including California, Colorado, classified by day-length (short, intermedi- New Mexico, Washington, Oregon, New ate, long), market use (fresh bulb, dehy-Related ATTRA York, Wisconsin, Georgia, Texas, and Ohio drator bulb, or storage type), and bulb (green onions). Some states have recentlyPublications color within the fresh market class. Sweet begun to focus on becoming onion-pro-Resource Guide to onion types are most commonly marketed ducing areas—especially sweet onions,Organic and as fresh bulbs. In general, short day-length for which there appears to be a growingSustainable onions are suitable for warm climates;Vegetable market. Wide year-to-year fluctuations in long day-length onions for those north- onion acreage in the U.S. appear in USDAProduction ern regions that grow onions. Intermedi- Economic Research Service reports goingOrganic Garlic ate length can be selected for intermedi-Production back to 1961. ( ate zones, such as Oklahoma or the CentralNCAT’s Organic Valley of California. There is some produc- The U.S. exports onions and onion prod-Crops Workbook tion of Vidalias as “green onions.” ucts to Canada, Australia, Germany, Japan,Organic Marketing The Netherlands, South Africa, Sweden,Resources There are, of course, related wild allium and the United Kingdom. India, Peru, species in North America, and these are and China are the major exporters to theSustainableManagement of still gathered. In Tahlequah, Oklahoma, U.S. Significant foreign competition fromSoil-borne Plant home of the Western Cherokee Tribe, the Peru, especially with the South Texas sweetDiseases “egg and wild onion supper” has a long onion crop, is expected in the future. ChinaThrips Management tradition in the spring. Allium cernuum exported $403 million of onions, shallots,Alternatives in the is the probable species of small, clumping garlic, and leeks in 2002—a 50 percentField onion. It should not be confused with A. increase over the preceding year. AlliumsNematodes: vineale, or “crow bait,” a very strong-fl a- are considered an area of vegetable pro-Alternative Controls vored native of Eurasia naturalized in North duction in which China will seek increasingFlame Weeding for America, that usually occurs singly. domination of U.S. and Asian markets. (3)Agronomic Crops Onions are greatly affected by weeds, According to NASS statistics, Mexico isEnergy Saving Tips insects, and diseases. One of the most the chief foreign source of green onions.for Irrigators important challenges in onion production There are strict grading standards; Mexi-Measuring and today is how to produce onion crops in can dry storage onions and onions for pro-Conserving Irrigation ways that are sustainable and environmen- cessing are allowed in if they meet the sameWater tally responsible while not losing the yields(For more achieved by use of crop-protection chemi-information, call cals as a substitute for costly hand labor.800-346-9140) (1) Many alternative strategies have already been implemented by the industry—espe- cially in New York and California, where there is some indication that insect pests are becoming resistant to insecticides. In Georgia, a 2002 trial of organically pro- duced onions met with some success. Six geographic areas have federal market orders for onions, and onions are among the top five crops raised in two other states. USDA market orders are initiated by Figure 1. Bulb Shapes – 1. flattened globe; 2. globe; 3. growers and are renewable by vote of growers high globe; 4. spindle; 5. Spanish; 6. flat; 7. thick flat; every six years. 8. Granex; 9. top.Page 2 ATTRA Organic Allium Production
  3. 3. standards of size and quality as the U.S. and Georgia short-day onions, at 11 to 12-Fresh market imports of both green and dry hour day lengths. Short-day types are theonions are more closely regulated. sweetest. The higher the pyruvic acid con- tent, the more pungent the bulb.Sweet onions grown for the fresh marketoften have a state-sponsored identity—Walla Intermediate-day fresh market bulbs grownWalla Sweets, South Georgia Vidalias, in the central California valley range fromOklahoma Candy, etc.—and must be grown seven to nine percent soluble solid contentsin the specified locality to bear the name. and 5 to 9 moles of pyruvic acid per Kg ofRegional growers search for other market- bulb. (5)ing ideas conferring “perceived value.” Long–day fresh market bulb onions range from 8 to 12 percent soluble solids and 10 toMarketing and Economics 20 moles of pyruvic acid per Kg of bulb. (5)There is usually a direct correspondence Fresh-market bulb production is not charac-between day-length sensitivity and the lati- teristic of Northern California and the infra-tude where onions are produced, with short structure is not types being produced at lower P Federal marketing orders, initiated by alatitudes. However, differences in this sen- yruvic acid group of growers for a locality, set regu-sitivity (as well as stand densities) can be is a measure lations for some commodities (currentlymanipulated to produce specialty crops including milk and some fruits and vegeta- of the sulfurlike pearl onions. Pearl onions are short- bles). Marketing orders aim to match sup- content and is usu-day types that can be grown in northern ply with potential demand at prices reflect-states (under the long days of summer) for ally dependent on ing the costs of producing and marketingearly bulbing and pearl production. the commodity by the typical well-managed soil type.Dehydrator onions include both short-day fi rms in the industry. Regulations also setand long-day varieties. Short-day vari- product standards to reflect the interestseties (Creole, Creoso, and Primero) are of consumers.selected for their high dry matter con- Currently, federal marketing orders fortent with soluble solid contents ranging onions currently exist for six U.S. geo-from 15 to 25 percent. Long-day dehy- graphic regions.drators (Southport White Globe varieties)have soluble solid contents ranging from • Vidalia Onions (GA)20 to 25 percent. (5) Production is verti- • Garlic and Onions (CA)cally integrated and the process is totally • Sweet Onions (CA)mechanized. The processer with whom the • South Texas Onionsgrower has a contract determines variet-ies and often provides seed. The Univer- • Walla Walla Sweets (WA)sity of California has published a six-page • Idaho-Eastern Oregon Onionsbulletin on growing dehydrator onions. The Georgia Department of Agriculture( ) publishes a list of recommended culti-Fresh market bulb onions have the great- vars to be grown and marketed as Vidaliaest number of varieties. Short-day types onions, but any similar cultivar that meetsare usually Grano or Granex-Grano and certain guidelines can be used by Vidaliainclude yellow, red, and white varieties. growers. Recently, however, three experi-“Imperial Sweet” and other short-day vari- mental cultivars partially derived from A.eties grown in Southern California range fistulosum in an attempt to improve shallowfrom fi ve to seven percent soluble solidcontent, 2 to 6 moles of pyruvic acid per Definition: A marketing order is a legal mechanism under which regula-Kg of bulb, and a high sugar to pyruvic tions issued by the Secretary of Agriculture are binding upon all growersacid ratio. California short-day varieties and handlers of the regulated product in a specific geographic area.begin to bulb at 12 to 15-hour day lengths, ATTRA Page 3
  4. 4. onion root systems were rejected as tend- on some Web sites are discussed below. ing to have an “off” flavor. The marketing Florida and Oklahoma budgets reflect a order regulates the shape of the Vidalia recent risk-benefit assessment of onions bulb (see Illustration, item no. 9). (4) as a potential crop, extrapolated from pro- In California there are five recognized size duction figures published in onion-produc- grades. At a packing shed or during field ing states. Costs to produce a crop in New packing, bulk trailer loads of onions cured Mexico and Wisconsin were double those in the field for three days to two weeks of some other states. are sorted. Packing grades are Colossal, University of California Vegetable Research greater than 4 inches in diameter, Jumbo, and Information Center. 3 to 4 inches, Medium, 2 to 3 inches, Repacks 1.5 to 2 inches, and Boilers, less onion.htm than 1.5 inches. Short-day onions, typically grown in the New Mexico low desert and Central Valley, are pre- Onion Cost and Return Est imates ferred by the onion ring industry (45 per-A (NM) n estimated cent of California production) because vari- _circulars/CR-603.pdf. Fixed costs 1 per- 49.4 billion eties such as Grano or Grano-Granex types cent. Variable costs double those of other pounds of typically have only a single center and states due to irrigation.frozen onions are numerous, thick fleshy rings. Harvested slightly immature, they have a high sugar Onion Production and Marketing inproduced annually New Mexico. to pyruvic acid ratio. The larger sizes arein the U.S. preferred. Fall-planted, short-day onions _circulars/CIRC577.pdf are adapted to the desert regions of South- ern California, although as transplants Mississippi they can be grown up to a maximum lati- Commercial Production of Bulb Onions tude of 36 degrees north. in Mississippi. infosheets/is1506.htm Onion production also supplies the fro- zen food industry. A USDA publication Washington estimates that 49.4 billion pounds of fro- Estimates Cost and Returns for Produc- zen onions are produced annually in the ing Onions, Columbia Basin, Washing- U.S. In addition, many of the fresh-mar- ton. ket onions, as well as high-solids dehy- onions.htm drator onions, produced in Washington state are processed after export to Pacific New York Rim countries. Crop Profi le: Onions in New York http:// Production Budgets onion.html A Michigan State Agricultural Extension Publication comments that it is “relatively Michigan easy to get into and out of onion produc- Cost of Onion Production in South- tion, as the market is often saturated.” ern Michigan. staff _Paper_2002-37.pdf. 10 p. sr599201.htm. Production budgets (except in California, Georgia where more processing is done) place fi xed Sweet Onion Production. http://pubs. costs at between 1 percent and 11 percent for onions. Production budgets found 40 p.Page 4 ATTRA Organic Allium Production
  5. 5. Two states looking at onion production Florida Alternative Opportunities for Small Farms: Bulb Onion Production [1998] • 10 percent fixed costs; 90 percent variable costs Other constraints: • severe freezes in recent years in northern Florida • very labor intensive crop, needing good management skills • need for machines—especially for planting and harvesting • curing facilities for storage do not exist • markets for fresh crop onions must be determined in advance • capital intensive crop (initial investment costs high) • potential for processing limited by lack of facilities • existing harvesters for dry onions do not work for fresh onions Oklahoma Oklahoma Candy Onion Production (three related papers) 1) Projected Net Income, Price Risk, and Yield Risk [Based on field trials with one cooperating farmer in southeast Oklahoma] • Fixed costs for Oklahoma determined to be only 5 percent, variable costs 95 percent (for southeast Oklahoma) Advantages: • National consumption of produce on the rise • Success of Texas ‘Candy’ onion (intermediate day onion, did well in trials) a knockoff on success of Georgia ‘Vidalia’ Disadvantages: • Major challenges of weed control and foliar disease • Assumption that ungraded product can be sold on fresh market within two weeks of harvest (to avoid curing, processing, handling costs of Florida study, but does not answer contention that machinery available for har- vesting dry onions cannot be used for fresh. May plan to use hand labor.) 2) Using Contracts to Reduce Marketing Risk; Applied Study of Oklahoma Onion Production A farmer-friendly summary of the research study. 3) Recent Experience with Fresh Bulb Onion Production in Oklahoma. National Allium Research Conference (2004). Had to raise their own greenhouse starts for ‘Candy’ and ‘1015-Y.’ Found that ‘Candy’ had 11 percent bolting rate (a culling rate not accounted for in previous crop budget calculations). Suggested seed supplier was to ATTRA Page 5
  6. 6. Other Types of Bulb Onion Processing Onions Crops Onions for dehydration (California) • Apaz onion – a wild relative of • Dehydrator Bulb Onion Production leek, a small bulb marketed with a (Voss) http://anrcatalog.ucdavis. short green top. “ Apaz” has been edu/pdf/7239.pdf recently promoted as an Oregon • Onion Dehydration (John W. Lund specialty crop. It is listed in the and Paul L. Lienau) http://geo- 2005 The Packer yearbook. Only a very few companies sell seed for it, and no production information has Frozen onions been published. • Production of all types of frozen • Cippolino onion – U.S. supplies onions is concentrated on the West imported from Italy. Cipol is Span- Coast, with some companies doing ish for “shallot,” but the Cippolino a broad range of operations—every- onion of commerce is a small red- thing from fresh-peeled to frozen dish true onion; A. cepa. The rings. A fledging frozen onion ring Packer suggests marketing Cippo- operation in Pecos, Texas, closed in lino onions as part of an Italian cui- 2002 when a competitor bought the sine display. operation and consolidated it with • “Boiler” onions are marketed as a an existing facility in Nebraska, specialty item. A boiler onion is sim- which had in 1985 initiated onion ply the smallest of five recognized and potato processing as a value- sizes of fresh market onions in Cali- added rural development strategy. fornia, defined as smaller than 1.5- Growers in Oswego County, New inches in diameter. The Packer York, in response to poor sales of recommends including boilers as fresh onions due to nationwide over- part of Hispanic produce displays. production in 2005, have proposed to spend $2.9 million on a frozen onion processing plant to help the local economy. Onions for seed (California) • Onion Seed Production for Cali- fornia. pdf/8008.pdf In minor onion-growing areas, onion seed is often produced by Green Onions commercial growers in a separate field away from the commercial onion crop. For various reasons, Pearl onions are produced by plant- growers prefer to produce com- i ng a shor t-day on ion i n a nor th- mercial onion crops from trans- ern latitude. They are produced in plants, rather than seed. Care must North Dakota, Minnesota, and Wash- be taken to avoid seed-borne dis- ington. An Extension bulletin by the eases. A recommended strategy is North Willamette Research and Exten- to raise seed in a field where alli- sion Center is a good source of fur- ums have never been grown before. ther informat ion. Pearl onions are Transplants are produced from the often pickled or otherwise processed. seed and then precision set in the commercial field. For details of onionprl.html seed production in California (thePage 6 ATTRA Organic Allium Production
  7. 7. number one U.S. onion producing Common home garden types such as Egyp- region), see the UC-Davis publica- tian onions and multiplier onions are NOT tion. Commercial onion seed is pro- used for commercial green onion produc- duced also in the Columbia Basin tion, but may sometimes be found in farm- region in Washington. ers’ markets in the spring. For a complete description of how commercial green onionsGreen Onions are produced, see Dept/NWREC/oniongr.html. Green onions(Scallions, Bunching Onions) imported from Mexico have come underBunching onions may be produced from increasing scrutiny in recent years becauseimmature, thickly planted white onion of outbreaks of bacterial illness traced tovarieties of Allium cepa and from Allium such imports.fistulosum (commonly known as Japa-nese bunching types), or, rarely, from aninterspecific hybrid of cepa x fi stulosum.Allium fistulosum varieties are oftenreferred to as “Welsh” onion, derivedfrom the German word “welsche,” mean-ing foreign.Green bunching onions are known by sev-eral names depending on the region ofthe country. Some of the names used are“scallions,” “green onions,” and “springonions.” All these terms can be used for Yellow Storage Onions onions, but in reality, the “green DC7060.htmlbunching onion” of commerce is mostlikely a different species from that of thebulb onion. Green onions today are most Ohio ranks seventh in the country in greenoften Allium fi stulosum, which is further onion acreage. Onion maggot is a seriousclassified into four taxonomic groups. For pest on green onions in Ohio, but a newa complete description, refer to “Alliums seed treatment with cyromazine, an insect growth regulator, shows promise. (6) Forand Allied Crops,” Vol. III by H. Rabi- more information on green onion produc-nowitch and D. Brewster. tion in Ohio, see the USDA Crop Profi leA considerable amount of Allium cepa (the bulb onion) is still used for green OHonions-green.html.onion production under certain conditionsand in certain areas. Allium cepa can be Other Extension bulletins on green onionplanted thickly and harvested immature production:for this purpose. An example is “Vida- • Green Onion Production in Califor-lia” scallions produced in Southeast Geor- nia (Voss). from Grano-Granex types. Bunching info/commodity/onion/oniongrn.pdfonions are harvested at pencil-thicknessand sold in bunches. • Commercial Green Onion Produc- tion (Georgia). http://pubs.caes.One can identify the species by looking care- at the bottom of the green leaves near About Vidalia green onion produc-where they turn white. If the leaf cross sec- tion governed by a federal market-tion is “D”-shaped (or has a flat side), it is ing order. In 2003, higher pricesA. cepa. If “O” or round, it is A. fistulosum. for Vidalias pushed the value of onion production up by more thanoniongr.html 50 ATTRA Page 7
  8. 8. • Green Bunch i ng On ions. NWREC/shallot.html. Also see the Univer- sity of Florida Extension bulletin: http:// oniongr.html • Green Bunching Onion Produc- Garden Medicinals and Culinaries is tion a source of bulbs of shallots and other hil18.html multiplier onions. • Growing Scallions (Green Onions) Leeks (A. ampeloprasum) for Market Gardeners, NF04-607. Leeks, which require a cool to moderate cli- mate and a growing season of 80 to 100 publicationD.jsp?publicationID=245 days, are a very minor specialty crop in • Crop Profi le for Onions (Green) in the U.S., as market demand is not nearly as Ohio (1999), 7 p. http://pestdata. large as in northern Europe. Commercial production centers in the Pacific Northwest OHonions-green.html Willamette Valley and Oregon Coast, where both the transplants and mature crops are Other Allium CropsS grown. Field seeding is not recommended. hallots are Transplants are often set into 3 to 4 inch Shallots (A. cepa ‘aggregatum’) affected by holes in order to produce the long white the same dis- University of Florida Extension says that stems desired in the market. The major pest U.S. commercial shallot production is on leeks is thrips. In 2004 a viral infec-eases as onions. established only in southern Louisiana, tion began to show up on garlic in Wash- but this may be a reference to the “Giant ington State. The “leek yellow stripe virus” white shallot” identified by Rabinowitch was implicated. For more information, and Kamenetsky (1) as a cross between see “the bulbous shallot and Japanese bunch- february/11388.htm. ing onion, A. fistulosum,” resulting in an amphidiploid plant that is heat-tolerant and For information on commercial leek produc- prolific with only a short dormancy period. tion, see Oregon State University Vegetable Red shallots are one of the top imports from Production Guides France. Shallot is a perennial that produces Dept/NWREC/leek.html a cluster of small, pointed bulbs from a sin- So-called “elephant garlic” (A. ampelopra- gle planted bulb. Bulbs may be of vary- sum) is actually a leek. Very large bulbs ing color, but the French Red is the only of this leek relative are marketed as a mild shallot of commercial importance. Other “garlic.” There are a number of named cul- types may be found occasionally in local tivars, as this is a popular crop in some markets and home gardens, as are vari- regions. As noted above, the “Apaz” onion ous related types of white multiplier onions. is a specific type of leek. Oregon State University notes that planting stock is difficult to obtain in large quanti- ties, but offers trial quantities of “true shal- Are Onion Crops Alternative? lot seeds” sourced from a Dutch company Onion crops cannot be considered “alter- to growers in Oregon. Either dry bulbs or native”; they are well-established, major bulbs with foliage are marketed. Shal- U.S. crops with defi nite marketing chan- lots are affected by the same diseases as nels for different types. Some states spon- onions and should not be planted where any sor research or legislate to protect a “logo” related crop has been grown before. They or name in order to gain an edge in the are also affected by harmful nematodes. market. States have even been known to Oregon State University Vegetable Pro- commercialize a “new” allium for the same duction Guides has published complete purpose. As a testament to efforts of the information on commercial production of National Onion Association and state and sha l lots, regional associations, U.S. onion consump-Page 8 ATTRA Organic Allium Production
  9. 9. tion rose from 12.2 pounds per person in in sandy, low-sulfur soils and tested for high1982 to 18 pounds per person in 2002. (7) sugar content, low pyruvic acid, and mellow flavor. Grown in the Southern Hemisphere,Surplus commercially grown onions that they fit an off-season niche for U.S. marketsdo not meet size criteria may be donated for fresh, non-storage onions. They willto food banks or other feeding programs, also keep busy the Seattle packing facilitiesalthough those with physiological defects or operated by another member of the consor-disease are usually culled soon after har- tium. The new consortium hopes to promotevest. Although imports are increasing, there sweet onions to the food service trade as ais no domestic shortfall in onion production. salad bar item. For more information seeVidalia growers in Georgia have recently the September 26 issue of The Packer andbeen told to look for export markets for up the article by Tom half of their crop. Large, perfect yel-low onions typically retail for three poundsfor a dollar. Farmers markets sell slightlysmaller sizes of whatever type they haveavailable for about a dollar a pound. Localfarmers’ markets always have a few onionsfor sale, especially in the spring. Commu-nity Supported Agriculture (CSA) organiza-tions like to provide some onions in the latefall as part of a “root vegetable share.”Contrary to marketing order specifications,smaller sizes of onions are ideal for the one-person household now so prevalent in theU.S. Once cut, a large onion will keep foronly a limited time in the refrigerator. How-ever, there is a market demand for fresh,whole peeled onions. Yellow Storage Onions in MinnesotaCornell University is a leader in innovativealternative marketing for onions and other The October 10, 2005 issue of The Packervegetable crops. Cornell University’s Smart had disturbing news for the South TexasMarketing series (http://hortmgt.aem.cornell. onion industry. “Shipments of Peruvianedu/smart_marketing) and related materials onions to the U.S. and Canada continue torecommend 1) expansion of agri-tourism, gain momentum.” Peru has ideal rich soils2) agricultural awareness programs, and in a wide range of microclimates at varying3) ag-based economic development initia- altitudes, irrigated by water from the Andes,tives as key to promoting sales of New York to produce more and more sweet onions forcommodity vegetables, including onions. fresh market. est and disease buildups are( absent, as this is largely a cool, dry, desertNYvegmarketingneeds.pdf ) area only recently put into large-scale agri-A very recent development in onion market- culture for export. Peruvian sweet onions areing is the formation of a consortium of U.S. now being actively marketed as a “high-qual-and foreign growers of sweet onions. Sweet ity sweet onion whose taste meets or exceedsClover Produce, Seattle, Washington, is a expectations year-round.” Peruvian onionsnew cooperative formed to provide year- usually rate from 3.5 to 4.5 on the pyruvicround sweet onion supplies to the food trade. scale, which measure sulfuric compounds.For eight months of the year Bland Farms’ Vidalias score 2 to 4.3, and Texas 1015s“Peruvian sweet onions” will be marketed; rate 3.7 to 4.5. The South Texas indus-the other four months Walla Walla Sweets try is most at risk for direct competitionand Vidalias. Peruvian onions are grown from Peru. Peru ideal for sweet onions; ATTRA Page 9
  10. 10. Retailers, suppliers working together. Oct. in October and November. An extended 10. p. B5. In a development that has shaken warm period following planting produces the Texas Produce Association, a large pro- a larger overwintering plant (more than duce company in the Rio Grande Valley of one-fourth-inch shank diameter), which Texas closed and was noted on p. 1 of the results in a high percentage of bolting when same issue. Starr Produce marketed South exposed to extended temperatures below 50 Texas onions. The company has converted degrees Farenheit. Some cultivars may be to a real estate development fi rm and will more prone to bolting than others. (Note the build on its agricultural land. (9) experience of Oklahoma researchers with ‘Candy,’ above.) Soil Fertility and Climate In southern states onions are likely to Onions require fertile, well-drained, non- be raised from transplants; in New York crusting soils, and are often produced in State, most are direct seeded. Short- muck soils, although sandy loams high in day Vidalia onions in Georgia are always mineral content are also favored. Heavy raised from transplants. clay soils should be avoided. A slightlyG acid pH in the 6.0–6.8 range is optimum. Short-day onions can be grown from both rowing seed and transplants; however, growing Onions require substantial amounts of onions onions directly from seed has largely been nutrients. Foliar fertilization is not rec- abandoned because of several problems. directly ommended for some parts of the country, First, onion seed is very small and requiresfrom seed has although many growers use this method adequate, even moisture during the criticallargely been aban- for applications of necessary trace ele- germination process. This is difficult to pro- ments during the growing season. Ideally, vide during the extremely hot and dry con-doned because of ditions of the September/October planting nutrients will be in place in the soil beforeseveral problems. season in South Georgia. The center-pivot the crop is planted. Soil tests should irrigation systems common to this area are be done as a guide to fertilizer applica- not designed to deliver the one-tenth inch tions. Soil pH may determine availabil- of water several times a day that may be ity of critical elements such as sulfur and required to produce a stand of onions over boron. The amount of sulfur present will an entire field. Finally, direct-seeded onions affect pungency, but some sulfur is nec- in South Georgia are more prone to bolting or developing seed stems. This is particularly essary even in producing sweet onions. true when seeded early (September and early For Vidalia and other sweet, fresh market October) and cold weather comes in the lat- onions, elements affecting fl avor must be ter part of the season, particularly in March. carefully controlled. Direct seeding onions in late October or early November to avoid seed stem develop- ment may not give the plants sufficient time Planting Systems to develop and withstand potential frost and Fall planting. Fall planting for a win- freezing temperatures. (8) ter onion crop in Georgia greatly reduces weed, insect, and disease problems, but An additional reason to use transplants is may increase incidence of physiological more uniform spacing, leading to more uni- problems due to freezing, wind, and hail formity in onion size and fewer physiologi- damage. Bolting, or seed stalk formation, cal anomalies. occurs only from fall-planted onions grown through the winter for spring harvest. The Spring planting. In Oregon’s Willamette Val- size of the overwintering plant and its expo- ley onion growers plant only in the spring, sure to cold temperatures are the most crit- though in some other onion areas both fall ical factors in determining whether or not and spring-planted onions are grown. In the plant will bolt due to a warm spell of North Dakota onions are not seeded until 45 to 50 degrees during the winter. Early April or May, since seed will not germi- plantings in late August and September are nate below 50–55 degrees Fahrenheit soil more likely to bolt than are later plantings temperature. Although harvested in latePage 10 ATTRA Organic Allium Production
  11. 11. summer, long-day onions raised in the percent of Columbia Basin onions (Washing-northern tier states are milder than south- ton) and 20 percent drip irrigation, whichern-grown summer onions, thus fi nding a some growers feel facilitates higher yieldsmarket niche. An even progression from cold and less disease pressure. With sandy soilsto warmer weather, plus careful regulation of prone to wind erosion, irrigation is some-irrigation, reduces the number of splits. times practiced to reduce soil and crop loss. Twenty percent of farmers still use a fur-Irrigation row or rill irrigation system. Irrigation isThe onion seedbed must be irrigated imme- selectively used in Wisconsin, and irrigateddiately after planting, and then as neces- onion production is increasing in New York.sary to maintain a moist condition until Onions in southern New Mexico are grownseedlings emerge. When at pencil-thick- with furrow irrigation, with some sprinklerness, onions should be transplanted and irrigation in the east and northwest. Fur-irrigated as soon as possible in the perma- row and drip irrigation are commonly usednent, slightly raised, precision-leveled “pan- in Colorado, with sprinkler irrigation usedels” in the permanent field, and every week to a lesser extent. Aas necessary after bulbing. However when For more information on sustainablyplants start to mature, they should not be ll Vida- managed irrigation, request NCAT’sirrigated. (In dry climates like New Mex- pu bl ic a t ion s, Energ y Saving Tips lia onionsico, irrigation is a significant part of direct for Ir r igators a nd Mea sur ing and grownexpense for onion production.) Irrigation is Conserving Irrigation Water. Call 800- commerciallynecessary to produce large, uniform bulbs 346-9140 to request a copy. in Georgia aredesired in the market. Because onions are irrigated.prone to physiological problems without uni- Control of Weeds, Insect Pests,form moisture in the top 12 inches of soil and Diseasesfor this shallow-rooted crop, overhead irri-gation systems are used, although they may Commercial onion crops in southern statesincrease the risk of bacterial diseases. depend heavily on spraying to control weeds, insects, and diseases. Onion diseases canAll Vidalia onions grown commercially cause severe losses by reducing yield andin Georgia are irrigated—either by center quality of marketable onions. These onionpivot, traveling guns, or permanent buried diseases can occur in seedbeds, productionpipes with overhead sprinklers. It is criti- fields, and in storage. However, diseasescal that the top 12 inches of soil be kept and other pests differ in economic impor-at a uniform moisture. Drip irrigation is tance, depending on the part of the countrynot recommended for the Georgia crop, in which onions are raised.though it is common in the Pacific North-west. Peak water demand for onions canbe as high as 1.5 to 2.0 inches per week Weed Managementduring the latter stages of bulb enlarge- Weed management is the most significantment in periods of warm weather. A half challenge in onion production. Besidesinch of water applied at transplanting (in competing for water and nutrients, weedsDecember in Georgia) helps establish good can harbor destructive insects, can serve ascontact between the soil and roots and alternate hosts of diseases, and can hamperassures a good stand. To determine ongo- hand-harvesting efficiency (in regions whereing need for water for this shallow-rooted crops are hand harvested). Weeds can seri-crop, tensiometers may be used to monitor ously reduce yields.soil moisture, at least three times per week Onions are sown at high plant densities (4in dry weather. to 6 seedlines on top of beds [panels] onlyCalifornia onion fields tend to be uniformly 40 to 42-inches wide, shoulder to shoulder)irrigated with overhead sprinklers. Cen- and not thinned in order to have the great-ter pivot sprinkler systems are used on 60 est possible yield per acre. Only ATTRA Page 11
  12. 12. Most troublesome weeds Nutsedges – CA (high desert, San Joaquin Valley), OR, GA (early fall plantings), TX, NM, NY, WI, CO Lambsquarters – CA (San Joaquin Valley, low desert (nettleleaf goosefood)), WA, OR, TX (Lower Rio Grande, Winter Garden), NM (all seasons), NY, WI, CO, Redroot pigweed (amaranth) – CA (San Joaquin Valley), WA, GA (early fall plantings), TX (all areas), NM (all seasons), NY, WI, CO Russian thistle – CA (high desert), WA, NM (winter), CO Mustards – CA (high desert), GA, TX (Lower Rio Grande, Winter Garden), NM (fall) Mallow – CA (low desert), OR, CO Purslane – CA (San Joaquin), WA, OR, TX (Lower Rio Grande, Winter Garden), NY, WI, CO Dodder – CA (San Joaquin), CO Henbit – TX (Lower Rio Grande, Winter Garden), GA Groundcherry – CA (San Joaquin), TX (Lower Rio Grande), NM (winter) Shepherd’s purse – CA (San Joaquin), GA, NY, WI Sow thistle – CA (San Joaquin), GA, TX (Lower Rio Grande, Winter Garden), NM (fall) Kochia – WA, OR, NM (winter), CO Nightshades – CA (San Joaquin), WA, TX (Lower Rio Grande), CO Spurge – OR, TX (Lower Rio Grande), NY, WI Ragweed - TX (Lower Rio Grande, Winter Garden), NY, WI, CO Morningglory – GA, NM Sunflower – TX (Lower Rio Grande), CO Spurred anoda – New Mexico, CO London rocket – CA (San Joaquin), TX (Lower Rio Grande), NM (fall) Field bindweed – TX (Lower Rio Grande), CO Annual and Perennial grasses: CA (low desert, San Joaquin), and all other states. and furrows are cultivated. Hand-weeding field bindweed, and bermudagrass, as well often does as much harm as good. (10) as clovers. Nonchemical controls are mostly employed pre-plant. (5) In an organic trial of short-day onions conducted in southeast Georgia, 2000–2001, problems Rotational crops that employ tillage can with bermudagrass and nutsedge were elimi- reduce weed levels, as tillage of standing nated by crops being winter-grown. Bermuda onion crops is not common due to risk of hay mulch provided a very satisfactory weed injury to bulbs. A method of stale seed- control rating. Yields were about half of those bed weed management that does not involve for conventionally raised onions (bags/acre), chemicals consists of several light cultiva- with most of the reduction coming in reduction tions of the field before onions are planted of size from Jumbos to Mediums. (11) to eliminate weeds germinating from the top soil layers. The most common and trouble- Onions should be planted in fields relatively some weeds are highly influenced by crop free of troublesome weeds such as nutsedge, planting time, as well.Page 12 ATTRA Organic Allium Production
  13. 13. Additional weeds, by state California San Joaquin Valley – cheeseweed. Washington Columbia Basin – groundsel, Canada thistle, ladysthumb, volunteer potatoes. Oregon Horsetail. Georgia Weeds that harbor bacterial streak and bulb rot – Cutleaf evening primrose, dandelion, pur- ple cudweed, Virginia pepperweed. Persistent weeds – sicklepod, cocklebur. Also, Texas panicum, Florida pusley, common chickweed. Texas Lower Rio Grande Valley – ironweed, barnyard daisy, croton. Plains – ironweed. Colorado Wild proso millet.In organic production, various strategies also a wide variety of weed seeds and prop-are used to minimize weed pressures. agules. Because soil solarization requiresCrop rotation, off-season tillage, and cover a summer fallow season for treatment, itcrops are used to prevent establishment fits in best with a fall-planted crop. (5) Forof weeds and weed seed dispersal. Hand more information on soil solarization, con-weeding when both the crops and the weeds tact ATTRA.are small is an option in some parts of the When used, mechanical cultivations mustcountry. Sometimes mechanical hoes may be timely and should be shallow in orderbe used. to reduce root damage. Cultivation technol-Herbicides used in conventional production ogy has advanced in recent years, and sev-should be targeted to specifically mapped eral non-traditional cultivator designs canweed populations. be found in the marketplace.Cultural Flame WeedingShallow tillage after pre-irrigation is a Flame weeding has been used on seedbeds,strategy that kills germinated weed seeds less commonly in standing crops, in cer-in the upper layer of soil and avoids bring- tain states. Biological weed controls suching up deeply buried weed seeds. For con- as weeder geese have not been found to betrol of weedy rhizomes, stolons and seed, very satisfactory and are not now used ininspect machinery when moving it from any commercial production.field to field.Another preventive measure for weed con- Onion Maggottrol is soil solarization. It is accomplished In New York state, crop rotation can be veryby applying clear plastic over a moist, clean- effective against onion maggot, but at leasttilled seed bed, for four to six weeks dur- one mile of separation is recommendeding the hottest part of the summer. Solar- between new seedings and previous cropsization kills pest insects and diseases, but or cull piles. There are no ATTRA Page 13
  14. 14. Insect Pest Management Major insect pests of onion crops, by region CA – major: onion (tobacco) thrips, onion maggot. Minor: western flower thrips, seed corn maggot, pea leafminer, army worms, bulb mites, wheat curl mites. Nematodes – Stem and bulb nematode and the root knot nematode are major onion pests in California, and stubby root nematode, minor. WA – major: onion thrips and western flower thrips, onion maggot. Minor: seed corn maggots, aphids, armyworms, cut worms, leafhoppers, leafminers, wireworms. Nematodes – Stubby root nematode a minor problem. OR – mites, cutworms, armyworms, onion maggots, thrips, leafminers, wireworms. Nematodes – Stubby root nematode a minor problem. GA – major: thrips. Minor: seed corn maggots, onion maggot, wireworm, mole cricket. Nematodes – no. TX – cutworm, wireworm. Minor: white grub, onion maggot. Nematodes – patchy occurrence of root knot nematode, onion bloat nematode, root lesion nematode, and stubby root. nematode. Problem is growing. NM – major: thrips. Minor: cutworms, cucumber beetles, onion maggots. Nematodes – Southern rootknot nematode. NY – major: onion maggot, thrips. Minor: bulb mite, cutworms. Nematodes – patchy and increasing. WI - major: onion maggot, thrips, aster leafhopper (transmits aster yellows disease). Nematodes - no. CO – major: onion thrips, western flower thrips. Minor: aphids, leafhoppers, leafminers, maggots. Nematodes - no. Some Major Onion Pests, by State: Onion Thrips Seedcorn Wireworms Cutworms Army- Leafminer Maggot Maggot worms CA X X X X X WA X X X X X X X OR X X X X X X GA X X X X TX X X X NM X X NY X X X WI X X CO X X X XPage 14 ATTRA Organic Allium Production
  15. 15. varieties with resistance. Onion maggot is however. Thrips must be controlled duringparticularly devastating in cooler growing the early bulbing stage of onions in order toareas. Excellent field sanitation is recom- minimize population buildups, as they gomended, consisting of cleaning up all cull through four life cycles a year in California.and volunteer onions out of fields before Pyrethrins, rotenone, and insecticidal soapsplanting. Fall plowing reduces the popula- are alternatives to other insecticides.tions of overwintering pupae.In the Vidalia sweet onion producing area of Disease ManagementGeorgia, insect problems during the winter Economically significant diseases,growing season are not as severe as in areas by state:that produce onions in spring, summer, orfall. Onion maggot and seedcorn maggot CA – major: bacterial soft rots, basal rot,are customarily controlled through a pre- black mold, blue mold, botrytis leafspot,plant application of an appropriate insecti- downy mildew, botrytis bulb rot, pink root,cide, either just before seeding plantbeds or purple blotch, stemphylium leafblight, sourjust prior to transplanting. An alternative skin, white rot, and to use a long rotation, avoiding corn just WA - major: Botrytis neck rot, Aspergil-before planting onions. In California grow- lus black mold, pink root, bacterial soft rot,ers avoid planting onions in fields high in and Fusarium basal rot. Minor: Dampingorganic matter and practice good field san- off, downy mildew, onion smut, white rot,itation. Natural enemies of onion maggot Iris yellow spot virus (new).and seed corn maggot include lady bugs,beetles, birds, parasitic wasps, nematodes, OR – major: rots, molds, blight, mildew,and parasitic fungi. Release of sterile onion rust, blotch, smut, and pink root.maggot fl ies is being researched. Diatoma- GA – major: pink root, Botrytis neck rot,ceous earth is another nonchemical control Botrytis leaf blight, purple blotch, centersometimes used. rot, sour skin, bacterial soft rot. Minor: Downy mildew (rare), bacterial streak andThrips bulb rot (due to excessive fertilization,Fields should be carefully scouted for pres- excessive rain).ence of either of the two species of thrips TX – major: Botrytis leaf blight (100 per-that commonly attack onion foliage, leaving cent acres), Downy mildew (100 percentit more susceptible to disease. This scouting acres), Purple blotch (8 percent acres).is done in late winter or spring for south- Minor: pink root – variable, but increasingern growers. In California thrips are one in frequency and severity.of the two most significant insect pests ofonions. Growing resistance to insecticides NM – pinkroot, fusarium basal rot, botrytisis suspected, although not documented. bulb rot, black mold, purple blotch, bacte-Cultural controls include planting a thrips- rial soft rots.resistant cultivar such as Grano or Sweet NY – Damping off, smut, botrytis leafSpanish and growing onions during the blight, purple blotch, Stemphylium leafrainy season; both rainfall and overhead blight and stalk rot, downy mildew, bac-irrigation suppress thrips. Growers also terial soft rot, slippery skin, and sourmake new plantings upwind of older plant- skin, fusarium basal rot, pink root, botrytisings and sometimes plant in proximity to neck rot.carrots. Biological controls with beneficialorganisms include pink lady beetles, green WI – Botrytis leaf blight, botrytis neck rot, downy mildew, fusarium basal rot, onionlacewing larvae, minute pirate bugs, preda- smut, pink root, purple blotch.tory mites, lady bugs, and an insect-specificfungus (Beauveria bassiana). None of these CO – Botrytis leaf blight, botrytis neck rot,methods will provide complete control, downy mildew, pink root, purple ATTRA Page 15
  16. 16. Fungicides are commonly applied for con- enhance disease development. Growing trol, but recommended cultural controls for onions in a soil temperature range below fungal diseases include the following: 75 degrees Farenheit will also inhibit pink root losses. If a fixed irrigation system is in • Plant resistant cultivars place, this limits options for crop rotations • Use crop rotations and other alternatives, especially if there is • Protect plants from injury (by limited acreage. Solarization of the soil is insects, fertilizers, and machinery) used in California’s San Joaquin Valley to prevent pinkroot. • Store bulbs at proper temperature/ humidity with adequate ventilation Botrytis leaf spot is a particular problem • Promptly and adequately dry bulbs in onion seed fields. Seed fields in Cali- after harvest fornia should be on a three-year rotation away from onions. • Get rid of cull piles and debris (prac- tice good field sanitation) Nematodes • Avoid extended overhead irrigation; Stem and bulb nematode and the rootN ematodes reduce hours of leaf wetness knot nematode are major onion pests in are con- • Allow tops to mature before harvest California, with stubby root nematode trolled by • Avoid planting in poorly-drained soil causing some damage. Nematodes are controlled by sanitizing equipment andsanitizing equip- • Eradicate unwanted plants preventing the movement of infested soilment and prevent- • Use appropriate levels of nitrogen to uninfested areas, in addition to plant-ing the movement fertilizer and irrigation ing onions in well-drained soil. Plant-of infested soil to • Plant only disease-free material in ing when soil temperatures are belowuninfested areas, in disease-free soil 64 degrees Farenheit minimizes nema-addition to plant- tode damage (especially from root knot • Wash equipment after use nematodes). Growing nonhost crops suching onions in well- • Remove infected plants and soil when as carrots and lettuce for several yearsdrained soil. practical helps decrease stem and bulb nematode Pink root is the most common and damag- populations. Myrothecium verrucaria, ing bacterial disease in onions grown in botanical extracts, pathogenic fungus, Georgia. It is greatly enhanced by stresses and diatomaceous earth are biologically imposed on plants such as heat, cold, derived nematacides used in addition to drought, flooding, and nutrient toxicities/ cultural controls. deficiencies. The fungus reproduces and In Washington the most important nema- survives indefinitely in soil; therefore, con- tode pest of onions is the stubby-root nem- tinuous production of onions in the same atode, a particular problem in very sandy field results in increasing losses to pink soils with grasses or cereals in the crop root, which kills plants outright or renders rotation. However, crop rotation is the pri- the onions unmarketable. mary cultural control method. In Oregon Disease management requires a systems stubby-root nematode overwinters in soil approach that involves practices such as and causes the most problems during cool, rotation, sanitation, optimum fertilization, damp springs. Cultural controls such as crop rotation are used in addition to pre- preventive fungicide/bactericide applica- plant field fumigation. In both states, onion tions, harvest timing, and proper handling. growers are cautioned against planting For pink root, using a long rotation to non- immediately after a mint crop. related crops (three to seven years) is the key management strategy to reduce losses. In New Mexico heavy infestations of the In addition, optimum soil tilth, fertility and southern root-knot nematode that inhibits water management will reduce stresses that onion growth and bulb development in bothPage 16 ATTRA Organic Allium Production
  17. 17. spring- and fall-planted onions are con- Harvest/Postharvesttrolled chemically. (Nematode infection isoften mistaken for salinity injury because of Handling/Storagesimilarities in above-ground symptoms.) Optimal conditions for managing all aspects of post-harvest handling and stor-Nematodes are not a problem in Colorado age have been well studied. An excellentonion-growing areas, and in Texas, nem- in-depth treatment is Chapter 10, Onionatodes are only a minor pest at present. pre- and postharvest considerations byOccurrence is variable among fields within I.RD H.S. MacTavish in Allium Crop Sci-a region, but increasing in frequency and ence: Recent Advances. (1).severity. Low soil temperatures in winterlimit nematode activity and reproduction California onions are harvested at aand mature females are immobile, but eggs slightly less mature stage for fresh pro-can be rapidly spread by running water, duce than for storage. Determining whenequipment, transplants, sets, and bulbs. to harvest is an art born of experience, rather than an exact science, and is some-Nematodes have not been an economic times influenced by marketing opportu-problem in New York, Georgia, or Wiscon- nities. The amount of tops fallen over issin, but are now increasing in frequency not a precise indicator of maturity, and Yield. A 1980 trial ofand severity in certain fields and in cer- experts differ about this indicator. Irri- yellow Granex oniontain regions, delaying onion maturity and gation management is key. Stopping irri- at Beaumont, MS, yielded 14,500 poundsreducing yields. Severe, but patchy, damage gation too soon will reduce yield. Irrigat- per acre (290 50-is especially apparent during dry periods. ing too late, or applying too much water pound bags) of onionsNematodes found in New York are the root late in the season can lead to splitting or that were two orknot, onion bloat, root lesion, and stubby disease problems. more inches in diam-root. The main controls are cultural: rotate eter (Repack size andwith nonhost crops (principally grain crops) In California, before hand harvesting, tops above).for two years; use antagonistic crops such are rolled to enhance maturity. On a pre-as sudangrass and rapeseed, and avoid cision-leveled field, onions are undercutintroducing nematodes to clean fields on using a hand-operated rod weeder, theninfected bulbs or infested soil on equipment. picked up by hand. However, in somePre-plant soil fumigants are also used. regions, a modified potato lifter is used for the cutting and picking up. Harvest-Wind/Physiological damage ing must start immediately after cutting in Southern California to avoid sunburn.Physiological problems in Georgia winter Onions were formerly field cured in bur-onions are often induced by weather. Freez- lap sacks for three days to two weeks prioring promotes translucent scale, and lesions to grading and packing, to allow the bulbscan be due to physical damage from wind to dry and form a protective outer cover-or hail. Greening and sunscale can occur. ing. A preferred method is to move onionsStriping is often due to sulfur deficiency, or into special storage areas immediatelycan be due to a mutation. (4) after lifting and air-dry them in preciselyOnions raised in New York state are pro- regulated temperatures up to 20 days.tected from wind damage at the seed- (1) In addition to size standards, bulbsling stage by barley windbreaks planted are graded for quality to eliminate imma-at the same time as onion seeding. Once ture, decayed, sunburned, and mechani-the onions are established, windbreaks cally injured bulbs, doubles, and bulbsare killed with a selective herbicide (or that have started to sprout. The exceptionthey could be hand weeded or mowed for to use of hand labor is contract onions fororganic production). Wind damage can be dehydration, where the whole process issignificant, and total crop loss due to winds entirely mechanized. The standard con-in May or early June is not rare, according tainer for graded onions is a 50-poundto Cornell Cooperative Extension. cardboard box or mesh ATTRA Page 17
  18. 18. Shelf life of fresh market onions harvested least some bearing on onion production. before maturity is only 4 to 6 weeks. Fully Most ongoing research and development of mature bulbs (either fresh market or dry new varieties is carried on by seed compa- onions) can be stored up to six months at nies, not public institutions. optimal storage temperature and relative In 2002–2003 the University of Georgia humidity (33 degrees Farenheit, 60 to 70 percent humidity). Air movement between studied the potential for organic onion pro- storage containers is essential. Onions that duction in Georgia (see above). In 1997, are incompletely cured or improperly han- a farmer/rancher SARE grant was awarded dled in storage are susceptible to many in support of an organic onion production kinds of post-harvest mold, which can be project in a North Central state (specifically, initiated by exposure to light rain or dew control of onion maggot). In 2002 a West- while field curing. ern SARE research and education proj- ect investigated the use of straw mulch to enhance predators in control of onion thrips Research in dry bulb production. In 2001 a North- Research is ongoing in Georgia to develop east farmer/rancher project used hardwood a cultivar resistant to pink root and at an ramial woodchips (small branches and experiment station in Oklahoma in support twigs) as mulch to control weeds. Biofumi- of an Oklahoma sweet onion industry, and gants, field waste disposal, and cover crop- at New Mexico State University in support ping were also investigated for onions. of New Mexico’s fledgling onion industry. California has called for more research on In December 2004 a national conference the role of natural enemies in onion pro- on allium research was held at Colorado duction, particularly for control of thrips. State University. For more information, Some Sustainable Agriculture Research see and Education (SARE) projects have at Allium/schedule.html.References 6. Staff. 2004. Research peels back onion maggot resistance puzzle. Ag Answers. March 9. p.1. Rabinowitch, H.D., and L. Currah. 2002. Allium 1. Crop Science: Recent Advances. CABI Pub- AgAnswers/story.asp?storyID=3606 lishing, New York, NY. p. 21–22.2. Staff. 2005. Value of Oregon agriculture tops $4 7. Staff. 2003. 90 years of blood, sweat and onions. billion mark. The Agriculture Quarterly. Onion World. July–August. p. 2. Oregon Department of Agriculture, Salem, OR. p. 5. onionworld/julyaug2003.htm3. Lance Jungmeyer (The Packer). 2005. China 8. Boyhan, George, Darbie Granberry, Terry Kelley, presents opportunity, poses threat. Florida and Reid L. Torrance. 2001. Transplant pro- Farmers. Oct. 3. 1 p. duction. p. 4. In: Boyhan, George, Darbie news/articles/china.htm Granberry, and Terry Kelley (ed.) Onion Pro-4. Boyhan, George, Darbie Granberry, Terry Kelley duction Guide. Cooperative Extension Ser- (ed.). 2001. Onion Production Guide. Coop- vice, University of Georgia, Tifton, GA. erative Extension Service, University of Geor- gia, Tifton, GA. 40 p. http://pubs.caes.uga. B1198.htm edu/caespubs/pubcd/B1198.htm 9. Offner, Jim. 2005. Texas’ Starr Produce Closes5. Staff. 1999. Crop Profi le for Onions in California. Shop. October 10. p. 1A. NSF Center for Integrated Pest Management, North Carolina State University. p. 2. 10. Elmore, C., and D. Donaldson. University of California. 1998. Weeds: Integrated Weed caonions.html Management. IPM Pest Management Guide-Page 18 ATTRA Organic Allium Production
  19. 19. lines—Onion/Garlic. University of California Onion Arthropod Pest Management Division of Agriculture and Natural Resources, Oakland, CA. p. D1. Onion Links11. Boyhan, George E., and C. Randy Hill. 2002. Producing Organic Vidalia Onions. p. 22–23. In: William T. Kelley (ed.). 2002. Proceed- Bulb Onion Production in Eastern North Carolina ings of the Georgia Vegetable Conference. (1997) University of Georgia, Tifton, GA. Oregon State Commercial Vegetable Production Guides—Onions (5 pubs) GFVGA2002.pdf Resources Onions (TX) vegetables/onionsCrop profiles Agricultural Alternatives: Onion Production (PennCrop Profi le for Onions in Colorado (2003). 30 p. State) oniononions.pdfCrop Profi le for Onions in Georgia. 6 p. History of the Sweet Texas Profi le for Onions in New Mexico (2000). 6 p. publications/onions/onionhis/html Yellow Storage Onions (MN) Profi le: Onions in New York (1999). 26 p. DC7060.html Onions in WisconsinCrop Profi le for Onions in Oregon. 6 p. Vegetable Production Guide for CommercialCrop Profi le for Onions in Texas (2003). 12 p. Growers Onions Profi le for Onions in Washington. 20 p. Onion Production in Saskatchewan Profi le for Onions in Wisconsin (1999). 22 p. Agricultural Alternatives (Penn State University) http://agalternatives.aers.psu.eduWeb sites • Organic Vegetable ProductionUC IPM Online: Statewide Integrated Pest Manage- • Onion Productionment Program (2005). Onions (2004). Onion World. Published by the National Onion Asso- Note: Supersedes publication UC IPM Pest ciation Guidelines (1990)North Dakota State University Extension SARE Research www.sare.orgUniversity of Georgia. 40 p. SW02-017 (2002) – Saito, Reid, and Clint Shock. The Use of Straw Mulch to Enhance Predator Popula-Western Dry Bulb Storage Onions. tions Along with Biopesticides to Control Onion Thrips in Dry Bulb ATTRA Page 19
  20. 20. FNC04-497 (2004) – Determination of an Economi- Proceedingscally Optimal Organic Control of Onion Maggots in Kelley, William Terry (ed.). 2004. Proceedings:Allium Crops. Final Report. 2004 Southeastern Regional Vegetable Conference.ONE04-027 – Integrating Compost into an Inten- Savannah, GA. (Abstracts)sive Plasticulture Production System for Vegetables. • East Georgia Extension Center, Statesboro.Abstract. Foreword. p. xvii, 1, 2.FNE01-387 – Using Hardwood Ramial Woodchips as • Boyhan, George E., C. Randy Hill, and Raya Time-Saving Mulch for Weed Control Final Report. Hicks. Potential for Organic Onion Production. p. 8–9.LNE01-154 – Farm Ecosystem & Management FactorsContributing to pest Suppression on Organic & Coven- • Johnson, Wiley C., III. Weed control withtion Farms—Phase II. Final Report. organic production. p. 6–7.SW01-023 – Biofumigants in Commercial Onion Pro- • Paulk, Joel Thad. Effects of CO2 on Storedduction to Enhance Soil Nutrient Availability, Soil Onions. p. 63.Quality, and Control of Weed, Neamatode, and Dis- • Seebold, Kenneth W., Jr. Soilborne Diseasesease Pests. Annual Reports. of Onion in Georgia and Their Management. p. 64–67.FW00-012 – Residue Management in Furrow Irri-gated Reduced Tillage Systems. Final Report. • Uva, Wen-fei. Strategies for selling at the com- petitive Produce Market. p. 22–24.LNE97-094 – Ethnic Markets and Sustainable Agri-culture. Annual. PublicationsLS97-087 – An Integrated Vegetable Production, Schwartz, Howard F., and Michael E. Bartolo. 1995.Postharvest and Marketing System. Final Report. Colorado Onion Production and Integrated Pest Man- agement. Colorado State University, Fort Collins, Col-SW97-045 – Decomposition and Nutrient Release orado. 40 p.Dynamics of Cover Crop Materials. Final Report. Schwartz, Howard F., and S. Krishna Mohan. 1995.FS95-033 – Cover Crops in Integrated Vegetable Pro- Compendium of Onion and Garlic Diseases. Ameri-duction Systems. Annual. can Phytopathological Society (APS) Press, St. Paul,AS93-007 – Evaluation of Recycled Paper Mulch as MN. 54 Alternative to Black Plastic Mulch in Vegetable Lucier, Gary, and Biing-Hwan Lin, and Jane Alls-Horticulture. Final Report. house, 2001. Factors affecting onion consumption inSW01-057 – Transition to Organic Vegetable Produc- the United States. Vegetables and Specialties Situa-tion by Large-Scale Conventional Farmers tion and Outlook. p. 28. Organic Allium Production By Katherine Adam NCAT Agriculture Specialist © 2006 NCAT Paul Driscoll, Editor Tiffany Nitschke, Production This publication is available on the Web at: or IP 138 Slot 143 Version 091306Page 20 ATTRA