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Disease and Insect Management in Organic Small Grains

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Disease and Insect Management in Organic Small Grains A project of the National Center for Appropriate Technology 1-800-346-9140 • www.attra.ncat.org Disease and Insect Management in Organic Small Grains Susan Tallman, CCA NCAT Agronomist Introduction Published April 2011 Managing the complex bio- © NCAT logical system of an organic IP388 small grain farm can be a challenge, particularly in terms of disease and insect Contents management. Introduction ......................1 Because synthetic fungi- Disease Management ....1 cides and insecticides are Specifc Grain generally not allowed in Diseases ..............................3 an organic system, preven- In-crop Insects ..................9 tion is the main strategy Stored-grain Insects .....11 for avoiding pest problems. Conclusion ...................... 14 Organic winter wheat at the Quinn Farm, Big Sandy, MT. Photo: Susan Tallman, Successful prevention usu- NCAT ally involves many diferent Te third tier of the hierarchy is the use of bio- strategies in combination, rather than relying on logical or allowed synthetic substances for the a single one. control of pests. Tese methods are allowed only Te purpose of this publication is to outline var- (and are most efective) when the foundational ious strategies that make up a good organic dis- practices in the first and second tiers are in ease and insect management plan, as well as to place. Tese third-tier measures are for use once describe some specifc diseases and insects that a disease or pest is present, after the frst levels afect small grain crops. Although this publica- of prevention strategies have failed. Understand- tion pertains to various regions of the country, ing foundational biological principles, rather than the main focus is on the Plains states—where simply substituting organic inputs for conven- most organic small grains are grown. tional ones, is a key to good organic management. The National Organic Disease Management Program Standards Climate and Location Te National Organic Program Regulations sec- Two important determining factors for disease tion § 205.206 specifes the crop pest, weed, and development are climate and location. Areas disease management practice standard as a hier- with low humidity generally have much less dis- The National Sustainable archy of practices (NOP, 2010). Te foundation Agriculture Information Service, ease pressure than areas with high humidity, ATTRA (www.attra.ncat.org), of any organic pest-management strategy is crop was developed and is managed since it usually takes six to 12 hours of continual by the National Center for rotation, sanitation, and cultural practices such leaf wetness for a fungal leaf disease to develop Appropriate Technology (NCAT). as variety selection. The project is funded through (Burrows, 2009). Tis probably explains why a cooperative agreement with the United States Department Te second tier in the hierarchy is mechanical the Great Plains states are the top organic-grain- of Agriculture’s Rural Business- producing states in the nation. If you live in a Cooperative Service. Visit the and physical methods that may include intro- NCAT website (www.ncat.org/ duction of natural predators, natural traps, and region of the United States with high humidity sarc_current.php) for more information on repellents, and development of habitat for natu- and heavy disease pressure, you need to consider our other sustainable ral enemies. carefully whether organic small-grain produc- agriculture and energy projects. tion is right for you. Figure 1. Organic Crop year. Regular use of Certifed seed will help man- Disease Management age seed-borne diseases such as smut and bunt. Practice Standard. Level 3 § 205.206 (e) Certifed Seed Biological sub- stance, or synthetic The term “Certifed seed” does not refer to certi- included on the National List; must be documented fed organic. Rather, it denotes seed that is pro- on Organic System Plan. duced under conditions that assure its purity and vigor. “Certifed seed is produced from founda- tion, registered, certifed, or other approved seed § 205.206 (d) stocks. This seed is two generations from founda- Management practices which suppress Level 2 the spread of disease organisms; or tion seed. Certifed seed cannot be used to pro- application of nonsynthetic biological, duce Certifed seed again without the approval botanical, or mineral inputs. of the state certifcation agency, which can approve production only under extreme condi- tions” (Ulmer and Stuber, 1997). Double-certifed seed is seed that is considered § 205.206 (a) Level 1 Crop Rotation both Certifed (from Foundation seed) and cer- Sanitation tifed organic. Currently, the chance of locat- Cultural Practices ing double-certifed seed is very slim (Zwinger, 2009). However, the Organic Seed Alliance con- tinues to work toward increasing the quality and amount of organic seed used in feld crop pro- Cultural Practices duction. Their website is www.seedalliance.org. There are several cultural practices to help prevent diseases, including variety selection, Further Resources delayed planting, and irrigation timing. Selecting Quality Seed of Cereal Grains. 1990. NDSU Extension circular, A-500. J.L. Helm and L.A. Resistant Varieties Spilde. Te frst step in disease management is selecting www.ag.ndsu.edu/pubs/plantsci/smgrains/a500w. a variety with disease resistance. Choose variet- htm ies that are specifc to your area and that have been bred with resistance to local diseases. For example, stem rust is a common grain disease Rotation that can be managed by good variety selection. Rotation is another tool for disease management. State Extension stations conduct annual variety Fungal diseases such as tan spot and Septoria trials that list the resistance levels of diferent survive on stalk residue. Fusarium head blight is varieties. Check their annual reports for recom- also carried in the residue of wheat, barley, and mendations. corn. Moving to a legume or oilseed in rota- tion will help break this disease cycle. (For more While resistant varieties provide the frst line of information on designing an organic small grains defense, there is no one variety of grain that is crop rotation, consult the ATTRA publication resistant to every disease. Prioritize your selec- Organic Small Grain Production Overview.) tion of resistant varieties by the diseases most common in your area. Delayed Planting Planting when soil temperatures are warmer can Seed Quality help manage soil-borne fungi such as Pythium Find the plumpest, highest-germinating seed and Rhizoctonia. Typically, these fungi are more possible, and plant in high density to account of a problem in larger-seeded crops such as gar- for any loss of stand due to damping of. When banzo beans and corn. However, if you have had possible, select Certifed seed from a reputable problems with these diseases in the past, try delay- dealer. Make sure the seed is a pure variety, and ing your spring planting until soil temperatures that you know what you are buying. In general, are warm enough to allow optimal seed germi- Certifed seed should be purchased every third nation and plant establishment (Burrows, 2009). Page 2 Disease and Insect Management in Organic Small Grains Irrigation Timing content exceeds 12%. If there is concern about the grain’s moisture content, use aeration in the If you are growing grains using irrigation, do bin to dry the grain. High moisture levels and not irrigate during the fowering stage. Flower- elevated bin temperatures lead to mold, grain ing is the susceptible period for Fusarium head deterioration, and insect infestation. blight and ergot. If you are able to control tim- ing of water application, do not water during Further Resources this period. Grain Moisture Content Efects and Man- agement. NDSU Extension publication AE-905 Crop Scouting (Revised). 1995. Dr. Kenneth J. Hellevang, PE, Crop scouting is an essential part of disease Extension Agricultural Engineer. www.ag.ndsu. management. Te earlier you can detect dis- edu/pubs/plantsci/crops/ae905w.htm eases in the feld, the more time you have to Energy-Efcient Grain Drying Resources. respond. Hone your skills in disease diagnosis. ATTRA. www.attra.ncat.org/attra-pub/graindrying. Local Extension agents often have identifcation html guides available in print and online versions. Buckwheat Harvesting, Drying, and Storage. Likewise, most land-grant universities have Dr. Bill Wilcke. www.nysaes.cornell.edu/hort/ Extension pathologists on staf and diagnostic faculty/bjorkman/buck/guide/dry.html labs where growers can send any questionable plants for diagnosis. Using Farm Moisture Testers. Iowa State Exten- sion, PM-1633. 1995. Charles Hurburgh. www. If you discover a disease in your felds, there are extension.iastate.edu/Publications/PM1633.pdf several options. If the disease is not a serious problem for further infestation, or harmful for Specifc Grain Diseases human or animal consumption, you may choose simply to live with the reduced yield. Another Special thanks to Dr. Mary Burrows and Dr. Bill alternative is application of biological or allowed Grey of Montana State University for providing synthetic substances. Check the ATTRA Biora- information on specifc grain diseases and their tionals: Ecological Pest Management Database management. (www.attra.ncat.org/attra-pub/biorationals/) for In addition to general cultural practices, there allowed organic substances for specifc diseases. are some specifc diseases of which organic small Extreme cases may require terminating the grain growers should be aware.
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