Jonathon Smith Burt Bluhm Department of Plant Pathology University of Arkansas Division of Agriculture Zearalenone (e.g., DON) Aflatoxins O O OH CH 3

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1 N 2 C 3 C 3 6/5/2014 Jonathon Smith Burt Bluhm Department of Plant Pathology University of Arkansas Division of Agriculture Fumonisins Zearalenone Trichothecenes (e.g., DN) Aflatoxins chratoxins Ergots What are mycotoxins and why do they exist? Which commodities are affected most often in Arkansas? What conditions lead to mycotoxins? ow are mycotoxins influenced by grain storage? What new technologies are being developed for management? Leukoencephalomalacia Why do mycotoxins exist? Feed refusal Dermal toxicity umans: esophageal cancer, nephropathy, neural tube defects 1

2 Periodically/persistently Less frequently Corn Wheat Rice Sorghum (Milo) Cotton Soybean Grain storage issues = opportunity for mycotoxin development Aspergillus flavus and Aflatoxin Ustilaginoidea virens and Ustiloxin 3 C 3 C N N 2 N N C 3 S 3 C N 3 C 1998 Aflatoxin outbreak cost Arkansas growers > $15,000, Wide spread aflatoxin -- 3 to ppb Prolonged heat & drought Some fields mowed down Many loads rejected Present but not widespread Relatively few reports Fusarium verticillioides and Fumonisin N 2 C 3 C 3 2

3 Fusarium graminearum: Deoxynivalenol and Zearalenone ybrid or Cultivar Selection Goal: Prevent and/or avoid mycotoxins Plant ealth arvest Pre-harvest Decisions Storage Goal: Maintain existing grain quality Penicillium spp. and chratoxin Fungi become associated with grain in the field Fungi hibernate but don t die during storage In storage, fungi will grow if conditions are favorable Moisture Temperature Clean grain can become contaminated quickly Pre-harvest Post-harvest Lower quality grain = greater risk of mycotoxin development in storage Damage during growing season, harvest & storage increases risk Diseases, insects, environmental stress Moisture content at harvest too wet or too dry Combine cylinder speed General grain handling during bin loading Aggressive drying Turning/blending grain Plant health Damage (insect or otherwise) Plant stress Environmental conditions. Cropping system Wrong hybrid/cultivar for AR Length of time in field past maturity Drying Storage Processing Grain quality cannot be improved post-harvest Temperature and moisture are the key problems Iowa State University Extension 3

4 Seasonal temperature changes cause moisture migration in bins Concentration of moisture in hot spots can lead to crusting Fungal growth is often associated with crusting Aerate grain for temperature control will also control moisture Fungal growth is halted at 13% moisture Segregate low-quality grain if possible Maintain good bin hygiene Dry grain appropriately Control temperature/moisture through aeration Monitor bins Fall moisture migration Spring moisture migration Clean grain can catch mycotoxin-producing fungi from dirty bins Climate Limited management options Can cross-contaminate betweens crops (e.g., corn to rice) Bin sanitation is crucial, especially after known issues Genetic resistance is unavailable Need for more research Conventional Check periodically Look for condensation in bin Evaluate grain temperature Visually check for crusting/slimy grain Check grain for odor Probe to locate clumping Technology-Driven Computer-based systems have been developed to monitor bins Thermocouples on cables provide a 3-D assessment of grain Refining Pre-harvest Management Practices Developing Next-Generation Bio-control Products Creating Transgenic Resistance to Mycotoxins Assessing mycotoxin potential in Arkansas crops Developing new strategies for Post-harvest control From: Tri-States Grain Conditioning 4

5 Little known about what fungi are most commonly associated with rice in Arkansas New 2014 Project: Prevention of mycotoxin development and quality degradation in rice during on-farm, in-bin drying and storage Led by Dr. Griffiths Atungulu, Dr. Terry Siebenmorgen, & Dr. Samy Sadaka Contact Information Burt Bluhm Department of Plant Pathology U of A Division of Agriculture Fayetteville, AR Ph bbluhm@uark.edu 5