November 9, 2009
CORN EAR ROTS AND MYCOTOXINS
This isn’t a year when Aspergillus (and aflatoxin) would be expected to be found much, but there are other ear rots showing up and some of them can produce mycotoxins. Cladosporium (dark green to grayish black mold that can cause black streaks on kernels) and Trichoderma (dark green mold with a fuzzy appearance) are two that are being reported. Fortunately neither of these often produce mycotoxins. Fusarium / gibberella and Diplodia are also being found. These are pink and white molds. Fusarium and gibberella are different life stages of the same fungus and can cause Deoxynivalenol (DON or Vomitoxin), Fumonisin, and Zearalenone. These toxins are also heat stable.
Grain from fields with obvious mold problems should be tested for mycotoxins even if the molds are not white or pink because the darker molds may be masking the presence of fusarium / gibberella. Grain samples can be sent to the ISU Diagnostic Vet Lab, or samples can be sent in by a local vet. A sample submission form is available at http://vetmed.iastate.edu/sites/default/files/vdl/forms/MycotoxinForm.pdf. If you screen for all 4 of the main mycotoxins, the fee is $70. This just determines whether the toxins are present or not. To determine the level of contamination, another screen needs to be done (about $35). This will determine whether the grain can still be fed even though there is some contamination. For information on how to sample the corn and on safe levels of mycotoxins see http://vetmed.iastate.edu/sites/default/files/vdl/MycotoxinInfo.pdf. For the latest information on corn ear rots being found see: http://www.extension.iastate.edu/CropNews/2009/1030robertsonmunkvold.htm. In this article are links to several earlier articles on ear rots and mycotoxins.
Soybean harvest is finally starting to wind down with the dry recent string of dry days. However, reports of high moisture soybeans continue. The good news is that you are better off selling soybeans at 14% moisture than at 10% moisture. Some grain elevators are not accepting beans that have greater than 14-15% moisture. Air drying would be the best alternative for beans that are too wet to sell, but of course this takes more time than drying with heat. It is very easy to over-dry soybeans with heat. Charley Hurburgh has a nice article answering many of this fall’s harvest and storage questions (including drying soybeans) at http://www.extension.iastate.edu/CropNews/2009/1030hurburgh.htm.
FOR YOUR CALENDAR
Integrated Crop Management Conference – Ames
Choose from over 40 workshops featuring the latest crop production information from experts around the Midwest. The 2008 conference sold out early with over 900 attending. Registration information is available at http://www.aep.iastate.edu/icm/homepage.html.
Ag Chemical Dealer Update – Iowa City
The Ag Chemical Dealer Updates deliver the latest crop production recommendations, news and information directly from Iowa State University Extension. Each location features updates on weed, insect, crop disease and soil nutrient management brought to you by ISU experts. Meetings help prepare seed, chemical, and fertilizer dealers, crop consultants, farm managers and agronomists for the challenges of the upcoming crop production year. CCA credits available. Each meeting includes continuing instructional credits for Commercial Pesticide Applicator recertification in categories 1A (weeds), 1B (insects), 1C (diseases), and 10 (research and demonstration) for 2009. Registration information for all Ag Chem Dealer Updates, including the Waterloo location, is posted at http://www.aep.iastate.edu/acu/homepage.html.
Crop Advantage Series – Burlington
Elwynn Taylor will again be a featured speaker, providing us with insights and things to watch as we approach the 2010 crop year. Choose from many workshops on pest management, soil fertility, crop production and marketing. CCA credits will be available. Private Pesticide Applicators will be able to complete the requirement for their Continuing Instruction Course. More detailed information will soon be posted at http://www.aep.iastate.edu/acu/homepage.html.
Crop Advantage Series – Cedar Rapids
Craig Johnson, long time meteorologist, will be one of the featured speakers at this year’s conference discussing “Global Warming or Global Cooling?” Choose from many workshops on pest management, soil fertility, crop production and marketing. CCA credits will be available. Private Pesticide Applicators will be able to complete the requirement for their Continuing Instruction Course. More detailed information will soon be posted at http://www.aep.iastate.edu/acu/homepage.html.
If you have any questions, please feel free to contact the Iowa State University Extension Office.
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