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Northern Illinois Agriculture

University of Illinois Extension

Another trip to campus

Posted by Russel Higgins - Corn

After spending most of the summer at the NIARC, it seems that I am catching up on my traveling. Today the Extension marketing committee started planning for the upcoming 100th anniversary of Extension. It will be exciting to revisit early successes and the unlimited future for Land Grant Colleges and Extension!
While in Turner hall I had the chance to visit with Dr. Carl Bradley. Carl shared that as harvest picks up in southern Illinois he has been receiving a number of calls concerning aflatoxins. He also stated that the aflatoxins are being found in areas that were not necessarily the most stressed. For producers who plan on binning some of their 2012 corn crop, it would behoove you to check the corn BEFORE you harvest and bin the crop. (very important from a crop insurance perspective!)

The following is a is a reprint from Dr. Bradley's August 10th Bulletin article

With high temperatures and dry conditions being prevalent during this season's corn grain-fill period, the risk of Aspergillus ear rot is high. Caused by the fungus Aspergillus flavus, Aspergillus ear rot is observed as a yellowish-green mold growing on corn kernels. Areas in fields that have insect- and bird-damaged ears may be affected more severely by the disease. Aspergillus flavus produces a mycotoxin known as aflatoxin, which is carcinogenic to animals that consume aflatoxin-contaminated grain. The U.S. Food and Drug Administration (FDA) has established specific action levels for aflatoxin-contaminated corn grain, which are shown in Table 1.

Table 1. FDA action levels for aflatoxin.

Animal feeds

Action level (parts per billion)

Corn products intended for finishing beef cattle


Corn products intended for finishing swine of 100 lb or greater


Corn products intended for breeding beef cattle, breeding swine, or mature poultry


Corn products intended for dairy animals


See this web site for more information.

Symptoms of Aspergillus ear rot. (Photos courtesy of Robert Bellm, University of Illinois Extension, and Don White, University of Illinois.)

Before harvesting a field, check for Aspergillus ear rot. If it is observed in a field, and if the field is covered by crop insurance, you must contact your crop insurance agent before harvesting, as the insurance will not cover losses due to aflatoxin after grain is placed in storage. (See this article by Dr. Gary Schnitkey, University of Illinois professor of agricultural and consumer economics)

Corn grain and silage samples to be tested for aflatoxin can currently be sent to the Illinois Department of Agriculture's Centralia Animal Disease Laboratory. However, the lab is scheduled to close later this year, with services moving to the Galesburg Animal Disease Laboratory.

Corn affected by Aspergillus ear rot should be dried to below 15% moisture immediately after harvest to prevent continued development of mold and aflatoxin accumulation, and for long-term storage moisture should be slightly below 13%. Cleaning grain after harvest may reduce the level of aflatoxin in that lot, since broken and cracked kernels tend to have higher levels of aflatoxin. If grain cleaning is done, it is important that the screenings not be fed to livestock, since aflatoxins are likely to be more highly concentrated in them.

For more information about Aspergillus ear rot, aflatoxin, and other corn ear molds and mycotoxins, see the presentation by Dr. Charles Woloshuk of Purdue University at the "Focus on Corn" section of the Plant Management Network.--Carl A. Bradley

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