Everyone across the Corn Belt is jittery about getting this crop in the bin. One reason is that stalks are weakened due to stress. The other is that drought conditions are often conducive to Aspergillus fungal mold, especially if it turns wet later in the season. Many areas of the Corn Belt, especially those hardest hit in Illinois and Indiana, are in that category.
Chuck Woloshuk, a disease specialist at Purdue University, says it's a concern. He has already found the fungus on corn in central Indiana, but so far just in scattered locations within a field. This fungus does not move from ear to ear, he says. However, once it's shelled, it can move from kernel to kernel if infected kernels are mixed with non-infected kernels.
The question is how severe an infestation might develop. The warm weather that accompanied rain over Labor Day and into the next week favored the disease. However, cool weather which was to follow should slow it down.
Woloshuk's best advice is to get corn out of the field and dry it to prevent further development. However, it's important to know if the disease is in the field before you harvest. The best way to tell is to randomly pull back shucks and look for an olive-green mold, often near the base of the ear. To be sure you need to have samples run at the Animal and Disease Diagnostic labs at Dubois or West Lafayette, or at a commercial lab. There is a cost for these tests. In other states, check with Extension to see if an Extension-based or Land-grant –based lab runs the test. If not, seek out a commercial lab capable of checking for aflatoxin.
If you know there is some in the field and you're going to store the corn, keep it in a bin by itself. Dry it down more than you would normally. If you want to stop the growth of the mold and further production of aflatoxin, then dry it to 12 to 13%.
Expect elevators to test for aflatoxin, especially if you're in an area hard hit by the drought. Some elevators have acceptable tolerances, but it is usually very low for corn going into the human food chain or into the feed supply for dairy cattle. Hogs are also very sensitive to aflatoxin and will go off feed and perform poorly if fed ground corn containing high levels of aflatoxin.