Aflatoxin is about the dirtiest non-four letter word there is (pardon me while I wash out my mouth and sanitize the keyboard.) It is just as prevalent as reality TV shows and political attack ads, and carries about the same value.
Nevertheless, it is in your corn, thanks to the environment, and many elevator managers are holding their nose, crossing their fingers, and praying that you didn’t have any in the load you just dumped. Others are spot checking, some are testing most loads, and some are rejecting loads of corn because of the high contamination. And many (possibly most) farmers are oblivious of the problem and are storing contaminated corn in their bins, where the concentration can increase. What do you need to know and do? Here is some help…
What does it look like?
If you find corn with an olive-green mold, you have corn with the fungus known as aspergillus ear rot, which over time and with the correct moisture will produce aflatoxin, a cancer-causing agent. Corn with aflatoxin can be rejected at grain elevators because it could get into the food chain, and it can be rejected at ethanol plants, where it will be concentrated in the DDGS’, preventing its use as a livestock feed. When rejected, whether at an elevator, processor, or feedlot, the producer may have a truckload of contaminated corn, which no one wants, along with the 100,000 more bushels of corn in the grain bin at home.
So, how do you know if you have it, before you harvest it and cannot do anything with it? The first answer is to scout your fields and look for aspergillus. The University of Nebraska suggests that “Ear rot diseases and aflatoxin are not evenly distributed across fields or in the grain, so scouting and/or sampling should include a substantial portion, at least several acres. The presence of the fungus in kernels does not always correlate well with the presence of aflatoxin, nor does the absence of visible fungal growth necessarily indicate the absence of aflatoxin.
- Open husks to view a large number of ears.
- Look for the presence of dusty yellow-green to olive-green spores, especially on the surface of damaged kernels or ear tips (Figure 1).
- Pay special attention to higher risk areas., such as drought-damaged fields, including (dryland) fields and non-irrigated pivot corners; fields or areas with higher incidence of corn ear-feeding insects, such as the corn ear worm; and grain damaged before or during harvest or after harvest while in storage.