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Know your corn ear rots to determine if mycotoxin could be an issue

Know your corn ear rots to determine if mycotoxin could be an issue
Some fungal ear rots on corn produce toxins and others do not.

If you haven't found a few ears with ear rot already this fall, then you're living a charmed life or you haven't walked many fields.

Related: Stalk and ear rot diseases developing early in few fields

Kiersten Wise doesn't expect it to be a huge problem at this point, but yet she has found moldy ears of at least two different kinds of ear rots in some fields around the state.

"I've found some fusarium ear rot, and more cases of Diplodia ear rot so far," says Wise, Purdue University Extension disease specialist.

Ugly ear: Diplodia ear rot has invaded the ear Kiersten Wise held in her right hand. Although ugly, this mold does not produce a mycotoxin. The ear in her left hand has fusarium rot, which produces mycotoxins.

Determining if you have ear mold is one reason to walk fields now, she says. Mark fields with ear mold for early harvest – that's because molds continue growing until moisture content drops to around 15%. If you let corn dry in the field and there is a mold problem, the mold will continue to grow as well. And if it produces a mycotoxin, the mycotoxin will continue to increase in concentration.

Mycotoxins are still produced by fungi that produce mycotoxins even when corn is shelled and binned – until the gain is dried to 15% moisture or below.

Identifying which mold you have in a field is crucial, she says. For example, diplodia ear rot, which typically covers the ear with an ugly, fuzzy white mold, doesn't produce mycotoxins. However, fusarium ear rot does. Symptoms are generally also white mold, but usually only on part of the ear. The symptoms can vary. It may also display black discoloring around the edges of the kernels. It's more obvious if you break an ear in half.

Related: Corn ear rot exposed

Not only will mycotoxins lead to docks at the elevator if you sell grain, but they also affect feeding value because mycotoxins can affect livestock. Hogs are particularly sensitive to certain mycotoxins. It's also a big issue in specialty hybrids intended for food consumption.

Learn how to identify molds, and look for them now, Wise recommends.

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