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Early reports seem to indicate grain quality for 2021 should be strong; however, as always, there have been a few reports of corn ear rots around the state.

The most common of these rots are diplodia and trichoderma.

Diplodia ear rot can be characterized by a white or gray mold that covers the ear and is usually associated with a lighter-than-normal ear. This fungus thrives when we have wet, humid conditions when the corn is silking as well as up to three weeks after silking.

Corn that is showing a greenish or blue mold that is growing between the kernels and over the cob is likely trichoderma ear rot.

Depending on the severity of these rots, they will lead to a decrease in yield, and may hit the farmer in the pocketbook once again as they likely get docked a certain price per bushel upon delivery.

Aside from financial concerns, some ear rots (not all) are also a problem as the fungi are capable of producing toxic compounds known as mycotoxins, which can be toxic to animals and humans.

Prior to harvest, it is important to scout for these rots, as although it is too late to prevent them, there are strategies to help mitigate their damage.

Fields suspected to have a higher susceptibility to rot should be harvested first when the time comes, as the longer the corn sits in the field it will only increase the likelihood of fungal growth. Most ear rot fungi will continue to grow until the grain moisture is less than 15 percent.

Therefore, it may be worth it to harvest this grain early and then dry it down accordingly. It is also possible to adjust the combine to discard lightweight and damaged kernels, as these are the most likely kernels to have fungal issues.

The combine should be cleaned thoroughly after harvest to prevent contaminated grain from getting into quality grain that is harvested later.

In regards to storing infected grain, it is important to dry and cool the grain as quickly as possible to prevent further fungal growth. The standard recommendations for long-term storage are to dry contaminated grain to less than 13 percent moisture and to cool it to 30 degrees Fahrenheit.

Whenever possible, only store affected grain during the cold weather season.

Additionally, broken kernels and fine material (called “fines”) will accumulate in the center of the storage bin during filling unless the bin is equipped with a spreading device. This central core of fine material will hinder uniform air movement through the grain mass, which increases the risk that the grain will spoil.

Withdraw grain from the bin after you fill it, or “core” the bin to remove most of the broken kernels and fine material that accumulate there. Although it can be time consuming and costly, cleaning the grain prior to delivery can greatly reduce contamination and help with price docking.

For further information on ear rots and mycotoxins, visit https://bit.ly/3t7vl7d. There, you will find specific publications on identifying different ear rots and mycotoxins. You will also find helpful advice on testing for mycotoxins as well as managing and storing infected corn.

Andrew Westfall is director of Purdue Extension White County (Ind.).

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