Wet Wisconsin: Moldy corn and crop insurance

It’s been a warm and wet summer and flooding has recently hit many areas in Wisconsin. Due to the heavy moisture we have seen during the 2016 growing season, Wisconsin farmers should be especially aware of moldy corn this year.
Molds can cause serious problems if fed to livestock and can be food safety problems in the supply chain. Buyers will also be looking for moldy corn and other quality problems; ear rots have been reported, as well as some grain sprouting on the ear. For those with crop insurance, quality losses due to moldy corn can trigger indemnities if losses are large enough. Farmers suspecting losses due to moldy grain should contact their crop insurance agents before they harvest. The company will follow-up and tell you how to proceed.

Ear rots caused by fungi in the groups Diplodia, Fusarium, and Gibberella will be the most likely candidates in 2016. Fusarium and Giberrella are typically the most common fungi on corn ears in Wisconsin.

This group of fungi not only damage kernels on ears, but can also produce toxins called mycotoxins. These toxins can threaten livestock that are fed contaminated grain. Grain buyers actively test for mycotoxins in corn grain to monitor mycotoxin levels to be sure they are not above certain action levels established by the U.S. Food and Drug Administration (FDA).

The FDA has established maximum allowable levels of mycotoxins in corn and corn products for human consumption ranging from 2-4 parts per million (ppm). For animal feed, maximum allowable levels range from 5 ppm for horses to 100 ppm for poultry.

Diplodia ear rot does not produce mycotoxins, but can damage grain.This disease is often more severe in years where dry weather precedes silking, followed by wet weather immediately after silking. While this disease does not result in mycotoxin accumulation, it can cause grain yield loss and quality issues. Before harvest, farmers should check their fields to see if moldy corn is present. Similarly, during harvest they should carefully monitor the grain for mold.

If substantial portions of fields appear to be contaminated with mold, it does not mean that mycotoxins are present and vice versa. Appropriate grain samples should be collected and tested by a reputable lab. Work with your corn agronomist or local UW Extension agent to ensure proper samples are collected and to identify a reputable lab.

If tests show high levels of mycotoxins in grain, that grain SHOULD NOT BE BLENDED with non-contaminated corn. Mycotoxins are extremely stable compounds: freezing, drying, heating, etc. do not degrade mycotoxins that have already accumulated in grain.

Quality losses due to moldy corn are insurable losses for those with crop insurance, but to claim indemnities, growers must follow crop insurance rules. If you suspect mold issues, contact your crop insurance agent before harvesting, storing or selling the corn. The key is to communicate with your crop insurance agent before harvesting.