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College of Food, Agricultural, and Environmental Sciences


Monitor Stored Grain for Mold

October 19, 2010

WOOSTER, Ohio – Ohio farmers are encouraged to diligently monitor their stored corn grain to prevent mold development.


Ohio State University Extension plant pathologists said that keeping an eye on stored grain in the bins early in the season can help producers avoid problems that too often go unnoticed or are discovered too late in the game to really do anything about.

"Even in years when there is little or no ear rot problems in the fields (a leading cause of mold development), mold may still develop in the grain bins if storage temperature and moisture conditions are favorable," said Pierce Paul, an OSU Extension plant pathologist with the Ohio Agricultural Research and Development Center.

Paul said that there have been some reports of field-dried corn producing molds in storage. Moldy kernels may contain toxins harmful to livestock if ingested in large enough amounts.

"Corn is dryer than average and much dryer than last year coming out of the field. However, concerns are that 15 percent corn or higher put into the bins is producing mold on stored kernels," said Paul.

Dennis Mills, an OARDC program specialist, said that growers should check the condition of their grain every few weeks.

"It doesn't take many wet kernels to cause problems," said Mills, who also holds an OSU Extension appointment. "Turn on the fan. When the fan is running, open one of the bin lids and smell the air exiting for signs of odor."

The plant pathologists offer the following additional guidelines for grain storage:

• Harvest at the correct moisture and adjust harvest equipment to minimize damage to kernels. Mold and mycotoxins tend to be higher in damaged kernels.

• Dry and store harvested grain to below 15 percent moisture to minimize mold development and toxin contamination in storage.

• Store dried grain at cool temperatures (36 to 44 degrees Fahrenheit) in clean, dry bins. Moderate to high temperatures are favorable for fungal growth and toxin production.

• Periodically check grain for mold, insects, and temperature.

• If mold is found, send a grain sample for mold identification and analysis to determine if toxins are present and at what level.

• Clean bins and storage units between grain lots to reduce cross contamination.

For the latest crop updates refer to the OSU Extension Crop Observation and Recommendation Network (C.O.R.N.) newsletter at


Candace Pollock
Dennis Mills, Pierce Paul