Purdue News

January 30, 1998

Stored grain at risk from warm weather

Cooperative Extension Service grain quality specialist Dirk Maier said corn that wasn't dried below 15 percent moisture at harvest is more susceptible to mold now because of recent weather.

Daytime temperatures for January averaged 38 degrees Fahrenheit, and nighttime temperatures were 27. Average humidity was 91 percent, according to Purdue assistant state climatologist Pam Beneker.

Symptoms of corn going out of condition include crusting of the top layer because of sprouting and molding, soggy surface corn because of condensation and moisture absorption, and hot spots within the top few feet of the bin. Sour air from fan exhaust or steam escaping the bin in early morning also are good indicators of corn going bad. "You'll know it when you smell it," Maier said.

Farmers holding onto corn and waiting for better prices may want to reconsider if the grain goes bad, he advised.

"The best thing farmers can do is sell it, because this is not corn that will store well into spring," Maier said.

If farmers choose to keep the grain, they'll need to break up the crust and run fans until symptoms disappear. Grain peaks should be cored.

"Lastly, check bins at least twice a week, if not every day," he said. A dust mask should be worn to reduce exposure to mold spores.

Four to five days of freezing temperatures with aeration will be needed to stop the spoilage process in a typical storage setup, he said. "The problem isn't with the average temperature so much as the daily highs," he said. The challenge is cooling off all the grain in the bin, including hot spots.

Those hot spots also may wake up the insects. According to Extension entomologist Linda Mason, if the grain temperatures move above 55, or stay between 30 and 40 for any length of time, insects could come out of diapause, the entomological equivalent of hibernation. That means farmers who are used to checking for insect infestations in May, June and July will want to start looking in March and April this year.

Mold and insect activity tend to fuel each other, she said.

One additional caution: a 1996 Purdue farm safety study showed an increase in grain entrapments fatalities when farmers are working with spoiled grain.

CONTACTS: Maier, (765) 494-1175; e-mail, maier@ecn.purdue.edu; Beneker, (765) 494-8105; Mason, (765) 494-4586

Compiled by Chris Sigurdson, (765) 494-8415; E-mail, sig@ecn.purdue.edu
Purdue News Service: (765) 494-2096; e-mail, purduenews@purdue.edu

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