Stored Grain Insects Threaten Crops Post-Harvest

With fewer chemical products to protect harvested grains, no-tillers will have to use cultural methods to prevent bin pests.

Regardless of your farming methods, once the combines are back in the shed, controlling insect damage of stored grain within the bin becomes a prime chore to protect your hard-won harvest

Edmond Bonjour, stored product entomologist at Oklahoma State University, says that chore is becoming more complex as EPA regulations are removing long-time stored-grain protectants chlorpyrophos and chlorpyrophos methyl from the equation. 

“The products are off the books now, and as of March 2024, there will be no more sale or distribution of the compounds,” Bonjour says. “While new protectants not containing chlorpyrophos are being developed, they are of similar chemistry to other existing products, so growers will need to consider cultural methods to maintain stored grain quality.”

In the Corn Belt, growers face issues with the maize weevil, which can fly to multiple facilities, and the Angoumois grain moth, another airborne pest that infests grain with egg clusters on wheat heads and corn ears in the field. The larvae enter kernels and can be transported to storage facilities after harvest.

In wheat-producing areas, the lesser grain borer and rice weevil are prime pests in stored grain. Both pests can fly at least 2 miles on their own and move even farther on prevailing winds.  

“Stored grain kept below 12.5% moisture should never have an issue with rice weevils, but the lesser grain borer doesn’t care,” he says. “It can survive and thrive at nearly all moisture levels from 8-16%.”

This year’s highly publicized moth populations, which rode south winds…

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Dan crummett 0618

Dan Crummett

Dan Crummett has more than 35 years in regional and national agricultural journalism including editing state farm magazines, web-based machinery reporting and has an interest in no-till and conservation tillage. He holds B.S. and M.S. degrees from Oklahoma State Univ.

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