Clean Up Grain Bins to Reduce Insect Pests

This page was adapted from the article, "Clean Up Grain Bins to Reduce Insect Pests," which appeared in Crop & Pest Report on August 25, 2022. 

The key to preventing grain insect problems in grain bins is cleaning empty grain bins and trucks hauling new grains. Any old grain or even dust residue left in the bin is enough for some grain insects to survive and lead to new infestations reducing the quality and salability of your new grains. Bins need to be super clean, completely empty and free of insect-infested grain. Leftover grain should be removed from the bin, and the walls should be swept and vacuumed. All grain handling equipment including augers, combines, trucks and wagons also need to be thoroughly cleaned and grain residues removed before harvest.

After cleaning, be sure to check for any cracks, crevices or holes in grain bins and seal them up. This is how most grain insects get into the bins and storage facilities.

The area outside of the grain bins needs to be cleaned and treated. Remove weeds and vegetation, up to 10 ft border around empty grain bins. Treat the outside surfaces, especially cracks and ledges near doors and fans to prevent insect pests from entering grain bins.

Once the cleaning and repairs are done, it’s time to spray a residual bin spray or surface treatment, both inside and outside the grain bin. Some insecticide examples are malathion, Tempo, Centynal EC, Diacon IGR Plus (insect growth regulator + adulticide), or a combination of chemicals. They should be applied to bin surface areas 2 to 3 weeks before new grain is placed in the bin. The treatment will kill insects emerging from their hiding places (cracks, crevices, under floors and in aeration systems). Also, insects crawling or flying in from the outside will be killed. Apply the spray to as many surfaces as possible, especially joints, seams, cracks, ledges and corners. Spray the ceiling, walls and floors to the point of runoff. Use a coarse spray at a pressure of more than 30 lb per square inch and aim for the cracks and crevices.

Any grain that will be stored for long-term, more than 10 months, should have an insecticide protectant on it to maintain the commodities quality and protect your investment. Cooling the grain to <50⁰F will keep insects dormant, and temperature < 20-25⁰F will kill insects (see chart on next page). Please see the stored grains section of the North Dakota Field Crop Insect Management Guide for insecticides registered in stored grains.

For additional information, please see Grain Drying and Handling which addresses all aspects of stored grain management, such as cooling grain to prevent insect and spoilage problems.