By Janet J. Knodel
Extension Entomologist
The importance of getting bins ready for grain storage to minimize insect pest problems in bins (2013 Crop & Pest Report). The key to good grain storage is anticipating and preventing potential problems through good bin management. Before treating with an insecticide protectant, make sure that the bins are 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 should be thoroughly cleaned and grain residues removed before harvest.
A residual bin spray, such as malathion, Tempo, Diacon or a combination of chemicals should be applied to all interior 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 those 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. Spray beneath the bin, its supports, and a 6 ft. border around the outside foundation. Treat the outside surface, especially cracks and ledges near doors and fans.
The increased use of metal bins with perforated floors for grain drying and aeration has helped produce a serious insect problem in farm-stored grain. Grain dockage (broken kernels, grain dust, and chaff) sifts through the floor perforations and collects in the subfloor plenum creating a favorable environment for insect development. Unfortunately, the floors are usually difficult to remove, making inspection, cleaning and insecticide spraying in the plenum difficult if not impractical. The infested plenum may be disinfected with an approved fumigant, such as chloropicrin.
Please see the stored grains section of the 2015 North Dakota Field Crop Insect Management Guide for insecticides registered in stored grains. Always follow insecticide label directions for use of proper safety gear and safe application techniques. For additional information, please see Dr. Kenneth Hellevang’s NDSU website on Grain Drying and Handling which addresses all aspects of stored grain management, such as cooling grain to prevent insect and spoilage problems.