Reducing the likelihood of insect problems in stored grain begins with cleaning equipment that will be used to harvest, handle and store the grain. Remove all old grain and other debris where insect infestations may be harbored. After thoroughly cleaning the equipment, spray it with a residual insecticide labeled for this use. Concentrate on cracks and crevices where insects may be hiding. It is best to complete this job at least two weeks before harvest.
Clean All Equipment
Thoroughly clean the storage bin. Removal of all grain, grain products and other organic matter is essential for eliminating existing infestations. Pay attention to the outside of the bin as well. Control any weeds that are close to the bin, and remove any grain debris or excess equipment lying near the bin. Grain bins with perforated floors can be difficult to clean, but do the best that you can. Any residue remaining in the bin can reduce the effectiveness of the residual insecticide.
Spray the floor of the bin, as well as the inside walls as high as can be reached, with a residual insecticide to eliminate existing infestations. Also spray the outside of the bin, as high as can be reached, plus the ground or concrete pad surrounding the bin out to a distance of at least five feet. Spray the entire inner area of the bin according to the directions on the pesticide label.
Prepare The Grain Bin
A small compressed air sprayer can be used for spraying equipment and bins. But better penetration of cracks, crevices and other remote areas can be obtained by using a power sprayer that will develop at least 150 pounds per square inch of pressure. An exception is cyfluthrin, which can be used with as little as 50 pounds per square inch of pressure. Remove all dead insects before putting grain in the bin.
Completely seal any unnecessary openings in the bin using caulk, polyethylene foam or other suitable materials such as sheets of polyethylene. Pay particular attention to joints in the metal. At night, place a light inside the bin to find any openings that you may have missed. Or, step inside the empty bin, close the door, and look for places where daylight shines through.
The bin must be airtight if the grain is to be fumigated after it is stored.
For more information, see IPM Recommendations for Stored Grains at www.aces.edu/anr/crops/ and click on row crops, corn, then stored grains.