A Purdue University Extension entomologist says cleaning storage bins before harvest can prevent insect infestation and reduced grain quality.

Indiana’s corn harvest this fall is projected to yield a record crop, with many producers storing grain until next spring or summer. Linda Mason, associate professor of ecology and food industry pest management, says grain bin cleanup now is important to prevent infestations.

"The principal insects that cause damage are the adult and larval stages of beetles and the larval stages of moths," Mason says. "Damage by these insects includes reducing grain weight and nutritional value and, by causing contamination as live or dead insects, odor, mold and heat damage that reduces grain quality."

Mason says newly harvested corn is contaminated when mixed with infested grain already in storage bins, combines, wagons, bucket lifts or grain-handling equipment. Insects also find their way into bins through livestock feeds, contaminated grain piles or rodent burrows.

To prevent insect infestations, Mason says there are good management practices producers can follow before putting harvested grain in storage bins.

Combines, truck beds, augers and wagons need to brushed or vacuumed to remove insect-infested grain and debris, Mason says. The walls, ceilings, ledges, rafters, fans and aeration ducts of empty bins also need to be swept. If fans are not being used, producers should cover them to keep insects from entering the bin through the aeration system, she says.

"This debris usually contains insect eggs, larvae, pupae or adults ready to infest newly harvested grain," Mason says. "When you remove the debris from the storage area, remember to dispose of it properly, according to area, state or federal guidelines."

Once grain bins are clean, Mason says producers should spray bin walls, ledges, rafters and floors with an approved insecticide, such as chlorpyrifos-methyl or cyfluthrin. Insecticide also should be applied on the bin’s outside walls up to 15’ high and around the base. The insecticide will create an insect barrier around the bin.

Cleaning the bins is important, but the area around the storage structure should be maintained as well. Remove vegetation within 10’ of the storage area and apply an insecticide on the soil, Mason says. She suggests using a residual herbicide to get rid of any unwanted plant growth.

Another way to keep insects out of grain bins is to repair all damaged areas on the structure. Mason says this also keeps water from leaking onto the grain, causing mold.

"Sanitation is the key to pest management," she says. "It is the first line of defense in keeping insects out of your grain."

Check out Post-Harvest Grain Quality and Stored Product Protection Program at pasture.ecn.purdue.edu/%7Egrainlab/