Farmers who triumphed over insects during the growing season could find their victory short-lived when they store their grain, says a Purdue University entomologist.

Grain bins can harbor destructive pests, says Linda Mason, a food pest management and stored grain specialist. She advised farmers to prepare their bins ahead of harvest.

"Preparing bins for storage now goes a long way toward preventing insect infestations during the summer," Mason says.

"Several species of insects may infest stored grain. The principal ones are the adult and larval stages of beetles and the larval stage of moths. Insect damage reduces grain weight and nutritional value, causing contamination, odor, mold and heat damage problems that reduce grain quality."

Newly harvested grain becomes infested with insects when it contacts infected grain in combines, truck beds, wagons, grain-handling equipment, augers, bucket lifts, grain dumps or grain already in a bin, Mason says. Insects can crawl or fly into bins from nearby accumulations of old contaminated grain, livestock feeds, bags, litter or other cereal products.

"Insect infestations can be prevented with good management practices," Mason says. Those practices include:

* Brushing, sweeping out and/or vacuuming combines, truck beds, transport wagons, grain dumps, augers and elevator buckets, in order to remove insect-infested grain and debris.

* Sweeping or brushing down the walls, ceilings, ledges, rafters, braces and handling equipment in empty bins.

* Removing debris from fans, exhausts, aeration ducts and, when possible, beneath slotted floors.

* Disposing of the debris. It can contain insect eggs, larvae, pupae and/or adult insects.

* Treating the inside of clean bins with approved insecticide. Wall surfaces, ledges, braces, rafters and floors can be sprayed with Storcide II (chlorpyrifos-methyl – the active ingredient in Reldan-stored grain insecticide – and deltamethrin), Tempo (cyfluthrin), Diacon II (methoprene) or various diatomaceous earth (D.E.) products.

"You should create a perimeter barrier," Mason says. "Outside, complete this barrier by treating the bases and walls up to 15 ft. high, plus the soil around the bins. Storcide II must be sprayed in a downward spray only and, if treating the inside of structure, it can only be applied from the outside."

* Clearing away all vegetation growing within 10 ft. of a bin and, preferably, the whole storage area. Follow by spraying the cleaned area around the bin with a residual herbicide to remove all undesirable weedy plants.

* Repairing and sealing all damaged areas to grain storage structures. "This is not only to prevent insect migration into the bin, but also to prevent water leakage, which leads to mold growth," Mason says.

Don’t store newly harvested grain with old grain. "Whenever fans aren’t operated, cover and seal them," she says. "This reduces the opportunity for insects and vertebrates to enter the bin through the aeration system."

Grain placed in a bin can be treated with such approved insecticides as Storcide II, which has CODEX MRL tolerances. "Labeled crops protected with Storcide II may be shipped to international markets and any of the D.E. products," Mason says.

For more information about crop pests and management options, read the Purdue Pest and Crop Newsletter. The newsletter is available online at http://www.entm.purdue.edu/Entomology/ext/targets/p&c/index2006.htm.