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Winter primer on insect trapping

Most farmers cringe at the thought of insects in their cornfields. Mark Lawson, Danville, invites them. In fact, sometimes he inoculates plots to make sure insects are present. Then he traps, keeps records and notices how well hybrids with insect-resistant traits handle the pests.

Lawson is a field agronomist for Syngenta Seeds. Lately, he’s concentrated on insects that are controlled by the Agrisure Viptera trait Syngenta is introducing. This new event controls a wide range of Lepidoptera pests, including fall armyworm, corn earworm, black cutworm, dingy cutworm, western bean cutworm and more. Coupled with the Agrisure 3000GT triple stack, the Agrisure Viptera 3111 trait stack picks up most pests that can cause economic damage.

Lawson saw the effects in a research plot near his home. “Hybrids with traits fended off insects,” he notes. “They can cause significant damage to susceptible hybrids.”

After working with insects for a long time, Lawson has become efficient at trapping moths. He typically has traps out for at least three different insects. Traps help determine how many insects of a specific type he can expect.

Insect activity varies by region. Trapping helps Lawson better estimate when a new pest moving into the area might become more important.

“We saw twice as many western bean cutworm moths here as we did a year ago,” he notes. The pest is most prevalent in the northern third of Indiana, causing considerable damage to unprotected hybrids.

“If things continue, it may be an important insect here within a couple of years,” he adds.

Corn earworm is typically a bigger problem farther south. Lawson saw considerable activity last year.

Lawson uses different traps designed by entomologists based on lifestyles of various species. They’re placed at different heights within or near the crop canopy.

When to scout

Scouting may be your ticket if all your hybrids don’t carry insect resistance and you’re not sure how widespread each insect is in your area. The key is knowing when to trap.

The Purdue University Corn & Soybean Field Guide, published by The Purdue Crop Diagnostic and Training Center, contains an excellent calendar that indicates when you should begin scouting and be alert for various pests. Here are the key activity times for several pests:

black cutworms, other cutworms: the end of April through late June

armyworm: May 1 through early July

corn rootworm larvae: late May into early August

first brood corn borers: June 1 through early August

corn rootworm adults: July 1 into early October most years

corn earworm: July 1 into early October

western bean cutworm: July 1 into early October

second brood corn borers: early July through September

fall armyworm: mid-July to very early October

Scouting periods may vary in any given season. In 2010, due to the warm, fast-paced season, activity periods for some insects ran ahead of schedule.


Insect hunter: Mark Lawson prepares to inspect a trap for fall armyworm moths in mid-August.

This article published in the January, 2011 edition of INDIANA PRAIRIE FARMER.

All rights reserved. Copyright Farm Progress Cos. 2011.