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Crop Watch: Imagine finding these monster bugs in your cornfield!

Tom Bechman, Editor, Indiana Prairie Farm

August 19, 2016

3 Min Read

No, the Dow AgroSciences demonstration farm near Sheridan, Ind., isn’t a modern-day version of Jurassic Park. There are certainly no dinosaurs, and there really aren’t giant bugs, enlarged many times over. It just looked like that during a field day earlier this summer. Huge insects on poles hovered over knee-high to waist-high corn.

Dow AgroSciences was making a point. The new PowerCore trait available in its seed brands for 2016-17 will control the three giant insects pictured here, plus three others.

Here is a closer look at these three hombres.

1. Meet the western bean cutworm (top right in bottom photo).

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PowerCore has control over this insect with a single mode of action. Some aboveground GMO-insect traits already on the market also have one mode of action for this insect. Some don’t control this insect. In areas where western bean cutworm is a problem, it can be devastating. In Indiana, one of the largest concentrations is in the northwest part of the state. 

According to the Purdue University Corn and Soybean Field Guide, two distinct, dark rectangles located immediately above the insect's orange head help identify it when larvae are larger. However, they don’t have to be as large as the one in this photo to identify!

Western bean cutworm is particularly damaging because more than one worm often burrows into a single ear of corn. As many as three or four may make their home in the same ear. Once feeding opens up the husks, water can move into the ear, setting it up for sprouting and disease infection — particularly ear molds.

2. Here comes the black cutworm (front center in photo at left).

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PowerCore also controls black cutworm with a single mode of action. A competitive product on the market now also has one mode of action for black cutworm. Some products don’t control it. Even though two traits exist that control this pest with one mode of action, it’s not the same mode of action in each case. The proteins are typically different.

According to the Purdue guide, this spring-attacking insect can vary in color, from light gray to nearly black. Skin texture is coarse and granular. It primarily causes damage by cutting off young seedlings when feeding early in the season.

3. Corn earworm is on the march (left in photo).

Two modes of action in PowerCore work on this insect. Another competitive product also has two modes of action for corn earworm. Some aboveground Bt products don’t control corn earworm.

The Purdue guide says larvae can be green like this one, pink, tan or even dark brown, with light and dark stripes running lengthwise on the body. This insect is famous for feeding on kernels near the tip of the ear.

The other three insects PowerCore traits control are European corn borer, southwestern corn borer and fall armyworm. Look for a story on them later this week.

About the Author(s)

Tom Bechman

Editor, Indiana Prairie Farm, Indiana Prairie Farmer

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