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Hunting for stalk borers

James Kalisch, University of Nebraska, Bugwood.org 6-20-22 stalk borer.jpg
Common stalk borers are emerging in fields, start scouting now.

While in westcentral Iowa yesterday setting up some small plot experiments, I got distracted by a long stretch of grass alongside a cornfield. I noticed some “deadheads” among the green plants and decided to dig a little deeper.

Iowa State University6-20-22 #1 20220614_114028_-_copy-400x400.jpg

I pulled up some of the dead head plants and noted holes about half-way down the plant.

Iowa State University6-20-22 #2 20220614_114629_-_copy-400x400.jpg

I used a knife to spilt the stalk just above the hole and a very unhappy caterpillar was inside.

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The caterpillar, known as common stalk borer, was about an inch in length and had a purple “saddle” on the thorax and an obvious orange head.

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The caterpillar pretty much filled up the inside of the stem and had created copious amounts of sawdust-like frass.

Iowa State University6-20-22 #6 20220614_115816_-_copy-400x400.jpg

Based on accumulating degree days estimated by a recent ICM News article, I would expect stalk borers to move to corn and soybean in central Iowa next week. The only time to act is when the caterpillars are exposed, moving from grass to crops. Take a look at field edges now, especially in areas with previous stalk borer infestations.

Source: Iowa State University, which is solely responsible for the information provided and is wholly owned by the source. Informa Business Media and all its subsidiaries are not responsible for any of the content contained in this information asset. 

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