Corn rootworm. A pest which causes over a billion dollars’ worth of damage annually across the United States and has crept up in numbers in Wisconsin. Emily Bick, UW-Madison Entomology Professor explains what we can expect this year from this pest and how farmers can take proactive measures to mitigate its impact on their crops.
Corn rootworm beetle pressure persists. Based on the high adult corn rootworm pressure observed last August, southern and western Wisconsin corn producers have been advised to closely review their rootworm management plans for 2023.
“Corn rootworm can cause extensive damage to corn crops,” says Bick. “Larvae feed on roots in late spring and early summer, causing stalks to tip over. Adults feed on leaves and silks in the late summer, inhibiting pollination. The number of adults in your field in the fall is an indicator of the larvae to be there in the spring.”
When scouting your field for rootworm, Bick says to count them before seventy percent of the plants are in the process of silking and walk in a “W ” shape pattern to reach different areas of the corn field. If you know you’ll have rootworm, try seed variations. Rootworm is adaptive to repetitive pest management so crop rotation is a great solution to combat this pest.
Other pests to beware of this year are soybean leaf beetle and alfalfa weevil. Bick says if you cut a little bit early, you might be able to harvest the crop before the insects get out of hand. You can also use insecticides.
A big incoming pest that she says farmers should watch for is the soybean gall midge. It is currently in our neighboring states and Bick expects it will be in Wisconsin soon. She encourages farmers to keep in contact with their local extension educators for more guidance as this insect moves to Wisconsin.
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