Mild Winter Means Insect Populations Could Soar

Insect sticky trap showing higher-than-normal populations of Armyworm. ( Erich Eller )

This past winter didn’t bring harsh, cold temperatures like in years past, which means not only did many winter annual weeds survive, so did insect pests. This season, you’ll want to scout for infestations, check to make sure your seed traits are defending against pests and be willing to pull the insecticide trigger if insect populations reach threshold levels.

“We had a very mild winter, so insects just did not die out,” says Erich Eller, owner of ForeFront Ag Solutions. “I’m gearing up for more scouting and an increase in insects and diseases.”

One specific pest to watch for is black cutworm (BCW). Moths overwinter in warmer southern states, but they might not have had to travel as far south this year. That means you might expect populations to show up sooner, with more vigor.

Corn is at the greatest risk when it’s less than 15” in height, and stand loss is potentially greater when the growing point is above the ground. If BCW cuts the plant off at the base but the growing point is below ground the crop might be able to recover. Consider a rescue treatment if 3% of the stand has BCW cutting damage. But be aware that damage can appear in the form of small pinholes on the leaves, too.

Eller says his team is also looking for armyworm—with sticky traps catching six to eight moths a day. In a typical year, he says you’d only catch two or less per day. Right now armyworms are after winter wheat, but it won’t be long before they start crawling into young corn fields. Threshold to spray, according to Eller, is 4.2 moths per day.

Armyworm isn’t a typical consideration during emergence and early growth stages but says in some areas this pest can cause stand damage. They are bright green when small and change to a dull green or brown as they grow. The adult moth has light brown wings with white dots on each forewing.

Read more about insect pests here:

Stop These Early Season Pests