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Insect & Pests

All Insect & Pests Content

Green beetle larvae with a white stripe running down its body.

Alfalfa Weevil Activity Prediction Update: May 20, 2021

This week we accumulated degree days for alfalfa weevils at a rapid rate. As a result, we observed many areas of the state potentially move through more than one larval life stage.

Purple-brown caterpillar with orange head on a green corn leaf.

Common Stalk Borer Activity Estimate: May 13, 2021

The upcoming weather forecast looks warmer than the last few weeks, and that means we will begin to accumulate degree days for the common stalk borer at an increased rate.

Purple-brown caterpillar with orange head on a green corn leaf.

Common Stalk Borer Activity Estimate: April 29, 2021

As temperatures continue to warm up, degree days are beginning to accumulate a little faster for common stalk borers. Most of South Dakota is still between conditions approaching egg hatch and egg hatch occurring.

Purple-brown caterpillar with orange head on a green corn leaf.

Common Stalk Borer Activity Estimate: April 22, 2021

In its early vegetative growth stages, corn is susceptible to feeding by the common stalk borer. The hatching and movement of common stalk borer caterpillars can be estimated by using degree days.

Purple-brown caterpillar with orange head on a green corn leaf.

Common Stalk Borer Activity Estimate: May 20, 2021

Warmer weather is finally here. Although we have accumulated quite a few degree days for common stalk borers, nowhere in the state has reached accumulation levels for common stalk borer caterpillar movement into corn fields.

Purple-brown caterpillar with orange head on a green corn leaf.

Common Stalk Borer Activity Estimate: May 6, 2021

We are beginning to accumulate degree days a little faster for common stalk borers. Eggs will be hatching through much of the state, and we will continue to monitor activity as the season progresses.

Green corn leaf with common stalk borer caterpillar within.

Common Stalk Borer Activity Update: June 6, 2019

It finally warmed up and the insects have definitely become more active. However, our calculations indicate that not enough degree days have been accumulated for common stalk borer activity to warrant any scouting, but spraying field edges should be avoided through most of South Dakota in the next week.

Purple-brown caterpillar with orange head on a green corn leaf.

Common Stalk Borer Activity Update: May 30, 2019

Another cool, wet week has led to a limited accumulation of degree days. Based on our calculations, common stalk borer activity still doesn’t warrant any scouting, but spraying field edges should be avoided around Hot Springs, Winner and Vermillion.

Green corn leaf with common stalk borer caterpillar within.

Common Stalk Borer Activity Update: May 23, 2019

Not too much is new regarding common stalk borer activity when compared to last week. Another cool, wet week has led to a limited accumulation of degree days. Based on our calculations, common stalk borer activity still doesn’t warrant any scouting. We will continue to monitor the degree days and provide updates.

Green corn leaf with common stalk borer caterpillar within.

Common Stalk Borer Activity Update: May 16, 2019

The hatching and movement of common stalk borer caterpillars can be estimated by using degree days with a developmental threshold of 41 degrees Fahrenheit. Common stalk borer eggs typically begin to hatch at 575 degree days.