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Insect & Pests

All Insect & Pests Content

Aflafla field with light colored alfalfa mixed in with green alfalfa.

Why’s My Alfalfa Field Turning White?

There have been a lot of reports of alfalfa fields in South Dakota with a white or light-brown canopy. This discoloration is the result of extensive alfalfa weevil larvae feeding.

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

Common Stalk Borer Activity Estimate: May 27, 2021

Throughout South Dakota, we still haven’t accumulated enough degree days for common stalk borers to begin moving into corn, which is a good thing. At this point in time, common stalk borer activity is still going to be limited to weeds and grassy weeds.

Seecorn maggot larva feeding on a seed in a field.

Seedcorn Maggot Degree Day Activity Estimates: May 27, 2021

In South Dakota, we have accumulated enough degree days across the state that the peak emergence of the overwintering seedcorn maggot population has passed. In most of South Dakota, we are at peak emergence of the second generation or slightly past it.

Yellow wireworm on an orange sweet potato.

Wireworms in the Garden

With warming soil temperatures, overwintering wireworms have become active throughout South Dakota. Wireworms are soil-dwelling insects that can be pests of germinating seeds, seedlings and root crops.

Seecorn maggot larva feeding on a seed in a field.

Seedcorn Maggot Degree Day Activity Estimates: May 20, 2021

Seedcorn maggots can be an early-season pest of corn and soybean in South Dakota, typically affecting crops that are emerging or have recently emerged. Seedcorn maggots can cause direct loss by destroying planted seeds.

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.