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Content by Patrick Wagner

Green caterpillar with prolegs at the end of its body that form “V” shape.

Diamondback Moth Caterpillars Active In South Dakota

Diamondback moth caterpillars have been observed in South Dakota gardens. These pests feed primarily on cole crops, such as broccoli, Brussel sprouts, cabbage, cauliflower and kale, leaving behind irregular-shaped holes.

Illustration of a stable fly, horn fly and face fly.

Fly Control Considerations for Cattle on Pasture

Along with being irritants to livestock, horn flies, face flies and stable flies are economically important to producers due to their negative impacts on milk production and calf weaning weights.

Brown insect with two pincher like appendages at the end of its body.

Earwigs Are Active

Although earwigs typically prefer wet conditions, quite a few have been observed so far this year. It’s important to remember that watering lawns or potted plants around the house provides ideal earwig habitat.

Seecorn maggot larva feeding on a seed in a field.

Seedcorn Maggot Degree Day Activity Estimates: June 3, 2021

We are currently between the second and third generation peak emergences in South Dakota. Seedcorn maggot management must be done before planting, or the populations can be avoided by not planting during times of peak emergence.

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

Alfalfa Weevil Activity Prediction Update: June 3, 2021

It has been a busy week for alfalfa weevils. Throughout the state, alfalfa weevils have been causing significant feeding damage. We recommend scouting alfalfa fields for the next week and treating when necessary.

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.

Green corn leaf with ragged holes through-out caused by common stalk borer feeding.

Common Stalk Borers Observed in South Dakota Corn

While scouting corn this week, clear signs of common stalk borers were observed. Although our degree day estimates indicate that common stalk borers probably aren’t moving into corn yet, they can be forced into corn fields in certain situations.

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

Alfalfa Weevil Activity Prediction Update: May 27, 2021

Alfalfa weevil activity is still being reported across much of the state. Although the degree day estimates for South Dakota indicate that much of the state has populations that are pupating, these estimates are not accurate. Scouting should continue throughout South Dakota.

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.