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Adam Varenhorst

Associate Professor & SDSU Extension Field Crop Entomologist

605-688-6854

Berg Agricultural Hall 226
Box 2100A
Brookings, SD 57007

As the SDSU Extension Field Crop Entomologist Adam serves South Dakota stakeholders by addressing insect pest issues in field crops. He conducts applied research that focuses on corn, soybean, wheat and sunflower. Additionally, he assists the other extension entomologists to address questions pertaining to insect questions for the home and garden, urban insect pests and general entomology questions.

State & Regional Offices

SDSU Campus

Also by Adam Varenhorst

Small beetle with elongated black snout. Beetle is red-orange in color.

Vertento® Insecticide Approved for Red Sunflower Seed Weevil Management

Recently the Environmental Protection Agency approved a Section 18 Emergency Exemption label for Vertento® Insecticide for use on sunflowers for red sunflower seed weevil management in South Dakota. This exemption is effective from July 15 to August 31, 2026.

Stable fly, face fly, and horn fly.

Fly Management for Cattle

There are several species of flies that can reduce the production value of livestock, particularly during hot, dry weather. To manage these pests, it’s important to be able to accurately identify them and understand their life cycles.

Numerous nymph grasshoppers feeding on corn.

Large Grasshopper Nymph Populations Detected in Southeast South Dakota

This week we received several reports of large grasshopper populations originating from southeast South Dakota. The populations were well above threshold and actively defoliating crops.