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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
Green cloverworm caterpillar, Thistle caterpillar, and Oblique banded leaf roller.

Several Species of Caterpillars Are Actively Defoliating Soybean

There are several species of caterpillars that have recently been observed in a single soybean field. The species include the green cloverworm, cabbage looper, alfalfa, thistle, and oblique banded leaf roller caterpillars.

Dense swarm of mosquitoes in the evening sky

West Nile Virus Update: July 29, 2026

As of July 30, 2026, the South Dakota Department of Health indicated that West Nile Virus positive mosquito pools have been detected in Brown, Codington, Hughes, Lincoln, and Minnehaha counties in South Dakota.

Blue green aphids present on a corn tassel.

Aphid Populations Observed in South Dakota Corn Fields

During the last week, we have observed low level aphid populations in corn fields. Although aphid populations can reach high densities in corn, their presence doesn’t indicate guaranteed yield loss.