Insect & Pests

All Insect & Pests Content
Sunflower moth, banded sunflower moth, and sunflower maggot adult.

Sunflower Pest Recap

During 2026, we will be producing a new weekly update on sunflower insect pest activity. This information will be attained via a sampling network of eight locations that are in central South Dakota.

Small weevil covered in dense reddish-orange hairs sitting on a green leaf.

Planting Date and Early Maturing Hybrids as Alternative Management Options for Red Sunflower Seed Weevil

Planting dates and early maturing hybrids can be use as alternative management options for Red Sunflower Seed Weevils in South Dakota.

Black beetle covered in gray setae that has a black rostrum.

Gray Sunflower Seed Weevils

Factsheet on the lifecycle, identification, scouting and management of Gray Sunflower Seed Weevils.

tall trees in the Black Hills

Tree Pest Alert

From seasonal issues and timely recommendations to disease diagnosis and expert advice, the Tree Pest Alert is a trusted resource for selecting, planting and caring for trees and shrubs all year round.

Green stem that is covered in light green colored aphids.

Economically Damaging Soybean Aphid Populations Detected

Soybean aphid populations continue to grow in South Dakota. This week, counts near Volga ranged from approximately 280-700 aphids per plant. Observations of these populations indicate that they are healthy and will continue to increase.

Dying patch of soybeans in an otherwise healthy field.

Scout Soybean in Drought-Affected Fields for Twospotted Spider Mites

One of the pests that typically shows up during drought conditions is the twospotted spider mite (Tetranychus urticae). Infestations of this pest were recently confirmed in Eastern South Dakota soybean and corn.

Metalic bronze green beetle on a green leaf

Japanese Beetles in South Dakota

In the last 10 years, Japanese beetle populations have remained low to absent in my garden in Brookings. However, last week I observed large aggregations of beetles feeding on smartweed that was present in my rain garden. Japanese beetles can be problematic for gardens, flowers, and trees in residential areas.

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.