Skip to main content

Insect & Pests

All Insect & Pests Content

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

Common Stalk Borer Activity Estimate: June 5, 2024

In southern South Dakota, enough degree days have accumulated for common stalk borer caterpillars to begin moving from alternative hosts into corn. Fields should be monitored for leaves with signs of defoliation.

Seecorn maggot larva feeding on a seed in a field.

Seedcorn Maggot Degree Day Activity Estimates: June 5, 2024

Peak emergence of the second generation of seedcorn maggots is occurring in a few areas of the state. The rest of the state is between the second and third generation emergences.

Small black and yellow beetle feeding on the green leaf of a canola plant.

Don’t Forget to Scout Canola for Flea Beetles

Canola emergence is well underway and ahead of emergence at this time in 2023. There are three species of flea beetles that commonly infest canola and feed on the leaves.

Small white maggot next to a brown pill shaped pupa.

Monitor for Seedcorn Maggots in Wet Planted Fields

Current spring conditions, including wet soil and cool temperatures, could result in seedcorn maggot issues in South Dakota.

Seecorn maggot larva feeding on a seed in a field.

Seedcorn Maggot Degree Day Activity Estimates: May 29, 2024

Many of the northern counties are approaching enough degree days for a peak second-generation seedcorn maggot emergence to occur.

Green alfalfa weevil larvae with a white stripe running down its body.

Alfalfa Weevil Activity Prediction Update: May 29, 2024

Most alfalfa weevil larvae that were observed this week were between the first and second instar, but it is likely that later instars are present in southern counties.

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

Alfalfa Weevil Activity Prediction Update: May 24, 2024

Degree day accumulations continue to estimate alfalfa weevil activity throughout South Dakota. Alfalfa weevil activity is likely greater in southern counties, but alfalfa should continue to be scouted statewide.

Seecorn maggot larva feeding on a seed in a field.

Seedcorn Maggot Degree Day Activity Estimates: May 24, 2024

Parts of South Dakota are currently at, slightly below, or over the 1,080 degree days for the peak second generation emergence of seedcorn maggots.

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

Common Stalk Borer Activity Estimate: May 24, 2024

Throughout South Dakota, common stalk borer caterpillars are still active in alternative weed and grass hosts.

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

Common Stalk Borers and Why They Matter in Early Season Corn

Based on current degree day accumulations, the common stalk borer caterpillars are developing within weeds and grass hosts. Once the caterpillars outgrow these hosts they will begin moving into corn fields.