Skip to main content

Search

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

Alfalfa Weevil Activity Prediction Update: May 13, 2021

Although last week was warmer, we still didn’t accumulate a lot of degree days for alfalfa weevils. However, the upcoming forecast looks more favorable for alfalfa growth and alfalfa weevil development.

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

Common Stalk Borer Activity Estimate: May 13, 2021

The upcoming weather forecast looks warmer than the last few weeks, and that means we will begin to accumulate degree days for the common stalk borer at an increased rate.

Young corn emerging in a no-till field.

Estimating Corn Emergence With Growing Degree Days: Data from May 7, 2021

With corn planting well underway in South Dakota, the next step is monitoring its emergence. One of the factors that can speed up or delay corn emergence is air temperature.

Two photos of alfalfa weevils during different lifecycle stages. The left is the larva stage and has a longate, green larvae that looks like a caterpillar with white stripe running down the body and brown h

Alfalfa Weevils Are Active, and It’s Time to Scout

Scouting and managing alfalfa weevils when they reach the determined thresholds can prevent yield loss and encourage healthy regrowth of infested alfalfa stands.

Two, dark green aphids on a bright green leaf.

Small Aphid Populations Observed in Wheat

This week we received the first report of aphids in wheat for the 2021 season. The populations won’t be increasing rapidly until the daily temperatures warm up, but it is still a good idea to scout fields and determine if aphids are present.

Wheat tillers with lower leaves covered with tan-brown lesions. The ground beneath has wheat stubble from previous wheat crop.

Scout for Tan Spot in Winter Wheat

Tan spot was observed in a few winter wheat fields scouted recently. It is important to scout winter wheat for tan spot and other early diseases developing before deciding to apply an early-season fungicide tank mixed with herbicide.

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

Alfalfa Weevil Activity Prediction Update: May 20, 2021

This week we accumulated degree days for alfalfa weevils at a rapid rate. As a result, we observed many areas of the state potentially move through more than one larval life stage.

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

Common Stalk Borer Activity Estimate: May 20, 2021

Warmer weather is finally here. Although we have accumulated quite a few degree days for common stalk borers, nowhere in the state has reached accumulation levels for common stalk borer caterpillar movement into corn fields.

White butterfly with black markings on wings, resting on a green leaf.

Cabbage White Butterflies Are Here!

Keep an eye out for cabbage white butterflies in your garden. These butterflies lay eggs on the underside of the vegetable leaves. Once the eggs hatch, their caterpillars feed on cabbage, broccoli, Brussel sprouts, cauliflower, kale, turnips and radishes.

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.