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Insect & Pests

All Insect & Pests Content

Small white maggot next to a brown pill shaped pupa. Both a on soil with a yellow tape measure behind them

Watch for Seedcorn Maggots in Emerging Soybean

Of all of the potential early season pests, the seedcorn maggot is rarely an issue in South Dakota. However, we have started receiving reports of soybean fields that have poor emergence or seedling stand reductions occurring.

Small, green soybean aphids on a green, soybean stem with pink flower.

Don’t Get Surprised. Start Scouting for Soybean Aphids.

Soybean aphid populations have been observed in neighboring states and in very small populations in South Dakota. It is a good reminder that soybean aphid scouting should occur throughout the growing season to prevent population outbreaks and yield loss.

Green caterpillar with light colored stripe on back. Caterpillar is feeding on green plant.

Monitor Soybean and Sunflower for Alfalfa Webworm Caterpillars

In the last couple of weeks, we have received numerous reports of small green caterpillars in soybean and sunflower. The caterpillars have been described as producing webbing and moving extremely quickly when disturbed.

Black caterpillar feeding on green soybean leaf.

Start Scouting Fields for Thistle Caterpillar Activity

Many of our summer insect pests overwinter in the Southern U.S. and rely on wind currents to travel north in the spring and summer. The thistle caterpillar is one of those pests.

Two caterpillars feeding on soybeans. Top: Green cloverworm caterpillar. Bottom: Alfalfa caterpillar.

Soybean Defoliators Are Active

It’s that time of the season when numerous defoliating insects can be observed in a single soybean field. Most of the defoliators at this time are green cloverworms and alfalfa caterpillars.

Grain storage bin.

Steps to Prevent Stored Grain Infestations

As wheat harvest is underway it is important to ensure that grain bins are prepared in the best possible manner to prevent insect infestations. There are seven steps that can be taken to help reduce the chances of having infested grain.

Left: Black beetle with a red head on soybean leaf. Right: Green soybean leaf with small holes near the center and edges.

Monitor Soybean for Redheaded Flea Beetle Feeding

An additional soybean defoliator to monitor this week is the redheaded flea beetle. Although these beetles are typically not a serious soybean pest, large populations can result in considerable defoliation.

Small white insects with tent like wings present on a green leaf.

What Are These Small White Insects in My Soybean Field?

During the last two weeks we have received reports of increasing numbers of small white insects present on soybean. The insects in question are whiteflies.

: Gray caterpillar with dark markings, white splotches and a white stripe running down the middle of its back.

Monitor Alfalfa for Cutworm Activity

During the spring, there are a lot of insects to scout for in alfalfa. One pest group that should be focused on right now are cutworms. There are a couple of cutworm species that are active earlier in the season than others.

A small black bug with tan margins on the wings. This insect is resting on a blade of grass that is green with white spots.

Be on the Lookout for Black Grass Bugs

It’s time to begin scouting pasture and wheat for the presence of black grass bugs. Last year, we saw the highest populations in areas of Central and Southwestern South Dakota. If left untreated, black grass bug populations tend to increase year after year.