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Insect & Pests

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Two mites. From left: Green leaf with two yellow spider mites with dark spots. Green leaf with yellow spider mite.

Spider Mites Reported in South Dakota Crops

With drought conditions continuing in South Dakota, it isn’t surprising that two-spotted spider mite infestations are being reported throughout the state. With hot temperatures in the forecast and limited chances for precipitation, we can expect spider mite populations to thrive in infested fields.

Dark-colored aphids on a green stem.

Cowpea Aphids Infesting Alfalfa

Typically, we worry about pea aphids in alfalfa. However, we noticed that cowpea aphids were present on alfalfa this week. If left unmanaged, cowpea aphids can stunt alfalfa, reduce yields and even kill the plants during severe infestations.

Alfalfa plant that has numerous holes in the leaves.

Keep Scouting for Alfalfa Weevils

This week we received a report and picture confirmation of early-instar alfalfa weevil larvae in an alfalfa field. Although most alfalfa fields were treated for alfalfa weevils before the first cutting, those fields still need to be scouted.

It’s Time To Start Scouting for True Armyworm Caterpillars in Wheat

This week, we collected quite a few true armyworm moths from our traps around eastern South Dakota. That means that true armyworm caterpillars will probably be showing up soon. To play it safe, scouting should start this week to stay ahead of potential issues.

Tan grasshopper with light colored stripes on its back sitting on the soil surface.

Grasshoppers Are Causing Concerns in South Dakota Crops

In 2020, grasshopper populations were an issue in parts of central and western South Dakota. The populations this year are moving into crops earlier and appear to be as bad as the ones observed last year.

Three beetles. From left: Black colored blister beetle on a purple flower. Gray colored blister beetle on a green alfalfa stem. Orange-brown colored blister beetle feeding on a sunflower head.

Blister Beetles Showing up in Alfalfa Fields

Blister beetles are now active in South Dakota. Although the larvae of blister beetles can be beneficial by feeding on grasshopper eggs, the adults cause issues when large populations are present in alfalfa at the time of harvest.

White silken tube with dark colored ends on a light background.

What’s Leaving These White Skins on My Lawn?

There have been many reports by homeowners of birds pulling out white, cigarette-looking tubes from their lawns. These tubes are silken tunnel linings created by the cigarette paper webworm.

Orange and metallic green moth resting on a green leaf.

Squash Vine Borers Ramping up in South Dakota

Last week squash vine borer moths were observed in South Dakota. For this reason, it is important to scout for the moths as well as eggs on the stems of zucchini, squash, pumpkins and related produce.

Green soybean with wilting/dying soybean within the same row.

Soybean Gall Midge Larvae in South Dakota Soybean

Soybean gall midge larvae were observed in South Dakota soybean this week. Although insecticide applications haven’t been very effective at this stage, it is still important to scout fields and determine the location and extent of soybean gall midge infestations.

A brown soybean stem with three bright orange larva on it.

Soybean Gall Midge Larvae Observed in South Dakota

Soybean gall midge emergence continues to be slow in South Dakota. In the past week, two additional adults have been captured in South Dakota.