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Soybean Insects

All Soybean Insects Content

Adult twospotted spider mites crawling on webbing that is attached to a leaf

Two-Spotted Spider Mite Populations Reaching Threshold

Drought conditions have continued and worsened in much of South Dakota during this season. As a result, two-spotted spider mite populations have been present in most fields and have recently had large population growth in soybean fields throughout the state.

Cream mite on a green-colored caterpillar.

Straw Itch Mites

Straw itch mites, also known as hay mites or grain mites, can be a major problem when present in hay or grain. The best way to avoid a straw itch mite infestation is to keep commodities at low moisture levels and bale straw when it is thoroughly dry.

Green soybean leaf with small holes near the center and edges.

Redheaded Flea Beetles Active in Soybean

Redheaded flea beetles are active in soybean. Although they haven’t caused significant defoliation yet, their activity should be monitored.

Green caterpillar with a dark brown head.

Obliquebanded Leafrollers Active in South Dakota Soybean

If you’ve observed rolled soybean leaves that are held together by webbing, don’t immediately think thistle caterpillar. The obliquebanded leafroller caterpillar will roll soybean leaves and hold the leaf in place with silken webbing.

Small, green teardrop shaped insects on a green, soybean stem with pink flower.

Soybean Aphids Spotted in South Dakota

Soybean aphid populations have been observed in South Dakota. Although these populations are still very small, it is a good reminder that soybean aphid scouting should occur throughout the growing season to prevent population outbreaks and yield loss.

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.

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.

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.

White and red caterpillar feeding within silken hideout on green soybean leaf.

Thistle Caterpillars Observed on Canada Thistle

Although thistle caterpillars are normally first observed in July or August, it is possible for them to appear earlier if weather conditions are favorable. While these caterpillars are generally not present in high numbers, they can cause severe defoliation.