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Content by Philip Rozeboom

Left Mosquito specimen with dark coloration. Right: Mosquito specimen with white band on its proboscis.

Mosquitos to Watch for in South Dakota

After many areas in South Dakota experienced heavy rainfalls, mosquitos are now a major issue. Learn which species are most common throughout the state and which carry the highest risk for West Nile Virus.

A hand holding a brownish gray moth with a valley of green grass and trees in the background.

Army Cutworm Migration Swarms Detected in Western South Dakota

Mass populations of army cutworm moths are being reported to entomologists at South Dakota State University. Thus far, these migratory swarms have only been observed in far western South Dakota, particularly within the Black Hills.

Western bean cutworm caterpillar on corn.

Western Bean Cutworms Detected in South Dakota Corn

Western bean cutworm caterpillars have been reported in South Dakota corn. This pest can cause yield loss by feeding on the tassels, silks, and ears. In addition, ear feeding activities increase the likelihood of secondary diseases and mold growth on the ear.

Green plant with evidence of honeydew and an aphid colony.

Aphids Infesting Corn in South Dakota

Aphid populations are taking off in some southeastern South Dakota corn fields. The two aphid species that are commonly observed in corn include the corn leaf aphid and the bird cherry oat aphid.

Red-brown colored weevil with bent antennae originating on the elongated mouthparts.

Is it Time to Spray Red Sunflower Seed Weevils?

Red sunflower seed weevil adult activity is well underway on sunflowers in South Dakota. Even though the red sunflower seed weevil numbers are down, we are still observing populations in South Dakota that are above threshold.

A green field bindweed with a white flower at top.

In a Bind With Field Bindweed?

It’s August and field bindweed, one of our most-persistent perennial weeds, is flowering. Although field bindweed is not statewide noxious, it’s locally noxious in Bennett, Bon Homme, Clarke, Lake, Stanley, and Yankton counties.

Wheat plants infected with wheat streak mosaic virus.

Volunteer Wheat and Kochia Management With Herbicides Will Likely Require Two Passes

Wheat curl mites, which carry wheat streak mosaic virus, use volunteer wheat and grass weeds as secondary hosts to infest recently planted winter wheat crops. Therefore, effective management of these plants before winter wheat planting is critical.

Combine harvesting wheat.

Weed Management After Wheat Harvest

Most of the winter wheat has been harvested in South Dakota and spring wheat harvest is underway. While the growing season is over for the wheat, post-harvest weed management is important to minimize the amount of weeds that are present in the spring

A soybean leaf infested with numerous soybean aphids.

Soybean Aphids Exceeding Thresholds in Some Parts of South Dakota

There have been a few fields this week that were infested with soybean aphids that are getting closer to threshold. We have also received reports of insecticides being applied to manage soybean aphids in South Dakota.

Green Canada thistle with whitened leaves at the top. Various green plants throughout.

White Thistle Disease: Biological management at work

White thistle disease can be seen among many Canada thistle plants throughout South Dakota this growing season. Plants infected with the disease exhibit significant reductions in both growth and seed head compared with non-infected plants.