Content by Adam Varenhorst

Small shiny fly larvae with black heads on a brown plant root.

Fungus Gnats Affecting Soybean Emergence

We have recently received a report of a maggot attacking soybean seedlings. During most years, we would immediately expect this to be a case of seedcorn maggots, but it was fungus gnat larvae.

Springtails Are Active in South Dakota

Recent reports of seemingly millions of very small insects moving around on driveways and around homes was the result of a springtail population boom. Springtails typically become a nuisance during drought conditions or saturating rains.

Dense swarm of mosquitoes in the evening sky

West Nile Virus Update: July 2, 2026

On June 15, 2026, the South Dakota Department of Health released a press release that the first West Nile Virus positive pool of mosquitos was detected in Brown County. Although much of the state is still experiencing drought, recent heavy rains will promote already active mosquito populations.

Small shiny black beetle with two light tan stripes on elytra.

Alfalfa Should Be Scouted for Presence of the Palestriped Flea Beetle

Palestriped flea beetles have recently been observed in alfalfa fields in South Dakota. Large populations of palestriped flea beetles can cause rapid defoliation and stunt seedling alfalfa.

Base of soybean stem with orange larvae present under the epidermis.

Soybean Gall Midge Larvae Active in South Dakota

Soybean gall midge larvae are active in soybean in southeastern South Dakota. The first symptoms of an infestation during this part of the season vary based on the size of the population within the plant.

Three bean leaf beetles. From Left: Brown beetle with black spots on a green leaf. Yellow beetle with black spots on a green leaf. Red beetle with black spots on a green leaf.

Bean Leaf Beetles, a Vector of Bean Pod Mottle Virus, May Be Active in Soybean

Although we are predicting low overwintering survival of bean leaf beetles this year in South Dakota, scouting for this pest should still be conducted, as every year we still observe populations in soybean.

Soybean plants cut by cutworm caterpillars

Keep an Eye Out for Cut Soybean Plants: A Sign of Dingy Cutworm Presence

Dingy cutworms have been observed in South Dakota no-till soybean fields. Their activity will likely continue for at least another couple of weeks.

Green wheat with small mites present near the tips of the leaves.

Drought Stress in Wheat Leads to Increased Banks Grass Mite Activity

There have been reports of large populations of Banks grass mites in South Dakota wheat fields. Banks grass mite populations are more successful during hot, dry weather that also increases the susceptibility of wheat due to it being drought stressed.

Green leaf infested by small insects that are brown and black.

Early Season Soybean Infested by False Chinch Bug

At the end of last week, we received several reports of false chinch bugs attacking seedling to early vegetative stage soybean in South Dakota. In these cases very large populations were present on seedling soybeans as well as the ground around them.

Aerial view of the SDSU Northeast Research Farm.

Jul 23

Northeast Research Farm Tour

Attend the annual Northeast Research Farm Tour on Thursday, July 23, 2026, from 4:00 p.m. CDT to dusk at the Northeast Research Farm (15710 455th Ave. South Shore, SD 57263). The farm is located on the junction of State Highway 20 and Codington County Highway 11, or 2.5 miles west of Exit 193 on I-29.