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A vast, open rangeland with a few patches of weeds.

An identification guide to common Rangeland Insect Pests of South Dakota

The insects listed in this guide can be pests of rangeland in South Dakota. The best approach for preventing these pests from reaching damaging populations involves routine scouting.

A shiny caterpillar with a light brown head, dark brown body, and three yellow stripes down the length of its back.

Watch Corn for Bronzed Cutworm Activity

Bronzed cutworms are not a common pest of corn in South Dakota. However, they can become an issue when corn is planted into areas that were previously grassland. Like its name implies, bronze cutworms feed on corn above the soil surface, which often results in cutting or clipping.

Tick that is dark brown to black in color with a reddish-orange abdomen.

Protecting Yourself From Ticks

During wet springs, tick populations tend to thrive in South Dakota. These parasitic arthropods require blood to fulfill their nutritional needs and commonly use humans as a host. Some ticks can also carry bacterial diseases that are a threat to human health.

Image of western South Dakota where green triangles indicate areas with low grasshopper populations, orange squares indicate medium grasshopper populations, and red circles indicate high grasshopper populations that exceeded thresholds.

2019 South Dakota Grasshopper Forecast

The USDA Animal Plant Health Inspection Service conducts an annual survey to monitor grasshopper populations in Western South Dakota. In 2018, SDSU conducted a survey to monitor populations in Eastern South Dakota. These previous-year surveys can be used as a prediction tool for where grasshoppers may be an issue during the upcoming season.

Grassy pasture with a small hill of dirt in the foreground. There is green grass at the base of the mound.

Are Ant Mounds in Pastures Bad?

We often receive reports of large ant mounds in a pastures and rangeland. These mounds are the creation of thatching ants, which are common in South Dakota. Although these mounds are often considered a nuisance, the ants may play an important role as predators of potential pest insects.

A grub that has an orange colored head and legs and a white body with a dark grey tip at the end. The grub is laying on top of the soil.

2019 June Beetle Update

In the spring of 2016, we received reports of large populations of June beetles in Central South Dakota, which indicates the start of a new cycle for the grubs. Based on these reports, it is estimated that 2019 will be the big emergence year if the 2016 adults were successful and their grubs survived.

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.

A map of South Dakota with yellow and green circles indicating iverson risks at various locations throughout the state.

Use the SD Spray Tool for Inversion Detection and Weather for Pesticide Application

The SD Mesonet Spray Tool provides real-time weather data for pesticide applicators. This dedicated website for pesticide applicators uses the SD Mesonet weather data, which is updated every five minutes.

black angus cattle grazzing in pasture

South Dakota Grazing Management Practices: Current & Future

Grazing land occupies 54% of rural land and accounts for a key portion of land use in South Dakota. Many grassland problems can be avoided by using efficient grazing management practices.

open rangeland with smooth bromegrass growing throughout

Smooth Bromegrass Grazing Management

Smooth bromegrass is a cool-season introduced grass with an advanced root system that tolerates temperature extremes and drought exceptionally well.