Grasshoppers Continue to Be an Issue During 2023

Written collaboratively by Adam Varenhorst, Philip Rozeboom, Patrick Wagner, and Brad McManus.

Originally Submitted: June 26, 2023

As drought conditions in South Dakota increase, the risk of grasshopper issues in those areas also increases (Figure 1). We have received numerous reports and have also observed very large populations of grasshopper nymphs throughout much of eastern South Dakota in June.

Map of South Dakota with varying colors indicating the level of drought that is being experienced. For a detailed description of this graphic and data set, please call SDSU Extension at 605-688-6729.
Figure 1. U.S. Drought Monitor for South Dakota. Updated June 20, 2023. Courtesy: U.S. Drought Monitor

Although our recent observations are that most of these populations are still in their developmental stages, current weather conditions may decrease the time it takes the grasshoppers to reach their adult stage. The most-observed pest species typically take 40 to 60 days after hatching to reach their adult stage. However, when temperatures remain at or around 85 degrees Fahrenheit, they can reach adulthood in approximately 30 days.

Before management action is taken, it is important to determine what stage the observed grasshoppers are at. Grasshopper nymphs are generally much easier to manage and can also be treated with insect growth regulators to arrest their development. However, these products do not affect grasshopper adults. Grasshopper adults also require higher rates of insecticide for effective management.

Grasshopper Stages

Nymphs

Mottled brown grasshopper nymph sitting on a green leaf. Wing pads are easily observed in the image.
Figure 2. Redlegged grasshopper nymph. Courtesy: Joseph Berger, Bugwood.org
 

Grasshopper nymphs will vary in size and will have wing pads (incomplete wings) (Figure 2). The coloration of the grasshopper nymphs will also vary from their adult stages.

Adults

Grasshopper with red tibia and wings.
Figure 3. Redlegged grasshopper adult. Courtesy: Joseph Berger, Bugwood.org
 

In contrast, the adult grasshoppers will be larger and have complete wings that nearly reach or extend beyond the end of the abdomen depending on gender and species (Figure 3). The adult grasshoppers will also have the coloration and markings that are used for identification.

Management Recommendations

For scouting recommendations and grasshopper thresholds please view our article, Large Grasshopper Populations Detected in South Dakota.

Related Topics

Corn Insects, Soybean Insects, Wheat Insects, Forage, Range, Grassland, Pasture, Drought: Range and Land Management, Drought: Crops

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