Figure 1. Estimated grasshopper densities per square yard (as of 7/7/11) as determined by the USDA-APHIS “Rangeland Grasshopper and Mormon Cricket Suppression Program.”

July 7, 2011

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Figure 2. A cast skin (or exuvium) of a grasshopper nymph. Figure 3. A young nymph of the differential grasshopper, Melanoplus differentialis; primarily a pest of field crops.

Much of western Nebraska escaped a large potential for “spring feeding” grasshoppers; however, the “summer feeding” grasshoppers are coming on strong in parts of the Panhandle.

As of July 7 (Figure 1), Banner, Blaine, Box Butte, Cherry, Dawes, Dawson, Garden, Loup, Scotts Bluff, Sheridan, and Sioux counties all had at least one grasshopper sample that exceeded an average of 20 grasshoppers per square yard. These numbers may be a conservative estimate for some locations as, for example, new grasshoppers nymphs in many locations in Scotts Bluff County have exceed 20 grasshoppers per square yard just over the weekend. Scouting grassy areas, I could easily find evidence of much grasshopper development (Figure 2) and “summer feeding” grasshopper nymphs (Figure 3).

We are likely moving out of the period when rangeland would be most affected. Range is in good health due to ample precipitation and low spring grasshopper numbers. That said, there still could be an impact on rangeland quality should the weather turn dry.

Just as importantly, these high grasshopper numbers in parts of western Nebraska could indicate an increasing risk to field crops. A number of Panhandle fields had to be replanted this year so it will be particularly important to scout field edges and pivot corners for grasshoppers. As vegetation in these areas dries down, grasshoppers could move into crops and cause damage. This could be especially problematic as we move into wheat planting in a few weeks.

More Information

For information on identification, scouting, and management options, check out the UNL “Grasshoppers of Nebraska” page at http://entomology.unl.edu/grasshoppers/

Jeff Bradshaw
UNL Extension Entomologist, Panhandle REC, Scottsbluff