By Scout Nelson
Each year, USDA-APHIS surveys adult grasshopper populations in the fall to estimate the risk for the following year. Based on its 2024 surveys, the risk of grasshopper infestation in Nebraska rangelands for 2025 is predicted to be moderate to severe, with the western half of the state facing a slightly higher risk. The surveys indicate that much of the western United States will see moderate grasshopper numbers in 2025.
Grasshopper populations are influenced by environmental conditions, but species vary in their responses to factors such as precipitation, plant communities, soil types, and microclimates.
A wet spring with rainfall at the time of grasshopper hatching and development (mid-May to June) can help improve rangeland forage quality and reduce the damage caused by infestations. However, current weather forecasts suggest warm, dry conditions, which could increase the likelihood of grasshopper injury to crops and rangeland.
Despite these forecasts, high grasshopper densities can still occur in spotty areas, even during low-risk years. Therefore, ranchers and range managers should stay vigilant and monitor grasshopper densities, particularly during the hatching period.
It is recommended to begin scouting fields and field edges starting in late April or early May when grasshoppers are still in the nymph stage, as they are easier to control at this stage.
To scout for grasshoppers, the square foot method is effective. Select a random area several feet away, visualize a one square-foot area, and count the number of grasshoppers jumping in or out of this area. Repeat this 18 times and divide the total count by two to get the number of grasshoppers per square yard.
Economic thresholds for grasshopper control range from eight to 40 grasshoppers per square yard. Control measures are most effective before grasshoppers reach the adult stage. For more information on treatment options, consult Crop Watch.
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Categories: Nebraska, Weather