Grasshoppers have been recognized as a periodic problem in Nebraska for many years. Pasture grasshopper species that are most damaging are found in areas with less than 30 inches of annual rainfall. Two-thirds of Western Nebraska fall into this rainfall category. With the occurrence of consecutive years of drought, grasshopper outbreaks are possible. The past several years southwestern, southcentral, and western Nebraska have experienced below normal precipitation. This type of weather pattern can play a large role in rangeland grasshopper outbreaks.
The 2025 Rangeland Grasshopper Hazard Map (Fig 1) indicates ten counties (red) in Nebraska that had fall adult grasshopper numbers averaging over 15 per square yard. These data are based on the 2024 adult survey, which is a good indicator of possible grasshopper issues for the summer of 2025.
Approximately 50 species of grasshoppers are found on rangeland in Nebraska; though, generally fewer than 10 species ever reach economic levels, accounting for 95 percent of the damage. Grasshoppers defoliate grass by direct feeding on leaf and stem tissue and by cutting off leaves or stems.
Life Cycle
The developmental stages of all grasshoppers include the egg, nymphal, and adult stages. Most species winter as eggs. Normally, grasshopper eggs will remain in the overwintering stage until the ground temperature reaches 50°to 55° Fahrenheit. Newly hatched grasshoppers look like miniature adults except they lack wings, and their sex organs are not developed. As young grasshoppers grow, they shed their skin (molt). Depending upon the species they might molt four to six times, with five molts being the average. The rate at which nymphs develop is influenced by temperature and food quality. Most species reach the adult stage, 30 to 50 days after hatching.
Impact
Grasshoppers consume up to 50% of their body weight every day in forage. Another way to look at it is an acre with 2.7 grasshoppers/yd2 equals 12,971 grasshoppers. An acre with 69.7 grasshoppers/yd2 equates to the consumption of forage by one cow per day.
Economic thresholds for grasshopper densities in rangeland vary from 8 to 40 grasshoppers per square yard. The thresholds are influenced by several factors, including the cost of control product, projected forage yield, and the value of forage considered for treatment.
Monitoring
As we move closer to late spring, livestock producers and landowners should visit their pasture sites and look for the possibility of small grasshoppers.
One of the better methods for determining grasshopper density is to count the number of grasshoppers using the square foot method. With this method sample at multiple sites about 50 to 75 feet apart. Select a point several feet away and visualize a one-foot square area around the point. Walk toward the point counting any grasshoppers you see in or jumping out of this area. Repeat 18 times, total the number of grasshoppers and divide by 2. The resulting number will be the number of grasshoppers per square yard.
A request for technical assistance to evaluate the need for grasshopper control in rangeland may be submitted to USDA-APHIS, by contacting David Nielsen at (402) 434-2348 or by email at David.Nielsen@usda.gov
Article by David Boxler, Nebraska Extension, Livestock Entomology Educator.
