Grasshopper
Grasshoppers are among the most significant insect pests affecting rangeland and agricultural production in Wyoming. Numerous species occur throughout the state, including several in the genera Melanoplus and Camnula pellucida, which are commonly associated with damaging outbreaks. These insects can cause substantial losses because of their voracious feeding habits, consuming grasses, forbs, and many cultivated crops.
During outbreak years, grasshopper populations can increase rapidly when warm, dry conditions favor egg survival and nymph development. In severe infestations, adult densities may exceed 30 grasshoppers per square yard, a level far beyond what most rangelands can sustain. At these densities, grasshoppers can strip vegetation, reduce forage available to livestock and wildlife, damage crops, and hinder rangeland recovery following drought or heavy grazing.
Grasshopper management in Wyoming focuses on early detection and landscape-scale control to prevent widespread economic damage. In recognition of the threat posed by large infestations, the 1973 Wyoming Legislature designated grasshoppers as a state pest under the state weed and pest law. This designation allows local Wyoming Weed and Pest Council districts and county Weed and Pest Control Districts to assist landowners and federal land managers in implementing coordinated grasshopper management programs.
Control efforts often follow recommendations developed by the University of Wyoming College of Agriculture, Life Sciences, and Natural Resources, including the Reduced Agent and Area Treatment Strategy (RAATs). RAATs is an integrated pest management approach that applies reduced insecticide rates in alternating treated and untreated swaths, allowing natural predators and untreated areas to help suppress populations while significantly reducing treatment costs and environmental impacts.
In addition to treatment programs, Weed and Pest Control Districts work closely with the USDA Animal and Plant Health Inspection Service to monitor grasshopper populations and forecast outbreaks at both local and statewide levels. These monitoring efforts help guide timely management decisions and protect Wyoming’s rangelands and agricultural resources from severe grasshopper damage.
