Grasshoppers have the potential to cause significant harm to Wyoming’s rangeland and crops due to their voracious feeding habits. During outbreak years, adult grasshopper densities can exceed 30 insects per square yard, well beyond sustainable levels in most areas of the state.
In 1973 the Wyoming legislature identified grasshoppers as a designated pest under the state weed and pest law. This designation allows Weed and Pest Control Districts to assist landowners and federal land managers in their district with implementing landscape-scale grasshopper management programs using practices established by the University of Wyoming, College of Agriculture including the use of the Reduced Agent and Area Treatment strategy (RAATs). Weed and Pest Control Districts also work with USDA APHIS to monitor grasshopper outbreaks on local and state-wide levels.
USDA: Grasshopper Integrated Pest Management User Handbook
University of Wyoming: Grasshoppers
Grasshoppers of Wyoming and the West
MOUNTAIN PINE BEETLE
Although there are several native bark beetle species found in Wyoming, the Mountain Pine Beetle is the most widely recognized for its impacts. The beetles kill pine trees through larval feeding and by introducing blue stain fungus into the sapwood. In 2011, aerial surveys estimated that over 3.3 million acres of federally managed forests in Wyoming were affected by the Mountain pine beetle.
In 1973 the Wyoming legislature identified the Mountain Pine Beetle as a designated pest under the state weed and pest law. Weed and Pest Control Districts work with Wyoming State Forestry District offices and the timber industry to assist local landowners with programs varying from education to chemical cost-share or even to the hiring of sawyer crews.
USDA: Rocky Mountain Bark Beetle
The beet leafhopper, Circulifer tenellus, is the vector of curly top virus. The virus causes curling of beet leaves which later become brittle. This virus has the potential to cause severe economic losses when sugar beets are infected in epidemic proportions. The beet leafhopper over winters as an adult in rangeland and idle agricultural lands and migrates in the summer to susceptible crops. Both treatment of surrounding non-crop areas and the utilization of insecticide treated sugar beet seeds can assist with the management of the virus. Due to the potential economic loss, the 1973 Wyoming legislature listed the beet leafhopper as a state designated pest. Weed and Pest Control Districts can assist local landowners with IPM practices to help them minimize the impacts of the beet leafhopper and curly top virus.
The Mormon cricket, Anabrus simplex, is a large migrating insect in the katydid family (not a true cricket). During mass migrations, Mormon crickets can cause extensive damage to forage plants in crops and rangeland in their migration path. Mormon crickets feed voraciously on wheat, barley, alfalfa, sweetclover, truck crops, and garden vegetables. Because of their migratory habit, a single Mormon cricket spends only three or four days at a particular site, causing little damage in that short time. But migrating bands of nymphs or adults may completely destroy fields of sugar beets, small grains, and alfalfa. During the 1937 outbreak, Mormon crickets caused $383,000 of crop damage in Wyoming.
In 1973 the Wyoming legislature listed the Mormon cricket as a state designated pest. Weed and Pest Control Districts can assist local landowners with IPM practices to help them minimize the impacts of Mormon crickets on their crops during mass migration years.
BLACK-TAILED PRAIRIE DOG
Prairie dogs are burrowing rodents that can be found throughout the vast rangelands of Wyoming. Of the five species of prairie dogs, two species are known to exist in the state, the black-tailed prairie dog, Cynomys ludovicianus and the white-tailed prairie dog Cynomys leucurus. Both species can be destructive to agriculture and rangeland , however the majority of the issues in the state are associated with the black-tailed prairie dog in the central and eastern counties. Each prairie dog can consume up to two pounds of forage per month, reducing the forage available to other wildlife and livestock. Prairie dogs are carriers of sylvatic plague, an infectious disease caused by the bacterium that causes bubonic and pneumonic plague in humans. Under favorable conditions, prairie dog towns can become dense and naturally expand into areas that directly compete with agriculture, and their burrowing can be disruptive to irrigation and dangerous to livestock. Prairie dogs were initially identified as a nuisance rodent in Wyoming by the 1886 Territorial Legislature. In 1973 the Wyoming legislature identified the prairie dog as a designated pest under the current weed and pest law. The designation allows the county Weed and Pest Control Districts to work with local landowners in developing management programs that include cost-share agreements.
Ground squirrels are members of the squirrel family of rodents and generally live on or in the ground. Several different species of ground squirrels can be found in Wyoming, however the Wyoming ground squirrel Urocitellus elegans, formerly called the Richardson’s ground squirrel, is associated with issues in the state.
Ground squirrels can compete with livestock for forage and can destroy food crops. Their burrows can damage ornamental landscaping, hay fields, golf courses and cemeteries. Unlike prairie dog mounds that are dome or crater shaped, ground squirrel holes are fanned out and typically level with the surrounding landscape. The Wyoming ground squirrel can often be confused with the black-tailed prairie dog, but unlike the black-tailed prairie dog, the Wyoming ground squirrel hibernates over winter.
Issues with ground squirrels in the state have been identified as far back as 1893 when the University of Wyoming reported in 1892 their barley harvest at the Laramie Experiment Farm was so badly damaged by ground squirrels that in some instances the yield was less than the amount of seed sown.
Ground squirrels were initially identified as a nuisance rodent in Wyoming by the 1886 Territorial Legislature. In 1973 the Wyoming legislature identified the ground squirrel as a designated pest under the current weed and pest law. The designation allows the county Weed and Pest Control Districts to work with local landowners to develop management programs that may include cost-share agreements.
2019 State Designated Species 2019 County Declared Species List