Grasshoppers a Threat in Western States

Western rangelands could see serious grasshopper infestations this year. That is based on what occurred last fall as adult grasshoppers caused economic damage across Wyoming, parts of Montana and other states. Last fall, U.S. Department of Agriculture's (USDA) Animal and Plant Health Inspection Service conducted counts of adult populations, which serve as a predictor of eggs laid.

Farmers and ranchers in these high-risk areas should be prepared to monitor the build-up of grasshopper densities during the hatching and early development periods from mid-May through June, said Bob Wright, entomologist in the University of Nebraska - Lincoln's Institute of Agriculture and Natural Resources.

The actual impact of grasshoppers will be determined largely by two factors said Wright:

Food availability - Immediately after grasshoppers hatch from their eggs, they have few fat reserves and are vulnerable to cool, wet weather. If they cannot feed readily during these early stages, high mortality will result. Since grasshoppers hatch over an extended period, only some of the hatch may be affected; however, this mortality can be significant enough to reduce heavy populations below threshold levels in many areas.

Rainfall - In areas with ample rainfall, fewer problems will materialize because of the increased grass growth, resulting in less pressure for grass. Healthier, more vigorous grass growth equals fewer grasshopper problems.

If grasshopper populations persist through the early hatching period and dry conditions limit grass growth, there likely will be widespread areas with serious grasshopper infestations, and control may need to be considered, said Jeff Bradshaw, entomologist at University of Nebraska's Panhandle Research and Extension Center at Scottsbluff.

Reprinted in part from AgWeb.com