Description
Grasshoppers are a visible, frustrating pest of rangeland, field crops, and gardens. Grasshopper outbreaks occasionally build up in numbers and cause problems over hundreds of thousands of acres of rangeland, pasture, and row-crops in Oklahoma. It is a challenge to manage grasshoppers because it is difficult to predict if, and when, they will become a problem. Often large numbers of grasshopper nymphs hatch in an area, but as time, weather, and natural enemies take their toll; they fail to develop into a severe problem.
Grasshoppers can damage crops anywhere in Oklahoma, but are more likely to become a threat in areas that receive less than 30 inches of annual rainfall (see Figure 1). Because Oklahoma is subject to periods of drought, other parts of the state may fall below that 30-inch threshold for several years. In addition, the timing of rainfall can substantially lower survival of eggs and nymphs in a given area. Thus, we sometimes see grasshoppers become a problem in isolated pockets across the state for a few years and then subside.
Over 130 species of grasshoppers reside in Oklahoma. Most never attain pest status because they are either not large enough or do not become numerous enough. In rangeland and pastures, grasshopper problems develop from a “complex” of species that tend to occur together and build in numbers large enough to cause damage. The most economically important species are the two-striped slant-face, migratory, two-striped, redlegged, differential, and Packard grasshoppers.
