Observations on the Desert Grasshopper, Trimerotropis pallidipennis pallidipennis, in Arizona

Abstract

Between 1936 and 1959 this was one of the most widely distributed grasshopper species in Arizona, both as to location and type of habitat. Populations averaged higher at moderate than at very low or very high elevations. The highest and most extensive infestations occurred in 1941 and 1958, mainly on nonirrigated desert land, in south-central Arizona following continuous fall-winter-spring periods when precipitation and the condition of desert vegetation were much above normal. Trimerotropis pallidipennis often migrated into cultivated land and caused damage to crops. Severe damage to seedling cotton in Pinal and Maricopa Counties occurred in 1958. It has a spring generation throughout its range in Arizona, and usually at least one additional generation at elevations below 5,000 feet. Desert populations were reduced 74% in 1 day and 86% in 6 to 7 days by an aldrin spray applied by aircraft in the spring of 1958.