Comparison of Three Traps Used for Pocket Gopher Management (Thomomys Bottae) in Alfalfa Fields

INTRODUCTION Valley pocket gophers (Thomomys bottae) are a common agricultural pest in many areas of Utah, Nevada and California. Pocket gophers predominantly eat roots, although they will pull vegetation into their burrows, and eat plants immediately adjacent to their burrow holes. Unlike other fossorial rodents (rodents that live under the ground), pocket gophers are active year round throughout much of their distribution. Activity patterns vary with climate; however, valley pocket gophers generally begin breeding activities in late March – early April, with young born in late May – June. Juveniles will begin dispersal in August. Their activity patterns and diet causes agricultural conflicts wherever the two overlap. In a survey conducted by Messmer and Schroeder (1996), agricultural producers in Utah reported that pocket gophers were the most abundant threats to production, reported present on 124 (82.7%) of the farms surveyed. In a landscape of native arid vegetation such as in the sagebrush steppe in the Great Basin of the Intermountain west, crops with large tap roots (e.g., alfalfa, Medicago sativa), are an attractant for pocket gophers. The alfalfa growing season is longer than many other crops in Utah; the first cutting can begin in the last week of May and the last cutting usually occurs in October. This growing season encompasses the breeding, rearing, and dispersal seasons of valley pocket gophers. Thus farmers require options for pocket gopher control to protect their crops throughout the season; often an integrated management approach is the most effective. To increase effectiveness, removing pocket gophers via lethal control during the breeding season is often preferred because this removes the adult population and reduces the potential for juveniles during that season.