Tunneling responses of mole crickets (Orthoptera: Gryllotalpidae) to the entomopathogenic fungus, Beauveria bassiana

Abstract

Greenhouse studies of mole cricket tunneling architecture were conducted with adult southern, Scapteriscus borellii Giglio-Tos and tawny, Scapteriscus vicinus Scudder, mole crickets exposed to Beauveria bassiana (Balsamo) Vuillemin. Three different strains of B. bassiana as well as the commercially available insecticide Talstar (bifenthrin) were evaluated for avoidance behaviors by examining tunneling characteristics. Each treated container was inspected 24 h after treatment for specific tunneling behaviors in association with the presence of a control agent and the cricket's response to the conidia or chemical. One of the B. bassiana strains tested, DB-2, caused changes in mole cricket behavior, including significantly less new surface tunneling, fewer vertical tunnels descending into the soil, less tunneling along the perimeter of the containers, and significantly more occurrences of the crickets remaining in an area that reduced exposure to the conidia. Two of the other treatments, strain 10-22 and Talstar, produced some of these same altered behaviors in mole crickets. Mole crickets exposed to a third strain of B. bassiana, BotaniGard, as well as two carrier formulations did not exhibit these same levels of avoidance. These observations indicate that the presence of environmentally "friendly" control agents, such as entomogenous fungi, may affect pest behavior, and strain selection may be critical to eliminate detection and avoidance by the target insect.