Field evaluation of two microsporidian pathogens, an entomopathogenic nematode, and carbaryl for suppression of the Mormon cricket, Anabrus simplex Hald. (Orthoptera: Tettigoniidae)

Abstract

Abstract In field enclosures, the microsporidium, Vairimorpha sp., produced significant reductions in survival (>60%) of Mormon crickets treated as first to third instars with bran bait (1012 spores/kg). This pathogen offers promise as a biological control agent for Mormon crickets. Reductions in survival attributable to Vairimorpha became statistically significant only after accounting for differential predation among treatment groups by the ant Formica criniventris Wheeler and Vesper sparrows. Nosema locustae Canning did not infect Mormon crickets or significantly reduce survival, despite high spore concentrations (1012 spores/kg) in the bran bait and cannot contribute to Mormon cricket management. The nematode Steinernema carpocapsae (Weiser) failed to infect or to reduce survival of Mormon crickets. Low palatability of nematode bait capsules contributed to the lack of pathogenic effects. Carbaryl bait, highly effective in reducing cricket density, can be applied at low rates of active ingredient per area for cricket suppression on rangeland or for immediate protection of crop fields.