Comparative Toxicity and Efficacy of Selected Insecticides in Field and Greenhouse Assays Against Tawny and Southern Mole Crickets (Orthoptera: Gryllotalpidae)

The toxicity of thiamethoxam against nymphs and adults of the tawny mole cricket, Scaptericus vicinus Scudder, and the southern mole cricket, S. borellii Giglio-Tos, was evaluated in the field and greenhouse. Thiamethoxam demonstrated varying levels of mole cricket control in the field studies. The performance of the insecticide appeared to be related to the application timing and formulation. Applications made in late June 1998 provided the best mole cricket control compared to the other two field studies. The LC₅₀ and LC₉₀ values of thiamethoxam against adult southern mole crickets were 1,816 and 9,978 ppm, respectively, using a greenhouse bioassay technique. Another greenhouse study indicated that thiamethoxam at application rates ranging from 154 to 616 g (ai)/ha did not provide acceptable control against medium sized nymphs (third to six instars) of tawny and southern mole crickets. An additional study with fipronil, bifenthrin, and deltamethrin compared mortality of the two species of mole crickets in greenhouse bioassays. In these assays, all insecticides resulted in different levels of mole cricket mortality between the two species. The use of bifenthrin resulted in significantly higher mortality of tawny than southern mole crickets.