Enhanced activity of Beauveria bassiana to red imported fire ant workers (Hymenoptera: Formicidae) infected with Thelohania solenopsae

摘要

A range of concentrations of Beauveria bassiana (Balsamo) Vuillemin conidia was tested against red imported fire ant, Solenopsis invicta Buren, workers from colonies infected with the microsporidian, Thelohania solenopsae Knell, Allen, and Hazard, and on workers from healthy colonies. Median lethal concentrations (LC_(50)) of B. bassiana in healthy and microsporidian-infected colonies showed that fire ants from infected colonies were more susceptible to B. bassiana infection than ants from healthy colonies. The LC_(50) of B. bassiana in microsporidian-infected workers was 4.5X less than that of healthy colonies. Mortality of ants from T. solenopsae-infected colonies that were treated with 9.66 x 10~6 B. bassiana colony forming units per cm~2 was subadditive compared to either pathogen alone.