Conidial Powder Research Articles

Field Applications of Beauveria bassiana for Control of the Red Imported Fire Ant (Hymenoptera: Formicidae)

A Beauveria bassiana (Balsamo) Vuillemin isolate (Bb447), recovered from the red imported fire ant, Solenopsis invicta Buren, in Brazil was applied to fire ant mounds in Florida pastures. Rice with Bb447 applied to the tops of mounds resulted in a maximum infection of 55% of the live ants sampled; 70% of the treated mounds remained active or formed active new mounds within 8 wk. Injections of conidial powder formulations of Bb447 in late fall and early summer resulted in peak infections of 60 and 52% of live ants sampled, respectively. All of the injected mounds remained active or formed active new mounds within 8 wk after treatment. Injection of Bb447 mixed with a hydrophobic silica carrier resulted in a 52% reduction in active mounds. Injection of the silica carrier alone resulted in a 41% reduction. Foraging by the red imported fire ant was reduced significantly in areas within which mounds were injected with fungal formulations, whereas foraging by other ant species increased in these areas.