Pathogenicity of Beauveria bassiana ANU1 to the red imported fire ant, Solenopsis invicta workers in Korea

Abstract

• B. bassiana ANU1 (Bb ANU1) showed the pathogenicity to S. invicta workers. • LC 50 s were calculated as major (3.9 × 10 3 ) and minor (4.6 × 10 3 ) at 7 DAT. • Bb ANU1 showed virulence to workers at low temperature, 10 °C. The red imported fire ant (RIFA), Solenopsis invicta , is one of the globalized invasive pests. This study focused on pathogenicity and virulence of entomopathogenic fungi as one of the biological control agents to RIFA workers under different temperatures. The fungal pathogen, Beauveria bassiana ANU1 was isolated from Korea in 2015 and showed the pathogenicity to RIFA workers. A conidial suspension (1 × 10 7 conidia/ml) induced a low mortality from day 2 after treatment and reached to 100% mortality at day 7 and day 8 after treatment for major and minor workers, respectively. The median lethal concentrations of B. bassiana ANU1 were calculated as 3.9 × 10 3 for major and 4.6 × 10 3 for minor workers at day 7 after treatment. Low temperatures decreased a virulence of B. bassiana ANU1 (1 × 10 7 conidia/ml) to RIFA and showed mortality of 26.6% for major and 20% for minor workers. Based on bioassay results, this study provides one of possibilities of effective and successful strategy for controlling RIFA by entomopathogenic fungi.