Red Imported Fire Ant (Hymenoptera: Formicidae) Control in Nursery Pots Treated with Beauveria bassiana and Bifenthrin

Beauveria bassiana (Balsamo) Vuillemin GHA strain was tested alone and in combination with different rates of bifenthrin for control of red imported fire ant, Solenopsis invicta Buren, in potted nursery medium. The fungus killed fire ant workers in the potting medium, but was not effective at eliminating infestations in all containers. Bifenthrin at a rate of 1.18 kg Talstar™ (nursery granular, 0.2% Al) per m³ soil alone performed better than B. bassiana alone; however, bifenthrin was also inconsistent in eliminating fire ants from all pots over the 4 yrs of the study. When B. bassiana was combined with reduced rates (1/4 and 1/2) of bifenthrin in 2001, infestations were eliminated from treated pots within 96 h each time workers were added to the pots for the 7-wk test period. The number of infested bifenthrin + B. bassiana-treated pots was significantly lower than the number of infested untreated pots on all 19 sampling dates in 2001. Use of bifenthrin + B. bassiana was as effective or more effective than use of bifenthrin alone and could save growers as much as 15 to 40%.