Effectiveness of the Insect Growth Regulator Pyriproxyfen Against the Red Imported Fire Ant (Hymenoptera: Formicidae)

The juvenoid pyriproxyfen (2-[l-Methyl-2-(4-phenoxyphenoxy) ethoxy] pyridine caused 80–85% reductions in the colony size index of laboratory colonies of the red imported fire ant, Solenopsis invicta Buren, within four weeks after treatment. All treated colonies continued to decline in size and died within 6–7 months after treatment. Corn grit-soybean oil baits contianing pyriproxyfen were as effective in four field tests as Logic, a JH-based bait widely used for fire ant control. The baits were slightly more effective in spring-summer than in fall, producing population index reductions of 91–97% and 72–88% respectively at 13 weeks after treatment.