Comparison of the Control of Monogynous and Polygynous Forms of the Red Imported Fire Ant (Hymenoptera: Formicidae) with a Chlorpyrifos Mound Drench²

Single (monogynous) and multiple (polygynous) queen mounds of the red imported fire ant, Solenopsis invicta Buren, were treated according to label directions with individual mound drenches containing chlorpyrifos. Reduction of marked 30 mound sets and mound densities per unit area were monitored. Treated polygynous mounds were rendered inactive as easily as monogynous mounds. Percent reduction of polygynous mound densities was initially greater but mound reinfestation after approximately 10 weeks occurred at a higher rate for the polygynous ant. The higher mound density may be due to the survival of satelite mounds. Further, the density of polygynous mounds remained numerically higher than that of the monogynous mounds throughout the study period. In effect, more labor and insecticide was required to treat polygynous populations, because of higher initial mound densities.