Amdro (0.88% hydramethylnon) eliminated Pheidole megacephala (F.) from infested pineapple fields within 1 wk. Reinfestation occurred by budding from established colonies along field perimeters. Solitary alate queens were not able to establish colonies within fields without ants. Logic (1% fenoxycarb) significantly reduced the number of foragers but did not eliminate ants from pineapple fields. P. megacephala eventually recovered from the Logic treatment because the 1% formulated commercial bait was partially repellent. Logic acted as an insect growth regulator and caused a caste shift in P. megacephala colonies. Treated colonies began producing males 11 wk after treatment compared with the complete lack of males in control plots. Production of worker pupae decreased significantly in colonies treated with Logic 11 wk after treatment.