Pest Management of Argentine Ants (Hymenoptera: Formicidae)¹

Control of Argentine ants, Linepithema humile (Mayr), around structures in urban settings requires an extensive and thorough use of existing registered sprays and baits. Barrier sprays must be thoroughly applied at maximum label rates to prevent ants from accessing structures. Although insecticides with systemic activity such as imidacloprid and thiamethoxam may ultimately reduce homopteran food sources for L. humile, quantifying the impact of such reductions has been difficult. Applications of bifenthrin and deltamethrin granules provide short-term reductions. Most commercial baits available for L. humile are not readily consumed by foragers, or they provide too rapid kill of workers. Consequently, none of the baits are consistently effective. Potential new active ingredients for baits such as fipronil, imidacloprid, and thiamethoxam provide about 50% kill within 3 days and are readily accepted by foragers. These toxicants are extremely promising in liquid bait formulations. No single control strategy or treatment has been consistently effective.