Precision Targeting: Controlling Urban Pest Ants Using Horizontal Insecticide Transfer.

The goal of the current study was to provide the first experimental examination of horizontal transfer under field conditions. The specific objective was to investigate horizontal transfer of fipronil in field colonies of black carpenter ants, Camponotus pennsylvanicus. Laboratory experiments demonstrated that fipronil is effectively transferred from treated donors to untreated recipients and causes significant secondary mortality. Fipronil was effectively vectored to untreated ants from donors exposed via residual and direct spray applications and 100% mortality was achieved with both exposure routes. Furthermore, horizontal transfer continued beyond secondary mortality and resulted in significant tertiary mortality which has not been previously demonstrated in ants. Field experiments utilized a novel, three-step control method consisting of trap-treat-release and demonstrated that fipronil is effectively transferred when foraging workers are trapped, treated, and subsequently released back into their colonies. The current study is the first field demonstration of the importance of horizontal transfer for the control of pest ants.