Inconsistencies in the Use of Baits in Field Trials and Comparison To Laboratory Trials with Carpenter Ants (Hymenoptera: Formicidae)

Abstract:
Baiting offers an integral tool in the management of ants. Baiting trials with Camponotus modoc were successful in 55% of field trials with two granular, three gel, and two containerized baits in 2005-2007. Results with two granular, three gel, and four containerized baits in laboratory trials yielded over 95% mortality. Investigations in laboratory to determine inconsistencies in efficacy between trials using baits in the laboratory and field indicate (1) trials using baits only produce higher mortality than choice tests and (2) baits had varied results in trials conducted in July compared to trials in September. In these trials indoxacarb gel showed a decrease in activity; thiamethoxam gel, fipronil gel, and hydramethylonon granules showed an increase in activity; and no changes were observed with indoxacarb or fipronil containerized baits. Exposure of baits to sun, shade, moist, and dry conditions for 10 days before offering baits to ants demonstrated various results. The age factor produced lower mortality in gel baits and abamectin containerized bait compared to granular baits and containerized fipronil and indoxacarb. Consideration of these factors helps to explain bait failures in the field that may result from a number of conditions; however, the overall efficacy of baiting remains an effective management tool.