EFFICACY of DIFFERENT BAITING MATRICES as TOOLS in the MANAGEMENT of CARPENTER ANTS (HYMENOPTERA: FORMICIDAE)

Abstract:
Carpenter ants, Camponotusspp., are major structural pests as well as nuisance pests in northern areas of the United States, southern Canada, and northern Europe. Management tools have included cultural controls to modify habitats and foraging, dust applications to wall voids, perimeter sprays, baiting, and combinations of these approaches. Comparisons of liquid, gel, and granular formulations were made at 87 field sites with infestations of C. modoc or C. vicinus. Toxicants in these tests included boric acid, avermectin, hydramethylnon, and fipronil. Foraging sites and trails were utilized during the foraging season for bait placement. Parameters for assessing control included observation of foragers, homeowner observations, and a final inspection the following spring. Efficacy of baits was investigated over five years and found to have 77% to 90% control. Liquids with boric acid required an average of 11.1 weeks for control, and hydramethylnon granules required 10 weeks. Both achieved 100% control. Fipronil granules had a 92% control in an average of 5.9 weeks, but the avermectin granules did not achieve control. Fipronil gel had a 76% control in 6.6 weeks. The results were highly variable because of differences in sites and in competition with natural foods. Granular baits were demonstrated to be effective in controlling carpenter ants in a reduced amount of time when the bait was competitive with natural foraging sources.