Efficacy of bifenthrin treatment zones against red imported fire ant

Exclusion of ants, particularly red imported fire ant, Solenopsis invicta (Buren), from homes, nursing facilities, hospitals, and electrical housings is an important strategy in urban and rural pest control. We conducted a laboratory bioassay to determine the repellency of granular bifenthrin (Talstar: rate 2.087 kg of formulated product/92.88 m2 or 4.6 lb formulated product/1000 feet2 or 4.2 g active ingredient/92.88 m2) to S. invicta foragers. In the field, we compared the efficacy of three widths (0.3, 2.0, and 3.0 m) of granular bifenthrin-treated zones at the rate 2.087 kg of formulated product/92.88 m2 and investigated the survival of individual ants successfully crossing the respective zones. Granular bifenthrin was nonrepellent to fire ant foragers in the laboratory. The 2.0- and 3.0-m treatment zones provided 100% protection for 7 wk after treatment and provided a reduction in the number of ants breaching the treated zone compared with the control for the remaining 9 wk of the study. This level of control may be tolerable for homeowners and is, therefore, considered an effective treatment for 15 wk after treatment. Hospitals, nursing homes, and electrical boxes would have to be treated on a monthly or bimonthly to remain ant free.