Efficacy of Permethrin as a Larvicide and Adulticide Against Ricefield Mosquitoes in Arkansas1

Abstract

The synthetic pyrethroid, permethrin, provided excellent control of 3rd and 4th instars of Culex pipiens quinquefasciatus Say, psorophora columbiae (Dyar and Knab), and Aedes vexans (Meigen) in the laboratory. The effective 24 h concentration in laboratory larvicide studies against C. P. quinquefasciatus, P. columbiae , and A. vexans was 1.25−1, 2.50−2, and 2.50−2 ppm, respectively. In 6.1×6.1-m rice plot larvicide tests against P. collumbiae larvae, the rate of 11.22 g AI/ha was effective when larvae were introduced in 1 h posttreatment. At 24 and 48 h posttreatment, 168.12 g AI/ha was required to give 90% control. After 72 h, the rate required for 80% control was 280.2–560.4 g AI/ha with only the 560.4 g AI/ha rate being effective after 96 h. When permethrin was evaluated against adult Anopheles quadrimaculatus Say, P. columbiae , and C. P. quinquefasciatus exposed in a wind tunnel, 24-h LC50’s were 32.0-, 2.0-, and 9.6-fold more effective than malathion for each species, respectively. ULV applications by truck-mounted aerosol generators at the rate of 2.91 g AI/ha produced over 90% mortality in caged C. P. quinquefasciatus placed at various down wind positions.