Insect Growth Regulators: Evaluation Procedures and Activity Against Mosquitoes1

Abstract

In the laboratory, 10 insect growth regulators (IGR) were evaluated against 4th-instars and 4 IGR’s were evaluated against 1st-instal’s and pupae of Culex pipiens quinquefasciatus Say. The latter 4 IGR’s also were evaluated against 4th-instars of Anopheles albimanus Wiedemann. One IGR, TH-6040 [1-(4-chlorophenyl)-3(2,6-difluoro-benzoyl)-urea], showed outstanding activity against all stages of the 2 species. The 4 most active and readily available IGR’s were evaluated against asynchronous populations of Culex tarsalis Coquillett in the field. RO-20-3600 (6,7-epoxy-3-methyl-7-ethyl-1-[3,4-(methylenedioxy)-phenoxy] cis/trans-octene) suppressed emergence of adults for ca. 3–5 days at the rates of 0.25 and 0.5 lb AI/acre. HE-24108 [3-Butyn-2-yl N-(p-chlorophenyl)carbamate] inhibited adult emergence only at the high rate of 0.5 lb/acre, 1 day posttreatment. R-20458 [1-(4′-ethylphenoxy)-6,7-epoxy-3,7-dimethyl-2-octene] yielded complete inhibition of adult emergence from isolates 1 day posttreatment but not 5 days. TH-6040 was the most effective compound evaluated, producing high to complete inhibition of adult emergence 5–15 days posttreatment. An EC and a WP formulation of this compound were equally effective.