Efficacy of Bay Sir 8514, an insect growth regulator, against Psorophora columbiae and Anopheles quadrimaculatus in small plot and field trials.

Four formulations of an insect growth regulator, Bay Sir 8514 (a benzoylurea compound), were tested against 2 species of riceland mosquito larvae, Anopheles quadrimaculatus and Psorophora columbiae. Formulations of 25% WP, 0.5% G and 065 EC (65 g/liter) were tested at dosages of 14, 28, 56, and 84 g ai/ha in small plots. The 14 g ai/ha rate was ineffective for all formulations while the 28, 56 and 84 g ai/ha provided 100% mortality through 48 hr posttreatment. The 84 g ai/ha rate gave complete control through 7 days posttreatment. A 4 F formulation was applied aerially at rates of 24.9 and 49 g ai/ha to a 9.7 ha rice field. The 24.5 g ai/ha rate provided marginal control at 24 hr posttreatment but failed to control larvae at 48 hr. At 49 g ai/ha, the material provided control through the 48 hr posttreatment.