Comparison of dilute and neat formulations of Anvil by ultra-low volume ground application against Anopheles quadrimaculatus in Arkansas

Neat (undiluted) and diluted ground-applied ultra-low volume (ULV) cold aerosol formulations of sumithrin (Anvil) were evaluated against Anopheles quadrimaculatus adults. Both formulations were applied at 1.938 g/AI/ha (0.00173 lb/AI/acre). Caged sentinel mosquitoes were placed on 1.5-m stakes 30.4, 60.9, and 91.0 m downwind and perpendicular to the line of spray. Mortality was observed at 1, 12, and 24 h posttreatment. Except for 1-h readings at 30.4 and 91.0 m the neat formulation was significantly more effective than the dilute. Droplet size and density averaged 13.6 microm and 422/cm2 for dilute formulation and 14.3 microm and 251/cm2 for the neat. There was no apparent relationship between droplet size and density when compared with mosquito mortality.