Abstract

Objective: To evaluate the efficacy of a synergized pyrethroid formulation containing 0.8% w/ w s-bioallethrin, 18.7% w/w permethrin and 16.8% w/w piperonyl butoxide. Methods: Cold fogging was carried out against Aedes aegypti (Ae. aegypti) and Culex quinquefasciatus using a synergized pyrethroid formulation containing 0.8% w/w s-bioallethrin, 18.7% w/w permethrin and 16.8% w/w piperonyl butoxide. Three cages each containing 15 mosquitoes and paper cups each containing 25 larvae in 250 mL of water were deployed at each test pole between 10 and 40 feet. The formulation was diluted as 1:33, 1:50 and 1:100, respectively, and applied using a mist blower. Results: Using the dilution ratio of 1:33 and 1:50, 100% adult knock-down was recorded after an hour of post spraying at all checkpoints for both species. The percentage of adult mortalities for both species at 24 h post spraying ranged from 80% to 100%. Moreover, complete mortalities of Ae. aegypti larvae were demonstrated for both dilution ratio of 1:33 and 1:50 at all checkpoints. Meanwhile, complete mortalities of Culex quinquefasciatus larvae were recorded only at 10 and 20 feet with dilution ratio of 1:33. Conclusions: These results showed that cold fogging using synergized pyrethroid formulation tested was more effective against Ae. aegypti between 10 and 30 feet with dilution ratio of 1:33.

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