Assessing the bioefficacy of a commercial temephos formulation (Temebate®) for controlling Aedes albopictus larvae in different land use localities in Malaysia

Temephos is the World Health Organization (WHO) recommended larvicide and is still being utilized worldwide to control larvae of dengue vectors; Aedes aegypti and Aedes albopictus. The efficacy of a commercial temephos product; Temebate® to exterminate the local populations of Ae. albopictus larvae originated from different land use particularly dengue-risk and dengue-free housing localities as well as agrarian localities including oil palm plantations, rubber estates and paddy fields was assessed to verify its bioefficacy in these localities. Field populations of Ae. albopictus larvae were attained via a larval survey at each study locality. Each Ae. albopictus larval population was subjected to a 24-h larval bioassay using Temebate® at operational dosage of 1 mg/L. Almost all Ae. albopictus larval populations demonstrated mortalities between 7.00% and 100.00% by the end of the first 4 h of Temebate® exposure with the resistance ratios between 0.94 and 8.33. After 24 h of Temebate® exposure, all sixteen Ae. albopictus larval populations exhibited increased mortalities with ten of them showing 100% mortalities. These results confirmed the relevance of Temebate® to be continuously used by the residents of these localities as their control efforts against dengue vectors. Nevertheless, Temebate® application by consumers in dengue-risk localities need to be carefully monitored to prevent further development of temephos resistance among Ae. albopictus populations and substantiated with other vector control approaches.