author(s)
Shumaila Mushtaq, Muhammad Uzair Mukhtar, Ali Arslan, Arqam Bakhtyar Zaki, Muhammad Hammad, Adil Bhatti

abstract
Deltamethrin plays an effective role in suppressing the population of malaria and dengue vectors up to less danger level and it is also been used in indoor residual spraying. The residual activity of deltamethrin (K-othrine WP 5%) @ 25 mg/m2 was studied under laboratory conditions on different surfaces. Three sorbent surfaces i.e. cement, mud and plaster were prepared in pans. Wood and filter paper were cut in a situation that cone for carrying out bioassay test could be fitted on them easily. Four blocks were prepared of each surface, from which one block was not treated with insecticide to serve as control. The surfaces were attached to the wall and Deltamethrin WP 5% was sprayed at the dosage of 25mg/m2 using standard Hudson pump at discharge rate 755-780ml/min. The bioassay test was carried out for evaluation of residual effect of Deltamethrin using WHO standard cones. Result of bioassay test on An.stephensi showed that filter paper surface have best residual capacity of Deltamethrin by presenting 67.65% mortality, followed by plaster, wood, cement and mud with % mortality (64.46%, 63.69%, 58.41% and 28.28%) respectively after 5 months of IRS application. Bioassay test on Ae.aegypti showed that filter paper surface have best residual activity of Deltamethrin by presenting 68.76% mortality, followed by plaster, wood, cement and mud with % mortality (64.62%, 59.15%, 57.26% and 40.22%) respectively after 5 months of IRS application. Whole study depicted that residual effect of Deltamethrin on different surfaces is variable. Furthermore, the study highlights proper knowledge of IRS and its management according to building material that may lead to best strategy, which might reduce vector population up to the desired level.