Laboratory Study Of Persistence And Residual Activity Of Pyrethroid Against Anopheles Stephensi And Aedes Aegypti (Diptera: Culicidae) In Pakistan

Abstract:
Present study was carried out to test the residual activity of deltamethrin EC 1.5%, K-Othrine EC 1.5% and deltamethrin WP 5% under laboratory conditions on five different surfaces i.e. cement (concrete), mud, plaster, wood and filter paper. Four blocks were prepared for each surface, from which one block was not treated with insecticide to serve as control. The surfaces were attached to the wall and deltamethrin EC 1.5% , K-Othrine EC 1.5% and deltamethrin WP 5% were sprayed using standard Hudson pump. The bioassay test was carried out for evaluation of residual effect of insecticides using WHO standard cones. Result of bioassay test on aedes aegypti showed that deltamethrin 1.5% EC had best residual capacity on filter paper indicating 60.90% mortality and for Anopheles stephensi plaster surface had best residual effect showing 77.75% mortality after 2 months of Indoor Residual Spraying (IRS) application. For K-Othrine, filter paper had best residual capacity for both mosquito species. Deltamethrin WP 5% depicted different residual effects on different surfaces showing 58.33% mortality on filter paper against An. stephensi and Ae.aegypti showed 65.72% mortality on mud after 2 months of IRS application. The study also 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.