Pirimiphos-Methyl 300Cs, The Reinvention Of An Effective Mosquito Adulticide

Abstract:
Control of the Anopheline vectors is the most effective approach to malaria control. Reductions in mortality and morbidity from malaria have been achieved through the use of pyrethroid treated bed nets, pyrethroid resistant mosquitoes threaten the effectiveness of this valuable intervention. Insecticide resistance management (IRM) dictates that the target insect should not be continually exposed to the same class of insecticide to break the selection pressure for a resistance mechanism. Currently this cannot be achieved with the use of World Health Organisation’s Pesticide Evaluation Scheme (WHOPES) approved Long Lasting Insecticide Treated bed Nets (LN). One approach to break the cycle of continual pyrethroid exposure is to employ indoor residual wall spraying (IRS) with a non-pyrethorid insecticide. IRS has been shown to be an effective method of controlling the Anopheline vectors of malaria. Pirimiphos-methyl is a WHOPES approved organophosphate insecticide which has been used as an emulsifiable concentrate formulation for IRS, and has been shown to control pyrethroid resistant mosquitoes. On some wall surfaces season long mosquito control may not be delivered. Supported by the Integrated Vector Control Consortium Syngenta developed a microencapsulated formulation of pirimiphos-methyl which provides control of Anopheles mosquitoes on typical wall surfaces. This paper discusses the biological behaviour of the microencapsulated formulation of the organophosphate insecticide, pirimiphos-methyl, developed specifically for use in mosquito vector control.