Characterization of targeted swarm spraying with refillable aerosol cans compared to broadcast space-spray applications via a backpack sprayer

摘要

Malaria control strategies in Africa have focused on Indoor Residual Spraying IRS and Long-lasting Insecticide-treated Nets (LLINs). While these strategies have made a significant impact on the prevalence of Malaria they are insufficient for eradication due to an increase in outdoor biting. This means an effective and sustainable method is required to control outdoor biting mosquitoes. Recognizing that male Anopheline mosquitoes gather in mating swarms at dusk creating a concentration in the population, it was hypothesized that targeted spraying of these swarms will knock back the mosquito population with less chemical than conventional space spray application techniques. Field trials in 2016 showed that swarm spraying was a point source precision application that would use less chemical than a conventional space spray application. The selected pesticide formulation, Actellic 50EC (pirimiphos methyl), was assessed for longevity of activity after dilution, showing a decline at 5 days after mixing. Because Actellic does not have a rapid knockdown, it takes - 1 h till mortality, the question was can a mosquito still mate after being sprayed. No insemination was observed with lethal or sub-lethal doses whereas control cages showed 12% of the females were inseminated. In 2017 the targeted swarm spraying technique has been put into practice in four villages, four further villages received a conventional space spray with a backpack aerosol generator and two control villages received no outdoor biting spray intervention. This work is in continuation but is would appear that population decline is significant and less chemical was used with the handheld sprayers compared to the conventional application. These positive results provide confidence that thistechnique could be a sustainable, community based precision pesticide application for mosquito control, and another step toward Malaria eradication.