Pesticide

mosquitoes would be a more sustainable way of controlling malaria, according to entomologists who add that the approach may lead to evolution-proof insecticides that never become obsolete. Each year malaria-- spread through mosquito bites-- kills about a million people, but many of the chemicals used to kill the insects become ineffective. Repeated exposure to an insecticide breeds a new generation of mosquitoes that are resistant to that particular insecticide. "Insecticides sprayed on house walls or bed nets are some of the most successful ways of controlling malaria, " said Andrew Read, professor of biology and entomology, Penn State. "But they work by killing the insects or denying them the human blood they turn into eggs. This imposes an enormous selection in favor of insecticide-resistant mosquitoes." Read and his colleagues Matthew Thomas, professor of entomology, Penn State, and Penelope Lynch, doctoral student, Open University, UK, argue that insecticides--chemical or biological-- that kill only older mosquitoes are a more sustainable way to fight the deadly disease. "If we killed only older mosquitoes we could control malaria and solve the problem of resistant mosquitoes, " said Read. "This could be done by changing the way we use existing insecticides, even by simply diluting them, " he added. Aging mosquitoes are easier to kill with insecticides like DDT but new generation pesticides could do it too. Read and his colleagues are working with a biopesticide that kills older mosquitoes. "It is one of the great ironies of malaria, " explained Read, whose team's findings appear today (April 7) in PLoS Biology. "Most mosquitoes do not live long enough to transmit the Ads by Google Advertise here Repeated exposure to an insecticide breeds a new generation of mosquitoes that are resistant to that particular insecticide. (Credit: Image courtesy o