When we use an insecticide, we hope to kill all the pesky pests that encounter it. But a scientist at Pennsylvania State University now says that killing just older mosquitoes would be a better way to wipe out malaria, which kills about a million people a year.
The problem, says Andrew Read, professor of biology and entomology, is that killing mosquitoes that are still of breeding age is more likely to result in development of resistance to the chemicals in the insecticides in future generations, making them obsolete.
Most mosquitoes do not live long enough to transmit malaria, which takes 10 to 14 days to reach their salivary glands and become dangerious to humans. So, if you kill just the older ones that are finished breeding, you don’t give them a chance to evolve to be chemical-resistant.
Read and colleagues are working on new bio-insecticides that are longer-acting, killing mosquitoes with fungi that take 10 or 12 days to act after exposure. In effect, they are hoping to make evolution-proof insecticides.A NEW WAY TO FIGHT MALARIA