Microwaving an insecticide restores its mosquito-killing power
Heating an insecticide can give it new life. Microwaving the insecticide deltamethrin rearranges its crystal structure but doesn’t change its chemical composition. The rearrangement renews deltamethrin’s ability to kill mosquitoes that have become resistant to the insecticide, researchers report April 21 in Malaria Journal. The researchers didn’t set out to revive insecticides, says Bart Kahr, a crystallographer at New York University. He and colleagues had been working on crystal growth experiments. “And it turns out that a very good crystal for the experiment that we wanted to do was DDT, the very old, notorious insecticide from the last century.” The researchers realized that DDT has two crystal forms, one of which works better than the other. They then started experimenting with deltamethrin, an insecticide that is commonly used against mosquitoes that can carry malaria. The chemical is often incorporated into bed nets or sprayed on walls or other surfaces in homes. Mosquitoes absorb...