Postdoctoral fellow Jean M. Deguenon (left) and his advisor R. Michael Roe (right, holding a mosquito chamber) and colleagues studied the effects of a commercial preparation of perlite called Imergard. They found that Imergard was an effective insecticide against the African malaria mosquito Anopheles gambiae, making it a promising option for control of malaria and other mosquito-borne diseases. (Photo courtesy of Jean M. Deguenon, Ph.D.)