Mosquitoes and black flies are a constant threat to health and comfort, yet the modern chemical pesticides used to control them have cre- ated serious ecological problems. Populations of resistant mosquitoes and black flies have evolved, beneficial insects and natural predators have been destroyed, and environmental pollution has increased worldwide. Therefore, scientists have energetically sought new, environmentally safe technologies to combat mosquitoes and black flies and the diseases they carry. Among the most effective alternative means of controlling these pests are the highly spe-...