Pathogens are bacteria, viruses, nematodes, and fungi. Insects, like humans and plants, can be infected with pathogens that cause diseases. Insect pathogens generally kill, reduce reproduction, slow the growth, or shorten the life of a pest insect. Unlike chemical insecticides, microbial insecticides usually take longer to kill or weaken the target pest. But under certain conditions, such as high humidity or high pest populations, these pathogens can cause disease outbreaks that decimate an insect population. Pathogens are most effective when pest populations are very high. Pathogens are...