here are insect diseases caused by pathogens (bacteria, fungi, etc.), and Insect Pathologists are the Entomologists who study these pathogens. There are many pathogens that attack insects, so I’ll just list a few.

Nosema apisZonder and Nosema ceranae are microsporidian parasite of the European honey bee, Apis melliferaLinnaeus. They cause nosemosis, also called nosema, which is the most common and widespread of adult honey bee diseases.

Milky spore disease is a caused by the bacterium Paenibacillus papillae (Dutky 1940) Pettersson et al. The bacterium is applied to turfgrass as a dust. It is effective only in controlling grubs of the Japanese beetle, Popillia japonica Newman.

The citrus whitefly, Dialeurodes citri (Ashmead) and cloudy winged whitefly, Singhiella citrifolii (Morgan) are attacked by fungal species of Aschersonia andAegerita. Both whitefly species are attacked by Aschersonia aleyrodisWebber and Aegerita webberi Fawcett. The cloudywinged whitefly is also attacked by Aschersonia goldianaSaccardo & Ellis.

The velvetbean caterpillar, Anticarsia gemmatalis (Hübner) is attacked by several pathogens, mainly fungi. The most important pathogens are the fungi Nomurea rileyi (Farlow) Samson and Entomophthora sp.