Nosema is a genus of microsporidian parasites, including
*Nosema equestris parasitising the chrysomelid beetles Gastrophysa viridula and Leptinotarsa decemlineata''
Nosema locustae, which parasitises locusts, and Nosema grylli, which parasitises crickets, have been transferred to Paranosema, or in the former case Antonospora. Nosema algerae, which parasitises anopheline mosquitoes has been transferred to Brachiola. Nosema kingii, which parasitises fruit flies, and Nosema acridophagus, which parasitises grasshoppers, have been transferred to Tubilinosema.
Studies of DNA sequences imply that the boundaries between the genera Nosema and Vairimorpha are incorrectly drawn.