Microsporidia

Microsporidia have been reported to cause substantial deleterious effects on host fitness in host insects.

These effects include malformations in infected pupae, increased larval mortality, developmental delay of immatures, reduced fertility and longevity of adults, and increased susceptibility to stress conditions.

These stress factors cause biological changes in the host insect and may be associated with a decrease in its rate of parasitism.

As microsporidian pathogens generally display efficient transmission mechanisms and moderate virulence, these traits may make them more effective agents in establishing enzootics in host population, as evidenced by the use of a microsporidium to control grasshoppers.