a genus of fungi of the order Entomophthorales. The fungi are parasites of insects. The spores, or conidia, sprout upon landing on the insect; they form a mycelium, which penetrates the insect’s body and proliferates. Toxins secreted by the fungus destroy all the insect’s internal organs.

There are about 20 species. The most widespread are E. aulicae and E. grylli. The former causes mass destruction of the pine beauty moth, the gold-tail moth, and the lackey moth—all dangerous pests of timber crops. E. grylli parasitizes grasshoppers (Acrididae). Some mycologists include the Empusa in the genus Entomophthora.