Pythiaceae

Pythiaceae is a family of oomycetes. The family includes serious plant and animal pathogens in the genus Pythium. The family was circumscribed by German mycologist Joseph Schröter in 1893.

Lifecycle

 * Live on land (terrestrial), and in water (aquatic), or a combination of the two (amphibious).
 * Most are deadly parasites, causing root rot and damping off on plants and pythiosis on animals.
 * The diploid (2N) life stage predominates, with a short haplophase initiated during sexual reproduction before the fusion of the gametes. Most species are homothallic.

Reproduction
The sporangia may germinate via a germ tube or by release of motile zoospores, depending on the species and the environmental conditions.

Economic importance
Some Pythium species cause "damping off" diseases in young plants (seedlings).