Pythiaceae

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