Pythiales is an order of water-molds (

oomycete Oomycota forms a distinct phylogenetic lineage of fungus-like eukaryotic microorganisms, called oomycetes (). They are filamentous and heterotrophic, and can reproduce both sexually and asexually. Sexual reproduction of an oospore is the resul ...

s). Some species of this order are the causative agents of several economically important plant diseases, such as

potato blight ''Phytophthora infestans'' is an oomycete or water mold, a fungus-like microorganism that causes the serious potato and tomato disease known as late blight or potato blight. Early blight, caused by ''Alternaria solani'', is also often called "po ...

References

Water mould plant pathogens and diseases Heterokont orders Water moulds {{watermould-stub