TABLE 1.

Major genera of pathogenic oomycetes

GenusHost(s)Description
Albugo PlantsObligate pathogens of plants
Aphanomyces Animals and plantsMostly pathogens of aquatic animals, but includes pathogens of plants
Bremia PlantsObligate pathogens of plants
Lagenidium AnimalsPathogenic species in this genus infect aquatic animals
Peronospora PlantsObligate pathogens of plants
Phytophthora PlantsMost extensively studied genus, with more than 60 species that cause some of the most severe diseases of dicot plants
Plasmopara PlantsObligate pathogens of plants
Pythium Plants, animals, and microbesMostly plant pathogens, but includes mycoparasites and at least one species that infects humans
Saprolegnia AnimalsPathogenic species in this genus infect aquatic animals, mainly fish