Aphanomyces

The Oomycete genus Aphanomyces comprises devastating plant and animal pathogens. Oomycetes form a phylogenetically distinct group of eukaryotic microorganisms which includes plant and animal pathogens, which cause widespread damages of high economical and ecological impacts. Pathogenic oomycete species are found mainly in three orders, the Pythiales, the Peronosporales and the Saprolegniales. From recent studies on the phylogenic relationships within oomycetes, it has been suggested that the ability to infect plants appeared at least twice in the oomycete lineage, first in an ancient lineage which evolved into the Pythiales (including Phytophthora and Pythium) and Peronosporales, and secondly in the Saprolegniales lineage which includes destructive animal pathogens such as the fish pathogens Saprolegnia parasitica and Aphanomyces piscida, and plant pathogens such as A. euteiches and A . cochlioides.

A. euteiches causes seedling blight and root rot of legumes, such as alfalfa and pea. The legume root rot disease caused by A. euteiches is one major yield reducing factor in legume production throughout the world.