As any professional grower or gardener will tell you, Pythium root rot is a nasty pest that, if left untreated, can cause failure of an entire crop in very short order.  Formerly classified as a fungus, scientists have learned much more about the varying “strains” of Pythium and have changed its classification to a pathogen.   Regardless of the type of pathogen involved, the mechanism of action for the Pythium genus remains the same.  Oftentimes Pythium root rot is referred to as “damping off.”