P.drechsleri was originally isolated from rotting potato tubers. It is primarily a root pathogen.; It is classified in Group VI. Sporangia vary in shape from broadly obpyriform to elongated obpyriform, ovoid to elongate. They are non papillate and persistent on the stalk. P.drechsleri is usually heterothallic. Antheridia are amphigynous, oogonia have tapered bases. Optimal growth temperature is 30 degree Celsius.