ABSTRACT
Phytophthora humicola, a new species which forms large hyphal swellings with radiating hyphae, was isolated from soil of a citrus orchard in Taiwan. The fungus produces nonpapillate, nondeciduous sporangia and relatively large oogonia with predominantly paragynous antheridia, both with long stalks. Phytophthora humicola and P. insolita isolated from soil of a nearby citrus orchard were pathogenic to fruits of apple and cucumber but not sweet orange and eggplant.