Type: Foliicolous Fungi; Description: Colonies on carrot agar with a rosette pattern, felted, with scant fluffy aerial mycelium. Chlamydospores none. Sporangia produced only on plant material floated on pond water and not in artificial culture, terminal, occasionally proliferating internally, ovoid, 25–50 × 20–38 μm, non-papillate. Oogonia globose, 16–35 μm in diameter, smooth, hyaline, base tapered. Antheridia amphigynous, long and tapering towards the base, often with two cells. Oospores aplerotic, 13–30 μm in diameter.

Distribution: Bay of Plenty.; 1st Record: Dick et al. (2001).

Significance: Most species of Phytophthora recorded as being associated with trees and shrubs in New Zealand are soil-borne and infect roots and the lower stem. These two species are unusual in that they are found in dying leaves in the crowns of eucalypt trees at a height of up to 20 m. Locally severe crown dieback associated with foliage, shoot, and twig infection by these two Phytophthora species has been recorded in E. botryoides and E. saligna in the Bay of Plenty and in E. delegatensis in Southland. The occurrence is episodic and infection appears to take place during the winter months. Infected leaves are readily abscised, defoliation and twig infection leading to dieback of the crown. The fungi can be isolated from soil beneath infected trees but as the sporangia of neither species are deciduous, it is not known how the fungi reach foliage high in the tree crown. Pathogenicity of Phytophthora ‘captiosa’ to E. botryoides, E. regnans, and E. saligna has been established in laboratory tests.; Host(s): Eucalyptus botryoides, E. saligna.