ARS | Publication request: FACTORS INFLUENCING GROWTH AND SPORULATION OF PHYTOPHTHORA RAMORUM, CAUSAL AGENT OF `SUDDEN OAK DEATH'

Submitted to: American Phytopathological Society Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: March 15, 2003
Publication Date: June 1, 2003
Citation: BROWNING, M., ENGLANDER, L., TOOLEY, P.W. FACTORS INFLUENCING GROWTH AND SPORULATION OF PHYTOPHTHORA RAMORUM, CAUSAL AGENT OF `SUDDEN OAK DEATH.' Phytopathology. 93:S12. 2003.

Technical Abstract: Phytophthora ramorum has emerged as a new, lethal pathogen on oaks in the U.S. Further, numerous cultivated and wild plants support growth of this pathogen. Little is known about the environmental parameters which influence fungal biology. We investigated the influence of incubation temperatures and illumination regimes on growth and spore production, using thermal gradient plates, at two research facilities. Cultures were incubated on clarified V-8 agar with sterol, at temperatures ranging from 4 - 30C, under 12-hr diurnal light (cool white and near-UV) or darkness. Colony diameters were measured periodically, and number of chlamydospores were counted after 14 days. Sporangia production was assessed on mycelial plugs transferred to autoclaved soil extract and subjected to various temperatures and light regimes. Results with American isolates of P. ramorum, from Lithocarpus densiflorus, Quercus agrifolia, and Rhododendron sp. were compared with those obtained using the type culture isolate (Germany).