ARS | Publication request: Infectivity of Phytophthora Ramorum on Selected Ericaceous Host Species

Submitted to: American Phytopathological Society Abstracts
Publication Type: Abstract
Publication Acceptance Date: March 15, 2002
Publication Date: June 1, 2002
Citation: TOOLEY, P.W., ENGLANDER, L. INFECTIVITY OF PHYTOPHTHORA RAMORUM ON SELECTED ERICACEOUS HOST SPECIES. Phytopathology. 92:S81. 2002.

Technical Abstract: Phytophthora ramorum, suspected causal agent of sudden oak death in California, was evaluated for its ability to infect ornamental plant species in the family Ericaceae. P. ramorum was reported by European workers to attack plants in the genera Rhododendron and Viburnum, and has been isolated from rhododendrons and other varied plant species in California. Leaves on whole plants were inoculated by cutting off the tips (2-3 mm) and dipping them in P. ramorum mycelial suspension, followed by incubation for 7 days in a dew chamber at 20 C in darkness. Mean lesion areas, as percentage of leaf areas were 10.2% for Arctostaphylos uva-ursi, 5.9% for Rhododendron maximum, 15.9% for "Girard's Rose" azalea, 4.4% for florist azalea "Inga", 31.8% for Kalmia latifolia "Madeline", 27.8% for Pieris floribunda, 32.6% for Zenobia pulverulenta, and 17.4% for "Cunningham's White" rhododendron. Isolate 0-217 from rhododendron in California appeared less virulent than P. ramorum type culture 9/95. Additional research is needed to determine the role these potential hosts may play in the epidemiology of sudden oak death.