Integrated Pest Management Reviews (2001) 6, 243-246

Brice A. McPherson, David L. Wood, Andrew J. Storer, N. Maggi Kelly and Richard B. Standiford (2001)
Sudden oak death, a new forest disease in California
Integrated Pest Management Reviews 6 (3-4), 243-246
Abstract: A forest disease caused by a newly described pathogen, Phytophthora ramorum, is presently affecting a number of woody plant species in central and northern coastal California and southern Oregon, U.S.A. Among the most severely affected tree species are coast live oak, Quercus agrifolia, and tanoak, Lithocarpus densiflorus. In March 2000, we established plots in Marin County, CA, to assess symptom progression and the association of other organisms with diseased trees. Symptomatic trees exhibit 'bleeding' of viscous sap from apparently intact bark, typically within approximately 2 m of the soil. At least three species of bark and ambrosia beetles colonize bleeding oaks. These beetles colonized every bleeding tree that died during the first year of the study (N = 23) while the foliage was still green. By March 2001, numbers of symptomatic and dead trees increased for both coast live oak and tanoak. Symptomatic coast live oaks totaled 26% in March 2000 and 27% in March 2001. During the same period, mortality increased from 6% to 10%. For tanoaks, 41% were symptomatic in 2000, rising to 49% in 2001. Mortality was 11% in 2000 and 13% in 2001. The values for coast live oak are broadly consistent with independently acquired infection and mortality estimates derived from an unbiased transect method.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Database assignments for author(s): Andrew J. Storer

Research topic(s) for pests/diseases/weeds:
population dynamics/ epidemiology
environment - cropping system/rotation

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Phytophthora ramorum	Oak (Quercus)	U.S.A. (SW)
	Phytophthora ramorum	Tanoak (Notholithocarpus)	U.S.A. (SW)