(Photo by Helene and Bill Feil)
Cabernet Sauvignon 18 months after infection. Yolo County, 1998
PD generally is worse in regions with mild winter climates.
Epidemics seem to worsen after mild (warm) winters.
PD symptoms appear sooner in the growing season and become more severe sooner in regions like the Central valley that have a longer and warmer growing season than regions like coastal valleys that have cooler climates.
(Photo by Helene and Bill Feil)
Cabernet Sauvignon 18 months after infection. Yolo County, 1998
This old Cabernet Sauvignon vine in the Sacramento Valley was almost dead in the fall 18 months after an April infection at a single point with blue-green sharpshooter.
Old vines of the same variety in Napa Valley that were inoculated the same week lived for another year.
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