Sensitive varieties such as Barbera, Pinot noir, Fiesta, Chardonnay, and Red Globe develop severe symptoms on several canes by fall if a single cane is infected in April or May. Ruby Cabernet, Reisling, and Cabernet sauvignon inoculated at the same time develop only a few discolored or "scorched" leaves near the point of infection on a single cane. For vines infected by traditional vectors (NOT glassy-winged sharpshooter), most of the vines in less susceptible varieties with these limited symptoms will recover during the next winter. Note in the two photos below the tremendous difference in the types and extent of PD symptoms between the Ruby Cabernet vine (a few discolored leaves) and the Barbera vine (practically the entire vine with symptoms and most leaves gone). The next spring the Barbera vine died, but the Ruby Cabernet vine recovered and was without any symptom of PD the following summer.

(All Photos on this page by A. Purcell)

October symptoms of Ruby Cabernet inoculated the previous April. Fresno County, 1978.

October symptoms of Barbera inoculated the previous April. Fresno Country, 1978.

The old trunk of a grapevine killed by PD is surrounded by growth of the St. George rootstock that suckered up from the base of the dying vine. St. George (Vitis rupestris) is tolerant to Xylella fastidiosa. St. George vines do not have PD symptoms even though the bacteria can occur in high populations in this rootstock variety.

PD symptoms in Flora. Flame Seedless has similar symptoms as Flora, but doesn't develop as fast.

PD symptoms in Red Globe.
PD symptoms in in these 3 or 4 year old Red Globe vines became very severe within a single year. The vines probably were infected in late summer or fall 2000 (or possibly the winter of 2001) and had severe PD symptoms (notice the dried fruit) in August 2001 (Kern County).

Click here for more varieties...

Back to Fall and Summer Symptoms page...

Back to Control Guidelines page...

Back to Main Page...