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Photo: Electron Microscopy Laboratory,
U.C. Berkeley |
Xylella fastidiosa
(Wells et al. 1987) is a gram-negative, fastidious, xylem-inhabiting bacterium.
It causes serious diseases in grapevines (Pierce’s disease), almonds
(Almond leaf scorch), alfalfas (Alfalfa dwarf), and oleanders (Oleander
leaf scorch) in California and numerous other diseases in North and South
America. An epidemic of oleander leaf scorch was first noticed in 1994 in
southern California. It was found that the glassy-winged sharpshooter, Homalodisca
coagulata Say, as well as several other sharpshooters, could transmit
X. fastidiosa from oleander to oleander. Description of almond, oleander,
and other leaf scorch diseases caused by different strains of X. fastidiosa
can be found at the following website: http://www.CNR.Berkeley.EDU/xylella/
Causative agent of almond leaf scorch. |
Characteristic symptoms:
leaf scorch followed by decreased productivity and eventually death (within
3 to 8 years after the onset of leaf symptoms).
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