The first reports of ‘bacteria-like bodies’ associated with a plant caused by Xylella fastidiosa referred to alfalfa dwarf in the 1920s (Weimer 1937). The disease has never been a problem north of Fresno County. The main vectors are assumed to be grass-feeding sharpshooter leafhoppers, the green sharpshooter and the red-headed sharpshooter. The impact of the disease is that alfalfa stands with dwarf disease have to be replanted much sooner than normal. Symptoms of alfalfa dwarf differ sharply from Pierce’s disease and other leaf scorch diseases caused by X. fastidiosa. Alfalfa plants decline slowly after infection. They are slower to grow after cutting and have smaller,darker colored leaves and stems compared to healthy plants. A diagonal slice of the taproot reveals that the woody tissue of the root has a yellowish color, with streaks of brown dead wood.
A scientific and community resource on plant diseases caused by the bacterium Xylella fastidiosa