Pierce’s Disease in the North Coast First two sentences: Pierce's Disease (PD) is caused by the bacterium Xyella fastidiosa. The bacterium lives in the water-conducting system of plants (the xylem) and is spread from plant to plant by xylem-feeding insects. Varela_Pierce'sDisease_1997.pdf File Size0.4 MiB DateJune 5, 2013 Downloads1475 AuthorLucia Varela