Pierce's disease of grapevine
depends on the plant species: in peach, bacteria are found in high numbers in the roots, whereas in plum, high numbers are found in leaves and fruits. The bacteria [...] die. This happens faster in younger vines than in older ones and faster in susceptible cultivars (within 2-3 years) than in more tolerant cultivars, which [...] bacteria live in xylem vessels in roots, stems and leaves and multiply. The plant may react by producing gum and tylose, a glue-like substance, in the vessels