This
bacterial disease is particularly damaging to vinifera grapes and interspecific
hybrids. The major symptom is fleshy galls on the lower trunk near the soil.
Galls may also form up to 3 feet high on trunks and canes and on below-ground
plant parts.
Initially,
galls are cream-colored and fleshy, but later they turn brown
and woody. Affected vines appear weak and portions of the vines
above the galls may die. They may also be more prone to freeze
injury. Young vines may be girdled by galls in one season. The
crown gall bacterium lives in the soil and enters the plants
through wounds caused by freeze injury, mechanical damage, grafting
or insect damage. Crown gall may be confused with natural callus
growth at graft unions. |
