Tissue Proliferation

Symptoms

Vascular tissue differentiation associated with tissue proliferation distinguishes it from wound callus and crown gall. Another characteristic is that many small shoots develop from the galled area. Crown gall is solid, looks somewhat uniform, and has malformed vascular tissue, but tissue proliferation has developed vascular connections. Tissue proliferation generally is at the plant's base but can be on shoots. It has not been seen on roots, another distinction from crown gall. The excessive tissue growth may deteriorate after several years of plant growth. Plants appear healthy as a whole, and growth is not seriously affected. However, growers in some Eastern States have observed slow decline, wilting, and eventual death of affected plants. If tissue proliferation circles the stem of small or young plants, the plant may die due to the vascular system's disruption. Plants seem weakened at the proliferation site, so limbs on the stem may dislodge or break off easily. This problem may be confused with witches' broom, which is characterized by several woody shoots arising from the bud near the terminal part of the plant. Gall-like growth is not associated with witches' broom.