Bacterial canker is characterized by wilting and eventual death of the lower leaves, with the leaves drying up while still attached to the stem. Vascular tissue is discolored, brown, or brownish-yellow, and a characteristic yellow slime can be squeezed from affected stems. The bacterium that causes this disorder may be seed or soil born.
Crop rotations and careful seed source selection are primary considerations. Seed beds in infected areas should be sterilized. Mechanical damage to the transplants (such as topping) spreads the disease.