Diseases of tomato (
Bacterial canker
Bacterial canker of tomato is caused by the bacterium Clavibacter michiganensis subsp. michiganensis. Leaves of infected plants turn downward and plants wilt. Light colored streaks are common on midribs, petioles and stems. Vascular discoloration is usually visible in stems, and yellow bacterial ooze can be squeezed out of the cut ends of stems of infected plants. Fruit may be stunted and malformed.
The bacterium is seed transmitted, and also can survive in plant debris, weeds,
volunteer tomato plants and soil for several years. It spreads by splashing
water, tools and on contaminated transplants. Contaminated transplants
are the most common source of C. michiganensis in Arizona greenhouses.
Once introduced, new infections take place through wounds such as pruning
cuts, through stomatal openings or even roots. Sanitation is essential
for control. Clean seed, transplants and pasteurized planting mix, as
well as thoroughly disinfecting planting equipment, reduce the chance
of disease.
February 24, 2003