Bacterial canker of tomato is an economically important disease found throughout the world. It’s main host is tomato, but it can infect a few other crops. Outbreaks can cause tomato plants significant damage.
Bacterial canker enters the host plant mainly through hydathodes, stomates, and wounded tissue. After entering, the pathogen can become systemic and move through the xylem tissue.
Once bacterial canker is established on plants in the field, it can easily spread from plant-to-plant by water splashing and contaminated tools on workers clothes and hands. The disease favors relatively high temperatures (24-29 degrees Celsius) and a high relative humidity (80% and above).
Bacterial canker symptoms usually manifest on lower foliage first and include: curling and wilting of leaves and branches. Chlorosis, brown necrosis, and the shriveling of leaf tissue are also common and may develop only on one side of the leaf. With time, vascular tissue turns tan in color and eventually red-brown.
Observing fruit symptoms is useful in diagnosing bacterial canker. Small, round white to yellow spots with brown centers may develop on green fruits.
In advanced stages, pith separates from the vascular tissue along the stem, and as a result, hollowing of the stem occurs.