Xanthomonas vesicatoria

Bacterial leaf spot on peppers and tomatoes is caused by a gram-negative and rod-shaped bacterium in the genus Xanthomonas. It causes symptoms throughout the above-ground portion of the plant including leaf spots, fruit spots and stem cankers. There are four pathovars classified in three different species that can cause this disease, named by alphabetical groups. Nevertheless, the prevention and treatment is very similar: since this bacterium cannot live in soil for more than a few weeks and survives as inoculum on plant debris, removal of dead plant material and chemical applications to living plants are considered effective control mechanisms.