Bacterial Spot on Pepper and tomatoes

Encyclopedia Article

Overview of bacterial spot on pepper and tomatoes

Bacterial spot on pepper is caused by the bacterium Xanthomonas campestris pv. vesicatoria. Warm and humid conditions favor the disease. The disease organism can be spread by rain or during overhead irrigation.

Signs and symptoms of bacterial spot on pepper and tomatoes 

Image of bacterial spot symptoms in Pepper
Bacterial spot symptoms in Pepper

Leaf spots on affected leaves are at first small, yellow-green lesions with a water-soaked border. These spots may coalesce, giving a blighted appearance. Eventually, these spots turn brown and dry up, leaving holes in the leaves. A tattered appearance of the leaves often results. Fruit spots are raised, scabby areas. Fungi may enter these spots and cause secondary fruit rots.

Type of Sample Needed for Diagnosis and Confirmation

The Iowa State University Plant & Insect Diagnostic Clinic can help you to investigate and confirm if you plant has this disease. Please see our website for current forms, fees, and instructions on collecting and packing samples. Contact information for each states diagnostic laboratory for U.S. residents.  If your sample is from outside of Iowa please do not submit it to the Plant & Insect Diagnostic Clinic without contacting us


Bacterial spot is difficult to control once it is present. The following recommendations will aid in control:

  • Use only inspected, healthy transplants.
  • Avoid working around plants when the foliage is wet.
  • Do not plant peppers or tomatoes in the same spot in successive years.
  • Control weeds, especially nightshade and ground cherry. (The bacterium has been shown to survive on these solanaceous weeds.)
  • Applications of a fixed-copper fungicide can slow the spread of the disease but will not eradicate existing infections.
  • Remove infected plant debris or plow under deeply.