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What Is It? | Facts in Depth | For the Professional Diagnostician
Tomato Diseases | Bacterial Leaf Spot Fact Sheets

Bacterial Leaf Spot of Tomato




  • Greasy water-soaked spots on leaflets
  • Older spots are dry and brown and often surrounded by yellow halos
  • Spots increase in size to form large irregular dead spots
  • Spots are most often observed on the entire surface of fully expanded leaves by may also appear on the steam and the flower bugs
  • Severe infections may cause the plant to lose its leaves.

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  • Small, greasy water-soaked spots on the green fruit that become slightly raised and enlarged (1/4 inch)
  • Older spots are irregular in shape, light brown to black, slightly sunken and have a scabby surface texture

 Favorable Environmental Conditions

  • Warm temperatures (75-90 °F)
  • High moisture
  • High relative humidity

Often Confused With


Scouting Notes

  • The pathogen can be active from the time of plant emergence through to harvest.
  • Foliar symptoms of bacterial spot and speck are identical.
  • Fruit symptoms are diagnostic, based on spot size, appearance and texture.
  • Early spots can appear whitish, resembling bacterial canker “bird’s eye” spots
  • Greenhouse seedlings and plants in the field should be monitored weekly for early symptoms and suspect plants should be sampled and submitted for plant disease diagnosis.