Bacterial Blight

Bacterial Blight on soybean leafIn the vegetable garden, bacterial blight is most often a problem on snap beans and lima beans. (Note that other crops also suffer from bacterial diseases that may be called bacterial blight.) Symptoms of infection are large, water-soaked, pale green spots on leaves that later turn brown. These spots may also appear on pods and can produce a yellowish ooze in wet weather. Leaves infected with halo bacterial blight develop many small dead spots with yellow halos around them; spots on pods produce a cream-colored ooze.

The bacterium overwinters on plant debris and in the soil. High humidity and wet weather promote the spread of the disease.

Prevention and Control

  • Use a three-year crop rotation for beans.
  • Space rows and seeds more widely than usual to allow good air circulation among plants.
  • Don't work in the garden when plants are wet. Splashing water spreads bacteria among plants. Use drip irrigation or soaker hoses rather than overhead watering.
  • Uproot infected plants and destroy them.
  • Do not save and plant seeds from infected plants.

Last updated: 03/18/2024