Common Bacterial Blight

Water-soaked lesions on dry bean podsWater-soaked lesions on dry bean pods
Diamondback Moth Larvae Feeding on Cabbage Necrotic lesions with yellow halos on cowpea foliage
Leaf spot with dead center tissue.Lesion typical of bacterial blight
Legume crops showing symptoms of common bacterial blight.Legume crops showing symptoms of common bacterial blight.

HOSTS

  • Legumes

DESCRIPTION

Common bacterial blight is caused by Xanthomonas campestris pv. phaseoli 

BIOLOGY

Common bacterial blight can be introduced to fields and gardens through infected seeds, plant debris, or alternative hosts. The disease can overwinter in contaminated plant debris. In warm, wet conditions, X. campestris can easily be spread mechanically on tools, insects, and water.  

Xanthomonas campestris can survive on outer plant surfaces as an epiphyte, without causing any disease symptoms. This stage can result in a large population of X. campestris, which can further the disease cycle in favorable conditions.  

The bacteria can invade the host plant through the stomata or wounds. If the bacteria reaches the plant’s xylem, the water-conducting tissue, the veins will be clogged with dead cells and bacteria.  

SYMPTOMS

  • Irregularly shaped foliar lesions with brown or tan centers and yellow halos 
  • Water-soaked spots on the underside of leaves 
  • Inner tissue of lesions can become necrotic and fall out 
  • Pods have water-soaked lesions 
  • Chlorotic and wilted foliage  
  • Cream-colored bacterial ooze is exuded from lesions 

GENERAL MANAGEMENT

  • Use certified disease-free seeds 
  • Rotate with nonhost crops  
  • Avoid working with crops when plants are wet 
  • Avoid watering practices, such as overhead irrigation, that result in wet soil and plants for prolonged periods 
  • Remove weeds and volunteer crops that can act as alternative hosts 
  • Remove infected crops and crop debris 

 

 

 

 

 





 

 

Precautionary Statement: Utah State University and its employees are not responsible for the use, misuse, or damage caused by application or misapplication of products or information mentioned in this document. All pesticides are labeled with ingredients, instructions, and risks, and not all are registered for edible crops. “Restricted use” pesticides may only be applied by a licensed applicator. The pesticide applicator is legally responsible for proper use. USU makes no endorsement of the products listed in this publication.