Bacterial Blight – Pseudomonas syringae pv. glycinea

Background Information
  • Bacterial blight is a common bacterial disease of soybean. It can infect all aerial plant surfaces and is favored by cool, wet conditions.
Disease Agent
  • Pseudomonas syringae pv. glycinea is a bacterium that also infects snap bean and lima bean. The pathogen overwinters in crop residue and can be seed transmitted.
Symptoms
  • Lesions on leaves and pods are easiest to see but can occur on all aerial plant parts.
  • Infections begin as small, water-soaked spots that turn yellow ant then brown as the tissue dies. Spots may merge to form dead patches, and the dead tissue may fall out.
  • Seedlings may be stunted or killed if apical tissue is infected, and brown lesions may cover much of infected pods.
Time of Occurence
  • All seasons
Conditions Favoring Disease
  • Cool, wet weather and rainstorms.
  • Disease progress stops when conditions become hot and dry.
  • The pathogen can be spread by wind and rain in fields, as well as by cultivation when foliage is wet.
Disease Managment
  • Rotate with nonhost crops.
  • Plant resistant varieties.
  • Avoid field cultivation when foliage is wet.
  • Use pathogen-free seed.
  • Plowing to bury soybean residue may be helpful