Soybean Diseases in Ohio

Septoria brown spot

• Symptoms
  • angular red to brown spots on upper and lower leaf surfaces
  • leaves turn yellow and fall to the ground
  • tan lesions becoming dark brown on trifoliate leaves
  • infected leaves turn rusty brown and drop
  • defoliation from bottom to top
  • irregular brown lesions on pods, stems and petioles
• Environment
  • high moisture and moderate temperatures 60 to 85°F
• Survival
  • fungus overwinters in soybean straw
  • spores infect seedlings
  • spores from infected seedlings provide inoculum for late infections of trifoliate leaves, stems and pods
• Management
  • crop rotation
  • in heavily infected fields plow under soybean straw
• Scouting