Bacterial Pustule

  • Symptoms

  • Trigger

  • Biological Control

  • Chemical Control

  • Preventive Measures

Bacterial Pustule

Xanthomonas axonopodis

Bacteria


In a Nutshell

  • Light green spots with raised centers appear on both sides of leaves.
  • Pustules develop in the center of spots.
  • Brown irregular necrotic patches form.
  • Patches can fall off and give the leaf a ragged appearance.

Hosts

Soybean

Symptoms

Minute, light green spots appear on one or both sides of the younger leaves. These spots have raised centers and later develop into small light-colored pustules situated along the leaf veins. At later stages of the disease, these spots fuse and form large brown irregular lesions. These dead areas can be torn away by wind, giving the leaf a ragged appearance. Small raised spots may also develop on pods. The disease can cause premature defoliation and reduced seed size and quantity.

Trigger

The bacteria overwinters in crop residues or on seeds in the soil. It is carried by the wind, water droplets, and insects and enters the plant through natural openings or mechanical injuries. The disease is promoted by warm and wet weather conditions with frequent showers and wet foliage. Optimal temperature for disease development is in the range of 30-33°C. Potash and phosphorous seem to play an important role in the management of this pathogen.

Biological Control

Sorry, we don't know of any alternative treatment against Xanthomonas axonopodis . Please get in touch with us in case you know of something that might help to fight this disease. Looking forward hearing from you.

Chemical Control

Always consider an integrated approach with preventive measures together with biological treatment if available. Apply copper based fungicides (for example copper oxychloride, 3g/l of water) at an early stage of the disease to ensure the desired effect.

Preventive Measures

Plant resistant varieties.,Use only pathogen-free seeds.,Rotate crops with non-host crops.,Avoid injuring plants during field work especially when the foliage is wet.,Make sure that your fertilization program includes potash and phosphorous.,Maintain good field hygiene.,Plough deep after harvest or remove and burn all crop residues.