Xanthomonas axonopodis pv. glycines
Minute, light green specks appear on one or both sides of young leaves. These specks have raised centers and later develop into small light brown or orange pustules, often situated along the leaf veins. At later stages of the disease, they fuse and form large brown irregular lesions, often with a yellow halo. 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.
The symptoms are caused by Xanthomonas axonopodis pv. glycines. It is a seedborne bacterium that can also overwinter in crop residues in the soil. It is carried by the wind, water droplets or insects and enters the plant through natural openings or mechanical injuries. The disease rather occurs early in the season, but later infections are also possible. It 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.
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.
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.