No seed treatment is recommended. B. Ascospores produced by perithecia on stubble are blown by wind and rain to infect seedlings. C. Pycnidia form in lesions on seedlings. As the crop grows, conidiospores from pycnida spread the disease in the canopy by rainsplash. E. Disease infested stubble remains after harvest.
Infected seed is harvested with healthy seed.
Alternaria and cercospora Alternaria and cercospora are widespread but minor diseases throughout the agricultural area and can be mistakenly identified as ascochyta blight. Alternaria spots have a red-brown margin and contain obvious concentric rings. Cercospora spots are darker and have irregular edges. They may develop a ring pattern inside the spot. Both diseases can be separated from ascochyta blight as the spots do not develop black fruiting bodies on a grey centre.