Phoma cajanicola
Fungus
Circular, oval and irregular or V-shaped lesions occur on leaves. Lesions are gray or tan and have a narrow, dark margin. In older lesions, there are numerous, small black specks (pycnidial bodies, means of dispersing asexual spores).
There are no biological methods known for controlling the disease successfully.
Always consider an integrated approach with preventive measures together with biological treatments if available. Applications with regulated products should be done as soon as the spots occur on the leaves.
Damage is caused by the fungus Phyllosticta cajanicola. This genus when fruiting on leaves is described as Phyllosticta while when occurring on other parts of the plant were taxonomically placed in Phoma. The fungus survives in infested crop residues and can be transmitted via seeds. Warm, humid conditions favor the development of the disease.