Phoma blight

Caused by: Phoma macdonaldii
Problem Category: Fungal Disease
Symptoms: Symptoms of the disease develop after flowering; large black lesions appear on stem and coalesce to form large blackened areas; dark colored irregularly shaped lesions appear on leaves and flowers; early infections can cause flowers to die; infected plants die prematurely and produce little seed; disease often affects plants in a circular pattern in the field
Comments: Fungus survives in seeds or sunflower debris in the field; disease emergence favors periods of wet weather during flowering
Management: Rotate crop to a non-host (e.g. small grains) a period of 4 years; plant hybrids which are more tolerant of the disease; control stem weevil populations in sunflower fields
Control: spray 2 times Cowdung+Asafoetida solution in 10 days interval.