Causal organism:

It is caused by Erysiphe cichoracearum DC. Outbreak of this disease is associated with dry weather.

Symptoms

Ø It attacks leaves first producing faint,

Ø slightly discolourd specks from which grayish white powdery growth of mycelium and spores spread over leaf, stem and pod.

Ø The leaves turn yellow and die.

Ø The fruits do not either set or remain very small.

Ø It causes defoliation.

The disease develops late in season and reaches to maximum intensity at the time of pod formation. The early cultivars escape the disease.