White powdery patches appear on leaves and other green parts which later become dull colored. These patches gradually increase in size and become circular covering the lower
surface also.

When the infection is severe, both the surfaces of the leaves are completely covered by whitish powdery growth. Severely affected parts get shriveled and distorted.

In severe infections, foliage becomes yellow causing premature defoliation. The disease also creates forced maturity of the infected plants which results in heavy yield losses.

The pathogen has a wide host range and survives in oidial form on various hosts in off-season.

Secondary spread is through air-borne oidia produced in the season.