Mildew on Currants

Symptoms

• Powdery mildew shows itself in the early summer months as a white powder-like growth on leaves, branch tips and shoots of infected currants and gooseberries. It begins as small, circular white spots that expand into a continuous flow of mildew, according to Cornell University.

Cause

• Powdery mildew is spread by fungus spores that will land on the leaves of currants and produce the visible white patches. The spores travel by the wind to other plants during times of high humidity. Indoors, the mildew can develop at any time during the year, but the rate at which it grows depends on the relative humidity level.

Treatment

• Prune away any infected leaves or twigs of the currant plants. Dispose of any debris around the plant to stop the spread of the mildew. Horticultural oils, if applied when the mildew is first noticed, can prevent the mildew from spreading.