A Guide to Grapevine Abnormalities in South Africa - P.G. GOUSSARD

Oidium.

PHOTO 10. Hardly visible yet, but the first signs of oidium can be recognised as small, pale green spots on the upper surfaces when the leaves are held at a slant to the light.

PHOTO 11. In this instance the spots (Photo 10) are more prominent which facilitates the visual observation of oidium.

A Guide to Grapevine Abnormalities in South Africa • 17