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

Oidium.

PHOTO 16. Severe oidium infection later in the season may comfortably be associated with this example. Also note the typical powdery spots (already looking darker in colour) on the petioles.

PHOTO 17. A typical example of the occurrence of irregular, superficial oidium spots on young, green shoots.

20 • A Guide to Grapevine Abnormalities in South Africa