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

Oidium.

PHOTO 14. In addition to the white powderiness, the development of purplish, brown-black discolourations may be observed here.

PHOTO 15. Intense leaf infection results in the rapid necrosis of leaf parts, whereby the processes involved in early leaf fall are initiated.

A Guide to Grapevine Abnormalities in South Africa • 19