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

Dead-arm.

PHOTO 58. Petioles infected with dead-arm disease may cause vascular bundles to be affected, to the extent that certain parts of the leaf wither.

PHOTO 59. Dead-arm disease on leaves is associated with the occurrence of small, black spots (surrounded by pale yellow/white circles) which, in numerous quantities, cause abnormal characteristics of the leaves.

44 • A Guide to Grapevine Abnormalities in South Africa