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

Dead-arm.

PHOTO 52. The occurrence of longitudinal lens-shaped cracks is characteristic of dead-arm disease, so too brownish-black discolouration and tissue withering on the basal internodes of young shoots.

PHOTO 53. In highly susceptible cultivars, longitudinal cracks are often more numerous and longer and not restricted to the most basal internodes of shoots.

A Guide to Grapevine Abnormalities in South Africa • 41