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

Bacterial blight.

PHOTO 151. Bacterial blight in White Muskadel. Although desiccation of leaves (11:00-position) from the edges inwards is characteristic, the yellowish division between necrotic tissue and normal green sections is less prominent. Direct infection through the stomata occur in the leaf just below the one mentioned above. Also note the incidence of erinose – which obviously has nothing to do with bacterial blight.

PHOTO 152. A typical example of desiccating leaves in a red grape cultivar in reaction to bacterial blight infection. Note the bright brown colour of necrotic tissue separated from normal green parts by a red edge.

A Guide to Grapevine Abnormalities in South Africa • 101