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

Potassium deficiency (470); magnesium deficiency (471).

PHOTO 470. A further example where potassium deficiencies are associated with browning/withering of older leaves, which may thus contribute to premature leaf losses.

PHOTO 471. Intravenous leaf yellowing in white grape cultivars is considered characteristic of magnesium deficiencies.

302 • A Guide to Grapevine Abnormalities in South Africa