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

Shiraz disease.

PHOTO 240. A further example of differentiation of abnormally large and atypical phloem at the expense of xylem. Note the characteristic lenticel in the 12:00 position.

PHOTO 241. Despite a courageous effort to endure by means of renewed shoot development (at the top end of the graft union), this Merlot noir grapevine finally had to succumb – in reaction to abnormalities caused by Shiraz disease.

156 • A Guide to Grapevine Abnormalities in South Africa