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

Phylloxera.

PHOTO 278. Typical of phylloxera is the occurrence of: (i) hook-like galls/thickening (nodositites) especially on the tips of young, fine feeding roots and (ii) protruding galls (tuberositites) on older roots. Note the black corkiness which gradually invades the affected roots – as illustrated in the 10:00 position.

PHOTO 279. In this situation practically the entire root system of the grapevine has been destroyed by phylloxera. Note the black corky appearance of the older roots especially, as in Photo 278. A characteristic tuberosity can be seen in an older root (15:00 position).

182 • A Guide to Grapevine Abnormalities in South Africa