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

Aster Yellows.

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PHOTO 261. In South Africa Aster Yellows disease are believed to be transmitted by leafhoppers (as sucking, phloem-feeding insects) from affected plants (which may include weeds and vegetables) to healthy plants (grapevines).

PHOTO 262. Characteristic of Aster Yellows disease is the occurrence of seriously delayed bud burst and dwarfed shoot growth on parts of grapevines – with an additional tendency to develop numerous water shoots (on trunk parts especially).

170 • A Guide to Grapevine Abnormalities in South Africa