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

1 PLANT MATERIAL PROBLEMS________________________________________ 8 2 FUNGAL DISEASES ________________________________________________ 14 2.1 Oidium ____________________________________________________ 16 2.2 Downy mildew ______________________________________________ 28 2.3 Dead-arm disease____________________________________________ 40 2.4 Anthracnose ________________________________________________ 47 2.5 Botrytis (grey rot) ___________________________________________ 53 2.6 Sour rot and blue-green / black moulds _______________________________62 2.7.1 Fungal diseases associated with wood and root rotting/dieback _______ 70 2.7.2 Fungal diseases associated with wood and root rotting/dieback _______ 81 3 BACTERIAL DISEASES______________________________________________ 94 3.1 Bacterial blight ______________________________________________ 95 3.2 Crown gall ________________________________________________ 103 4 VIRUS AND VIRUS-LIKE DISEASES __________________________________ 110 4.1 Fanleaf____________________________________________________ 112 4.2 Leafroll ___________________________________________________ 120 4.3 Stem grooving and corky bark ( rugose wood complex) ______________ 136 4.4 Shiraz disease ______________________________________________ 146 4.5 Shiraz decline ______________________________________________ 157 4.6 Fleck and enation ___________________________________________ 161 4.7 Aster Yellows ______________________________________________ 169 5 GRAPEVINE PESTS________________________________________________ 177 5.1 Phylloxera, margarodes and nematodes __________________________ 178 5.2 Snout beetles and long-horned grasshoppers _____________________ 186

6 • A Guide to Grapevine Abnormalities in South Africa