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

Downy mildew.

PHOTO 41. Active, vigorous fungal growth which is representative of millions of spore-producing organs of the fungus and spores. Such situations are usually solicited after suspect downy mildew infected organs are subjected to plastic bag “incubation”.

PHOTO 42. Downy mildew shortly before and during the flowering stage.

34 • A Guide to Grapevine Abnormalities in South Africa