Disease in Grapes
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Angular Leaf scorch
Fungal.
Most likely to become a problem in years when high rainfall occurs between bud break and early summer.
Black rot
Fungal.
Rain triggers the release of overwintering spores in canes and mummified berries.
Botrytis
Fungal.
Can cause severe economic loss in tight-clustered French varieties and Vitis vinifera cultivars and clones.
Crown gall
Bacterial.
Mostly form on trunks where injury occurs.
Downy Mildew
Fungus-like.
Only grows on the underside of the leaf.
Eutypa dieback/ botryosphaeria dieback
Fungal.
New shoots above cankers often appear stunted, with shortened internodes, and bear small, cupped, greenish yellow leaves in the spring.
grapevine leafroll disease
Virus.
Spread through vineyards by phloem feeding insects and the sale of infected nursery material.
Phomopsis cane and leaf spot
Fungal.
Hedged vineyards are at a particular risk of incurring economic losses, although serious problems occur regularly in hand-pruned vineyards when conditions are favorable.
Powdery mildew
Fungal.
Can grow on both sides of a leaf.
For more information on disease control, check out the following podcasts:
Powdery Mildew (Podcast 26)
Powdery Mildew (Podcast 30)