Vine Pests and Diseases Flashcards
What is Powdery Mildew also known as?
Oidium.
What are the indicators of Powdery mildew?
- Damages green parts of vine.
- Leaves curl and develop dull grey patches with cobweb patches on both sides of the leaf.
- Musty smelling canopy in advanced infection.
- Berries infected before veraison become covered in a grey / white velvet and drop off.
- At veraison they split down to the pips and become susceptible to other infections.
What are the conditions required for powdery mildew?
21-25°C, does not need rain only humidity and shade.
What are the prevention / cures for powdery mildew?
Canopy management to reduce leaf bunching.
Sulfur spays prevent, stop and cure the disease.
What are the indicators of Downy Mildew?
- Damage to green parts of the plant.
- Yellow oil spots on surface of leaf, with white downy patches on underside.
- Mosaic mildew common after veraison.
- Flower infections cause them to dry up and fall off.
- Berry infection causes them to go grey when young, and dry up and go brown when older.
What conditions are required for Downy Mildew?
Needs rainfall / water and warm temperatures - 18°C - for at least one hour
What are the prevention / cures for Downy Mildew?
- Canopy management to prevent leaf bunching.
- Copper salts based pesticides - Bordeaux mixture.
What are the indicators of Grey Rot?
- Leaves develop stains 2-3cm with grey felting on underside and sometimes topside.
- Berry infection is most serious. Berries go brown and sensitive to touch. If rainy dense tufts of conidia - spores - appear, if dry, infected berries shrivel up.
How is Grey Rot prevented / cured?
- Prevention is better as is hard to control once present.
- Broad spectrum fungicides also used for powdery mildew (sulfur sprays).
What is the fungus that causes Eutypa dieback called?
Eutypa Lata.
What are the indicators of Eutypa dieback?
- Symptoms often not seen in young vineyards.
- Stunted shoots with small yellow cupped leaves. Yields effected.
What conditions are required for Eutypa dieback?
- Enters through pruning wounds.
- Needs mild temperatures and moisture.
How is Eutypa dieback controlled / prevented?
- Vineyard hygiene - pruning wounds should be covered in a fungicidal paste.
- Pruning should take place in early winter when the spore numbers are low.
What are the indicators of Phomopsis?
- Noticed at winter pruning. Canes whiten and snap off easily.
- Shoots growing from infected canes develop brown patches of dead tissue.
- Leaf symtoms in USA - small dark spots after rainfall, leaves become distorted and stunted.
What conditions are required for Phomopsis?
- Spreads easily in high humidity and low temperatures - associated with damp areas with rainy cold springs.
