🦠 Powdery mildew (oidium)
A fungus that coats leaves and berries with a white, flour-like dust.
Powdery mildew, or oidium, is a fungal disease of grapes. It covers leaves, shoots and berries with a white, dusty coating like flour. The cause is the fungus Erysiphe necator. It comes from North America and reached Europe in the middle of the 19th century, when it did great damage to vineyards.
The fungus likes moderate warmth and dry weather, unlike many other fungi that need moisture. It thrives in a dense canopy, where there is little light and air. Infected berries stop growing and split, and the crop is lost. Wine from diseased berries has an unpleasant taste.
The main protection is sulphur. It is applied as a powder or spray, and it is notable for being allowed in organic viticulture too. Good airflow through the canopy also helps, which is why leaves are thinned. There are also resistant PIWI varieties that powdery mildew hardly affects.
Powdery mildew is one of the vine diseases. It should not be confused with downy mildew, a different disease with a different cause.
What it includes
How it connects to Wine
🦠 Powdery mildew (oidium) → kind of → 🦠 Grapevine diseases → kind of → 🌿 Viticulture → kind of → 🍷 Wine
Links
- Previous step
- 🌿 PIWI grape varieties
- Next step
- 🌿 Sulphur dusting
- What it affects
- 🦠 Erysiphe necator
- Part of
- 🦠 Grapevine diseases
Frequently asked questions
What is powdery mildew on grapes?
A fungal disease that covers leaves and berries with a white, flour-like coating, caused by the fungus Erysiphe necator.
How is oidium treated?
Mainly with sulphur, as well as by thinning the canopy for airflow and by using resistant varieties.
How is oidium different from downy mildew?
They are different diseases. Oidium is powdery mildew, while downy mildew has a different cause.
What to read next
- 🌿 PIWI grape varieties — New varieties resistant to fungal diseases that need fewer sprayings.
- 🌿 Sulphur dusting — Sulphur powder against powdery mildew, an old remedy.
Similar
🦠 Anthracnose (grape) · 🦠 Downy mildew · 🦠 Black rot (grape) · 🦠 Esca · 🦠 Pierce's disease · 🦠 Flavescence dorée