🦠 Sour rot
Spoilage of split berries with a vinegary smell, spread by fruit flies.
Sour rot is a grape disease in which split berries spoil and smell of vinegar. It is not a single disease but a mix of processes: yeasts and acetic acid bacteria get into a damaged berry, and the juice begins to ferment right on the bunch.
First a berry cracks. Causes vary: rain, hail, mistakes in care, tight bunches where berries press on each other. Then the flesh darkens and turns brown, and juice leaks out. The main carriers are fruit flies, which are drawn by the smell and move microbes from berry to berry.
Such rot is dangerous because its compounds get into the wine and spoil the taste. Acetic acid gives the smell of vinegar and solvent. For this reason sick bunches are removed at harvest. Protection includes loose bunches, leaf removal, control of flies and correct harvest timing. Sour rot should be told apart from noble rot: that one also lives on the berry but gives sweet wines.
Links
- Next step
- 🦠 Spotted-wing drosophila
- What it affects
- 🍷 Acetic acid bacteria
- Part of
- 🦠 Grapevine diseases
Frequently asked questions
What is sour rot?
Spoilage of split grape berries with a vinegar smell, as yeasts and acetic bacteria get in.
Who spreads sour rot?
Mainly fruit flies, and also wasps and other insects.
How is sour rot different from noble rot?
Noble rot gives sweet wines, while sour rot spoils the grapes and the taste of the wine.
Similar
🦠 Anthracnose (grape) · 🦠 Black rot (grape) · 🦠 Esca · 🦠 Pierce's disease · 🦠 Flavescence dorée · 🦠 Grapevine leafroll