Plant guide:ð Grapes
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Fungal
Botrytis Bunch Rot on Grapes
Commonly affects: Vitis vinifera, V. labrusca (Grape)
A fuzzy grey mould develops on ripening berries, spreading rapidly through tightly-packed clusters, especially after rain near harvest time.
Potential Causes
- 1Botrytis cinerea fungus, favoured by humid conditions and dense fruit clusters
- 2Berries damaged by insects, birds, or splitting providing entry points
- 3Extended wet weather close to harvest
Solution Steps
- 1Thin clusters and remove leaves around fruit zones to improve airflow and light penetration
- 2Harvest promptly once fruit is ripe rather than leaving it exposed to prolonged wet weather
- 3Remove and destroy any infected berries or clusters as soon as spotted
- 4Apply a targeted fungicide during bloom and just before bunch closure if the disease is a recurring problem
Prevention Tip
Improving airflow around fruit clusters through leaf removal in the fruiting zone is one of the most effective non-chemical defences against Botrytis.
