Gray Mold (Botrytis)
Risk near you, next 48h
See whether your local forecast favours this disease right now.
When it strikes
Treat, then re-check in 5–7 days
Pick off the worst material, apply the organic option below, and look again after five to seven days. If the spread continued, escalate rather than repeating the same treatment.
Rain and irrigation splash
Water splashing off soil and infected leaves carries it upward and along the row. Watering at the base and mulching the soil surface break the route.
It carries over to next season in soil, debris or seed — which is why rotation matters here, not just treatment.
Keep out of the compost
This survives a garden heap. Bag it for municipal green waste, which is composted industrially at temperatures a garden heap cannot reach, or burn it where that is permitted.
When and where to look
Scout the planting while temperatures hold between 5°C and 22°C, with humidity above 90%, after rain or heavy dew, while the leaves are still wet. Risk builds after roughly 8 unbroken hours of those conditions, so the morning after such a night is the moment to look.
Rule these out first
Same category, and at least one host crop in common — so they are genuinely confusable in the same part of the garden.
The signs that lead here
Full problem lists for these crops
About
Gray mold (Botrytis cinerea) is a ubiquitous fungus attacking soft tissue of strawberries, grapes, tomatoes and ornamentals, especially in cool, damp, poorly ventilated conditions and on greenhouse crops.
Symptoms
Fuzzy grey-brown mould on flowers, fruit and stems; soft watery rot; tan spots with concentric zoning on leaves. Spores puff out in clouds when disturbed.
Organic Treatment
Remove infected tissue and spent flowers promptly, increase ventilation, and lower humidity. Spray Bacillus subtilis or copper in persistent damp weather.
Chemical Treatment
Fenhexamid, cyprodinil + fludioxonil, or boscalid, rotating chemistries because Botrytis develops resistance quickly.
Prevention
Avoid wounding fruit, harvest promptly, ventilate, reduce humidity, and avoid overhead watering in cool weather.
Crops at risk
Related problems
Gray Mold (Botrytis) risk by location
Each location has a month-by-month profile computed from the weather archive: how many hours a year actually meet this disease’s thresholds.