Apple Canker
Risk near you, next 48h
See whether your local forecast favours this disease right now.
When it strikes
Remove affected material now
Take out the affected leaves, shoots or whole plants before the next wet spell, bag them as you cut, and wash your hands and tools before touching healthy plants.
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 20°C, with humidity above 85%, after rain or heavy dew, while the leaves are still wet. Risk builds after roughly 6 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
European canker (Neonectria ditissima) is the most damaging bark disease of apples and pears in a wet climate. It enters through leaf scars, pruning cuts and scab lesions in autumn rain, and then girdles and kills the wood above the infection point.
Symptoms
Elliptical sunken patches of dead bark, often centred on a bud or wound, with the bark flaking away in concentric rings. Shoots above a girdling canker die back. White pustules appear on cankers in summer and red-orange ones in winter.
Organic Treatment
Cut cankered shoots out 15 cm below the visible damage and pare larger trunk cankers back to clean wood, disinfecting tools between cuts. Prune only in dry weather, and burn all the prunings.
Chemical Treatment
A copper spray at 50% leaf fall and again at complete leaf fall protects the fresh leaf scars, which are the main infection route. Wound paints containing a fungicide help on large cuts.
Prevention
Improve drainage — canker is far worse on heavy, wet soil. Choose resistant varieties, avoid excess nitrogen, control scab (its lesions are entry wounds), and never leave pruning stubs, which cannot heal over.
Crops at risk
Related problems
Apple Canker 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.