Symptoms
- check_circleSunken, discoloured, dead patches on bark or stems
- check_circleCracks or lesions with orange or pink fungal bodies
- check_circleDieback above the canker point
- check_circleGumming or oozing from the affected area
Causes
- arrow_rightFungal pathogens (e.g. Nectria, Phytophthora) entering through wounds
- arrow_rightBacterial canker (Pseudomonas) in stone fruits
- arrow_rightPruning wounds left unprotected
- arrow_rightFrost damage creating entry points
- arrow_rightWaterlogged soil weakening root systems
How to Diagnose
Cut into the canker — dead, brown tissue beneath the bark confirms it. Healthy tissue beyond the canker is white or green. Check whether canker follows a pruning wound or frost event.
Treatment
Prune affected wood back to healthy tissue, cutting at least 10cm beyond visible discolouration. Sterilise tools between cuts. Apply wound paint to large cuts. For bacterial canker, apply a copper fungicide in autumn.
Prevention
Prune in dry weather to reduce infection risk. Sterilise pruning tools. Apply wound sealant to large pruning cuts. Avoid planting in waterlogged sites. Choose canker-resistant varieties where available.
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