Why Are My Raspberry Canes Dying Suddenly Mid-Season?

A raspberry cane that was green and healthy in the spring — perhaps already producing fruit — that suddenly wilts from the tip downward and dies with brown, dead leaves still attached is showing the classic symptoms of cane blight. This is a fungal disease caused by Leptosphaeria coniothyrium that enters canes through wounds or at the junction where fruiting laterals join the main cane. It can kill individual canes rapidly and spread to neighbouring canes if not managed promptly.

Identifying cane blight

Look at the base of the dying cane, close to soil level. In cane blight, the cane tissue at the crown or just above the soil line turns dark brown to purple-black and the bark may crack or lift. The death of the cane progresses from this point upward. The wilting is rapid — within a few days of the crown infection becoming severe enough to cut off water supply. This is distinct from cane die-back from the tip downward caused by cane borer insects.

Cutting out affected canes

Cut affected canes back to below the visible discolouration — at least to healthy white wood, ideally to ground level. Disinfect secateurs between cuts with methylated spirits or dilute bleach solution; the fungal spores are easily transferred to healthy canes on unsterilised blades. Bag and bin all removed material; never compost it. In severe outbreaks, multiple canes can be affected — remove all showing symptoms and do not be tempted to leave a partially affected cane in the hope of still harvesting from it.

Why wounds are the entry point

Cane blight most commonly enters through pruning cuts, insect damage, or mechanical damage from training. Using sharp, clean secateurs that make a clean cut rather than a ragged wound reduces infection risk significantly. Pruning in dry weather when fungal spores are less mobile also helps. Autumn pruning in dry conditions is preferable to wet spring pruning for the same reason.

Varieties with better resistance

Some raspberry varieties show better tolerance to cane blight than others. If you consistently experience cane blight, consider replacing with a more resistant variety at the next replanting. Starting fresh in a new position with clean certified virus-free stock and good drainage is the most effective long-term reset.