Fire blight
A bacterial disease of apples, pears and related plants that makes blossoms, shoots and branches look scorched by fire.
Also known as: Erwinia amylovora
Symptoms and identification
Flowers wilt and turn brown or black, and young shoots die back with a characteristic "shepherd's crook" bend at the tip. Leaves stay attached but look burnt. Sunken cankers form on branches and may ooze in wet weather.
Causes
Bacteria spread in warm, wet weather during flowering, carried by rain, insects and pruning tools.
Organic treatment
Prune out infected shoots at least 20–30 cm below visible damage in dry weather, disinfecting tools after each cut, and destroy the prunings. Copper sprays at blossom time can reduce infection.
Prevention
Choose resistant varieties, avoid heavy nitrogen feeding, and disinfect tools between cuts.
Chemical treatment (use with care)
Use a product labelled for fire blight at bloom, following local advice and the label.