Brown rot
A fungal disease of stone and pome fruit that turns ripening fruit into soft brown rot covered in rings of grey-buff spore pustules.
Also known as: Monilinia fruit rot, Blossom wilt
Symptoms and identification
A small brown spot on a ripening fruit spreads quickly until the whole fruit is brown and soft, with concentric rings of greyish-yellow spore tufts. Rotten fruit shrivels into hard, wrinkled mummies that cling to the tree. Blossoms can wilt and turn brown, and the infection may move into the twig.
Causes
The fungus overwinters in fruit mummies and cankered twigs. Wet weather at blossom and ripening spreads spores, and wounds from birds, insects, hail or cracking give a way in.
Organic treatment
Cut out infected twigs back to healthy wood and bin all rotten fruit. A copper spray at bud swell and sulphur sprays near blossom may reduce infection.
Prevention
Pick up fallen fruit and remove every mummy from the tree in winter. Prune to open the canopy for airflow, thin fruit so they do not touch, and control codling moth, birds and other pests that wound fruit.
Chemical treatment (use with care)
Use a fungicide labelled for brown rot on that fruit, timed at blossom and before harvest as the label allows.