Brown rot

What you see

Fruit develops a soft brown patch that spreads until the whole fruit is rotten, with concentric rings of buff-grey pustules on the surface. Rotten fruit dries and hangs on the tree all winter as a hard black mummy. Blossom and twigs wilt and blacken in spring.

Conditions

Warm and wet at flowering and again at ripening. It enters through any break in the skin - bird peck, wasp hole, split from rain, or fruit rubbing on fruit.

Treatment

Remove every rotten fruit and every mummy from the tree and the ground, and bin them - the mummies are the entire source of next year's infection. Cut out blighted twigs 15 cm into clean wood.

Prevention

Thin fruit so none touch. Control wasps and codling moth, which make the entry wounds. Prune for an open, fast-drying canopy. Copper at bud burst helps in a wet spring.

Months: April, May, June, July, August, September

Plants

Peach, Nectarine, Plum, Apricot, Cherry, Apple, Pear, Almond

Remedies

Bordeaux mixture (copper), Pheromone traps, Kaolin clay film

The thing people get wrong

The mummified fruits still hanging in the tree in January are not untidiness, they are next year's epidemic sitting in storage - each one releases spores directly onto the blossom below it in spring. Picking off every mummy in winter is the single highest-value hour you will spend on a stone fruit tree, and almost nobody does it.