Brown rot is the disease that turns a perfect peach, plum, or cherry soft and brown almost overnight. It starts as a small brown spot on the fruit, often where an insect has fed or where two fruit are touching, and it spreads rapidly until the whole fruit is soft, brown, and covered in small tan tufts of spores. The fruit then either drops or shrivels into a hard, black mummy that hangs on the tree all winter, carrying the disease into the next year. A tree that is badly hit can lose most of its crop, and the fruit that survives is often infected too, rotting in storage within days of picking.

The fungi are Monilinia species, and they attack stone fruit above all — peaches, plums, cherries, apricots, and nectarines — though they can also affect apples, pears, and other fruit. The disease has two stages: a blossom blight in spring, when the flowers brown and die, and a fruit rot in summer, when the ripening fruit rots. Both stages need wet weather, and both are spread by spores that travel on the wind and in rain. The control is a combination of thinning the fruit, removing mummies, improving airflow, and harvesting promptly — all aimed at breaking the cycle between the blossom stage and the fruit stage.

What brown rot fruit looks like: symptoms

  • Soft brown rot on fruit: a brown, soft, spreading rot on ripening fruit, often starting at a wound or where two fruit touch, that covers the whole fruit in a few days.
  • Tan spore tufts: small, tan or greyish tufts of spores on the surface of the rotted fruit, often in concentric rings, which are the most distinctive sign.
  • Blossom blight: flowers turn brown, shrivel, and hang on the tree in spring, often with a grey mould on them, and the twig beyond the flower may die back.
  • Twig cankers: sunken, dark cankers on the twigs where the blossom blight has spread, which can girdle the twig and kill it.
  • Mummified fruit: fruit that rots and then dries into a hard, black, shrivelled mummy that hangs on the tree or falls to the ground, carrying the fungus through winter.
  • Fruit that rots in storage: fruit that looked clean at picking can develop brown rot in storage within days, especially if it was bruised or if it was picked wet.
  • A tree that loses its crop: in a bad year, most of the fruit on a tree can rot before it ripens, and the tree is left with mummies and dead twigs.

Brown rot starts in spring, with the blossom blight: the flowers brown and die, and the fungus spreads into the twig. The disease then goes quiet for a few weeks while the fruit is small and green, and it returns with a rush as the fruit ripens, when the sugar content rises and the skin softens. A single rotting fruit can infect every fruit it touches, and in warm, wet weather the rot can take a whole cluster in days. The mummies that form then carry the fungus through winter, and in the following spring they produce the spores that start the blossom blight again. The yearly cycle is very regular, which is why a tree that had brown rot this year will almost certainly have it next year unless the mummies are removed.

Which plants get brown rot fruit

Brown rot attacks stone fruit: peaches, nectarines, plums, cherries, apricots, and almonds, along with apples, pears, and quinces in some forms. Peaches and sweet cherries are among the most susceptible, and the disease is worst in warm, humid climates and in rainy summers. It does not attack vegetables or ornamentals, so it is a problem for the fruit trees alone. Young trees are hit as hard as old ones, and the disease is worst on trees with dense canopies where the fruit stays wet and where fruit touch each other.

Conditions that favour brown rot fruit

Brown rot needs warm, wet weather: temperatures in the 70s Fahrenheit with rain or heavy dew, especially while the blossoms are open and while the fruit is ripening. The fungi enter through wounds — insect feeding, bird pecks, hail, and cracks from rain — and through the flowers in spring. Crowded, dense canopies that dry slowly are hit hardest, and fruit that touches other fruit is the most vulnerable. The fungi overwinter in mummified fruit and in twig cankers, so a tree that was not cleaned up in autumn starts the spring with the disease already present. Warm, humid nights that keep the fruit wet are particularly dangerous.

How brown rot fruit spreads

Brown rot spreads by spores that travel on the wind, in rain splash, and on insects, and by direct contact between a rotting fruit and a healthy one. The tan spore tufts on a rotted fruit release enormous numbers of spores, and a single mummy can infect a whole tree in spring. The fungi also travel in infected nursery stock, though this is less common than the carryover from mummies and cankers on the tree itself. The practical rule is that the mummies are the source, and removing them is the control — a tree with no mummies and no cankers starts the spring with far less disease.

How to tell it apart from lookalikes

Brown rot is sometimes confused with other fruit rots, but its soft brown rot with tan spore tufts, and its habit of mummifying the fruit on the tree, are distinctive. Anthracnose makes sunken, dark spots with pinkish spore masses rather than a soft brown rot. Botrytis gray mold makes a grey, fuzzy mould on soft fruit, while brown rot makes a brown rot with tan tufts. Bacterial spot makes small, raised, scabby spots rather than a spreading soft rot. If the fruit is soft, brown, and covered in tan tufts, and it shrivels into a mummy that hangs on the tree, brown rot is the most likely answer.

Prevention: cultural steps that work

  • Thin the fruit so it does not touch other fruit and air can move between the remaining fruit.
  • Prune for an open canopy so the tree dries quickly after rain and the fruit is not crowded.
  • Remove and dispose of all mummified fruit from the tree and the ground in autumn and winter, and do not compost diseased material.
  • Prune out twig cankers in late winter, cutting back to clean wood, and dispose of the prunings.
  • Control insects that wound the fruit, since wounds are the main entry point for the rot.
  • Harvest fruit as soon as it ripens, handle it gently so it is not bruised, and pick it in dry weather.
  • Feed moderately and avoid heavy nitrogen that pushes soft growth and dense foliage.

Treatment step by step

  1. Pick off rotting fruit as soon as you see it, handling it gently so the spores do not spread, and dispose of it with household waste — do not compost it and do not leave it on the ground.
  2. Prune out twig cankers and dead shoots, cutting back to clean wood, and dispose of the prunings.
  3. Thin the remaining fruit so it does not touch, and improve airflow by pruning out crowded growth.
  4. Harvest the remaining fruit promptly, even if it is slightly underripe, since ripe fruit left on the tree is the most vulnerable.
  5. If you choose to spray, a fungicide labelled for brown rot on the fruit in question can protect the blossoms and the fruit, but it must be applied at bloom time and as the fruit ripens, and it will not cure fruit that is already rotting. Apply it exactly as the label directs.
  6. In autumn and winter, remove every mummy from the tree and the ground, and prune out any cankers, so the tree starts the spring clean.
  7. Store harvested fruit in a cool, dry place, and check it regularly, removing any fruit that starts to rot before it infects the rest.

What recovery looks like

Recovery from brown rot is a next-season matter: a tree that is cleaned up in autumn, pruned in winter, and thinned in spring will often produce a clean crop the following year, even if it lost most of its fruit the year before. The recovery is visible in the spring blossoms — a tree with no blossom blight and no cankers is on the way back — and in the summer fruit, which should ripen without the soft brown rot. The tree itself is rarely badly damaged by brown rot in a single year, though repeated severe blossom blight can kill twigs and weaken the tree over time. The sign that the plan is working is a harvest with no rotting fruit on the tree and no mummies left at the end of the season.

When a plant is beyond saving

A tree is rarely beyond saving from brown rot alone, because the disease attacks the blossoms and the fruit, not the roots or the trunk. A tree is in serious trouble only when blossom blight kills most of the twigs year after year, when cankers cover the branches, and when the tree fails to leaf out properly in spring. Even then, a hard prune, a thorough cleanup, and a season of good care can often revive it. The time to replace a tree is when it is a very susceptible variety in a warm, humid climate where brown rot returns every year despite thinning and cleanup — in that case, a resistant variety in a sunnier, airier position is the better investment.

Frequently asked questions

Can I eat fruit with brown rot?

No. Cut away the rotten part is not enough on a soft fruit, because the rot spreads invisibly through the flesh. Discard any fruit with brown rot, and do not eat fruit that was touching a rotten one unless it is completely clean.

Will brown rot kill my peach tree?

Rarely on its own, though severe blossom blight repeated over several years can kill twigs and weaken the tree. The main loss is the crop, not the tree.

Why does brown rot come back every year?

The fungus overwinters in mummified fruit and in twig cankers, so it is already on the tree when spring arrives. Removing every mummy and pruning out the cankers in winter is the way to break the yearly cycle.

Can I compost mummified fruit?

No. Home compost rarely gets hot enough to kill the fungus, so composting mummies returns the disease to the orchard. Bag the mummies and put them with household waste.

Should I spray for brown rot?

Spraying can help on a susceptible variety, but it must be timed to the blossom period and to fruit ripening, and it never cures fruit that is already rotting. Thinning, cleanup, and prompt harvest are the foundation, and any spray is an addition to them, used as its label directs — and check your local extension service for the best timing in your area.

Getting help and going further

If you are unsure which disease you are dealing with, take clear photos of the symptoms and check your local extension service — they can confirm a diagnosis from a sample and advise on the varieties and the timing that work best in your area. You can also try our plant disease checker to narrow down the problem, and browse the guides hub for related disease guides. For growing advice, see growing peaches. For growing advice, see growing apples. For growing advice, see zone 5 peaches. Related guides: fire blight, apple scab, botrytis gray mold. Whenever you remove diseased material, dispose of it with household waste — do not compost diseased material, since home compost rarely gets hot enough to kill the organisms that cause these diseases. Good record-keeping helps too: note the date, the weather, and the variety when a problem first appears, so you can spot the pattern next year and act earlier.