Brown rot: identify, prevent, control

Updated October 2026

Worst when flowering or the last month before harvest is wet and humid, from September flowering to summer harvest.

Brown rot is the most common fruit rot of peaches, nectarines, plums, apricots, cherries and almonds in Australia. The fungus attacks blossoms in spring, can kill twigs, and then rots fruit as it ripens, leaving shrivelled mummies that carry the disease into next season. Good hygiene and well-timed sprays in wet years keep it under control.

Monilinia fructicola, Monilinia laxa

How to identify it

• In spring, infected blossoms turn brown, wither and stay stuck on the twig instead of falling, often with a little gum at the base.
• From a blighted flower the infection can run into the twig, forming a sunken, gummy canker that may girdle and kill the twig so its leaves wilt.
• On ripening fruit a small, round, light brown spot spreads quickly into a firm brown rot covering the whole fruit within days.
• The rotted skin soon becomes covered in powdery, fawn to grey tufts of spores, often in rings.
• Rotted fruit dries into a shrivelled, dark mummy that hangs on the tree or lies on the ground through winter.
• On loquats and almonds you may see the same blossom blight and fawn spore tufts on fruit or hulls.

What it is often confused with

When and where it is worst

Brown rot occurs in every state but is worst where rain falls at flowering or close to harvest, such as the coast and ranges of New South Wales, Victoria, the Adelaide Hills, Tasmania and South East Queensland. It is less of a problem in dry inland districts and in Perth, where summers are dry. Cherries, apricots, peaches, nectarines and plums are all hit, and almonds and loquats can also carry it.

The fungus survives winter in mummified fruit, old blossom stalks and twig cankers. Spores are released in wet weather at flowering in late winter to spring, and blighted flowers keep producing spores right through to harvest. Fruit becomes much more susceptible as it ripens, so a warm, humid or rainy spell in the month before picking, often November to February, can cause big losses. Fruit split by rain, pecked by birds or damaged by insects such as Carpophilus beetles rots first.

Plants it affects

These plants in our library list it as a problem to watch for.

How to prevent it

• In winter, pick every mummified fruit off the tree and the ground, cut out cankered twigs, and bin or bury them rather than composting them.
• Prune to an open vase shape so blossoms and fruit dry quickly after rain.
• Thin fruit so they do not touch, because rot spreads quickly between touching fruit.
• Avoid overhead watering, especially from flowering to harvest.
• Control birds, earwigs, fruit fly and beetles that wound fruit, and pick up fallen fruit during harvest.
• Pick fruit promptly when ripe and refrigerate it, removing any rotting fruit straight away.

Organic control, step by step

• Do the winter clean-up thoroughly, because removing mummies cuts the main source of spores.
• Cut out blighted blossoms and twigs in spring as soon as you see them.
• A copper or lime sulphur spray at bud swell reduces early infection; check the product label lists stone fruit and the timing.
• If rain is forecast during flowering or in the month before harvest, a sulphur-based or other organic-approved fungicide whose label lists brown rot can add protection.

Conventional control

• Mancozeb is used in home garden fungicides for brown rot on stone fruit; apply at bud swell, at full bloom and petal fall, then about every three weeks until the label's withholding period before harvest.
• In wet seasons a spray about a month before harvest and another two weeks later protects ripening fruit; check the product's withholding period fits your picking date.
• Do not rely on the same fungicide group every time, to slow the build-up of resistance.
• Read the label, check the crop is listed and keep to the withholding period before you pick fruit.

Frequently asked questions

Related problems

Sources: Agriculture Victoria, Brown rot of stone fruits; Yates Australia, Brown rot. Identification and control follow these sources. Always read the product label before use.