Anthracnose

Colletotrichum

also called bean anthracnose, ripe rot

Sunken dark spots on pods, fruit and stems, often with a pink slime of spores in the center in wet weather.

Fungus Serious Rain splashSeed-borneSpread in water Spreads to neighbors

What you'll see

Sunken, dark, circular lesions on pods, fruit and stems, sometimes with a raised darker rim.
A salmon-pink, slimy mass of spores oozes from the center of older spots in damp weather.
On beans, reddish-brown streaks and cankers appear on stems, veins and pods.
Leaf spots follow the veins, turning them brown and brittle.
On ripening fruit such as tomato, apple or cucurbits, soft sunken rotted patches spread quickly.

Why it happens

A group of related fungi that carry over on infected seed, on crop debris and on mummified fruit. They spread by rain and irrigation splash and enter through the skin of leaves, pods and fruit, especially where these are wet or damaged.

Warm, wet and humid weather is ideal, and splashing rain in crowded plantings moves spores from plant to plant. Overhead watering and working among wet plants make it worse.

Treating it

Pick off and destroy affected pods, fruit and leaves as they appear.
Stop overhead watering and water at the base, keeping foliage as dry as possible.
Avoid touching or harvesting plants while they are wet to reduce spread.
Clear and destroy heavily infected plants rather than let them seed the bed.
A copper-based fungicide can protect healthy growth where the disease is established.

Keeping it away

Save or buy only clean, certified seed, and never save seed from an infected crop.
Rotate crops over three or four years and clear all debris after harvest.
Space plants for good airflow and mulch to cut down on splash.
Grow resistant varieties of beans and cucurbits where available.
Work among plants only when dry, and keep tools clean.

Who gets it

French and runner beans are classic hosts, along with cucumbers, courgettes, melons, squash and gourds, plus tomatoes and tree fruit such as apple.