Anthracnose

About this condition

A fungal disease causing dark brown to black lesions on leaves and stems. It tends to occur during hot, humid periods and can spread to neighboring leaves if left unmanaged.

Common symptoms

Brown to dark brown lesions may appear on leaves, often with a yellow border
Small dark specks (spore masses) may be visible within lesions
Lesions may enlarge and merge, discoloring large portions of the leaf
Symptoms may spread to neighboring leaves or nearby plants

Common causes

Hot, humid growing conditions (most common during the rainy season and summer)
Water splashing onto foliage during watering, dispersing fungal spores
Fungal entry through pruning wounds or physical damage to leaves
Re-infection from fallen diseased leaves or plant debris left at the base

Prevention (growing conditions & routine care)

Water at the soil level to minimize water contact with foliage. Remove fallen leaves and debris from around the base of the plant. Maintain good air circulation and avoid overcrowding.

When to see a vet

Consider acting within a few days

What can a nursery or grower do?

Specialist nurseries and growers can help assess lesion appearance to identify the disease, advise on proper disposal of removed leaves, and suggest management adjustments for hot and humid seasons.

Related columns

The same problem in other plants

AgaveAnthracnose (Leaf Black Spots)