If you’re seeing dark, sunken spots or blotches on leaves, stems, or fruit—often spreading quickly in wet weather – anthracnose may be the cause.
Overview
Anthracnose is a group of fungal diseases
It causes spots, lesions, and tissue damage
It can affect leaves, stems, shoots, and fruits
Common Signs
Small brown or black spots on leaves
Spots become sunken or depressed
Lesions may expand and merge
Leaves may yellow, curl, or drop early
Fruit may develop sunken, rotting spots
Often Confused With
Leaf spot
→ flatter spots, less sunken
Black spot
→ more defined circular spots with halos
Blight
→ larger dead patches, faster spread
Anthracnose often has sunken lesions and irregular damage
Plants Commonly Affected
Tomatoes, peppers, and beans
Cucumbers and squash
Trees (oak, maple, sycamore)
Many ornamentals
Occurrence
Thrives in cool to warm, wet conditions
Spreads through water splash, rain, and debris
Often worse in rainy seasons
Can survive in fallen leaves and plant debris
Fast Control (Start Here)
Remove infected leaves and plant parts
Clean up debris around plants
Avoid working with wet plants
Improve airflow
Which Treatment Should You Use?
For early signs
→ Remove affected areas and reduce moisture
For ongoing risk
→ Use preventative fungicide if needed
For widespread damage
→ Focus on sanitation and prevention
→ Fungicides protect new growth, not damaged areas
Instructions
Immediate Action
Remove infected leaves, stems, or fruit
Dispose of infected material
Clean tools after use
Environmental Control
Avoid overhead watering
Water at the soil line
Improve drainage and airflow
Keep foliage dry
Prevention
Remove fallen leaves regularly
Rotate crops
Plant in well-drained soil
Use resistant varieties when possible
Avoid handling plants when wet
When to Remove Plants
Mild infection
Remove affected parts
Monitor closely
Severe infection
If large portions are affected or fruit is rotting
Consider removing plant
If You Pull Plants: Compost or Trash?
Do not compost infected material
Discard in trash
Can You Plant Again in the Same Space?
Not immediately
Remove debris and rotate crops
Fungus can persist in soil and plant material
Gardener’s Notes
Anthracnose spreads quickly in wet weather
It affects many plant types
Early cleanup is very effective
Key Takeaway
Look for sunken lesions, not just spots
Remove infected material early
Keep foliage dry
Focus on prevention and cleanup
