Disease

Fungal leaf spot

Brown or black spots, often with a yellow halo, spread by splashing water.

What you'll see

• Round to irregular tan, brown or black spots, often with a darker edge or a yellow halo.
• Tiny black dots in the center of the spots.
• Spots merge into dead blotches, and badly spotted leaves yellow and drop.

Why it happens

Many different fungi cause leaf spots. Their spores travel in splashing water and infect leaves that stay wet.

How to fix it

1. Pick off spotted leaves and clear fallen debris from around the plant.
2. Stop wetting the leaves: water at the base, early in the day.
3. Space or thin plants so air moves between them.
4. Most leaf spots are cosmetic. On valuable plants, a copper spray can protect new leaves; use it exactly as the label says and keep kids and pets away.

Keep it from coming back

• Start with healthy plants and resistant varieties.
• Avoid misting and handling plants while their leaves are wet.
• Clean up fallen leaves in autumn.

Read more

• Watering a vegetable garden

Sources

• UC IPM: Leaf spot diseases
• Missouri Botanical Garden: Fungal spots, blights and blotches
• University of Maryland Extension: Fungal leaf spots on indoor plants

General guidance, not a diagnosis. For valuable, edible or outdoor crops, check with a local extension service or plant expert. Use any product exactly as its label says, and keep children and pets away while it dries.