Common leaf spot of strawberry

About

A very common spotting of strawberry leaves. It is usually minor and must be severe before it cuts yield.

Also called common leaf spot, strawberry leaf spot

How to recognize it

Symptoms

Small round spots, roughly 1/16 to 1/4 inch across, start reddish-purple and develop tan to gray-white centers with a purple border. Spots can run together on heavily infected leaves.

Often confused with

Leaf scorch spots stay dark purple without a pale center; leaf blight and leaf blotch lesions spread larger and faster.

Worse when

Humid weather and long leaf wetness (12 to 18 hours or more), with temperatures of about 59 to 77°F.

How it spreads

The fungus spends the winter in old leaves and debris, and spores spread by splashing rain and overhead watering.

When

Through the growing season in wet weather.

What to do, gentlest first

Prevention works best; most sprays only protect healthy leaves and can't cure infected ones. Always read and follow the product label.

1. Plant resistant varieties Prevent

   Allstar, Earliglow and Jewell resist both leaf spot and leaf scorch, and Honeoye is tolerant.

2. Keep leaves dry and growth balanced Prevent

   Space plants, pull weeds, use drip irrigation instead of overhead watering, and avoid heavy spring nitrogen; UMass suggests splitting nitrogen between renovation time and early fall.

3. Remove old leaves and debris By hand

   Clear out dead and spotted leaves and plant debris where the fungus overwinters.

Plants it affects

Strawberry