Will walnut blight kill my tree?

It rarely kills a mature tree, but it can significantly reduce your nut harvest. It is mostly a cosmetic and production issue.

Can I eat the nuts if the tree has blight?

Yes, the nut meat inside is usually fine if the husk is not fully compromised. Just inspect the shell for staining or rot.

English walnut: spots, causes and fixes

Check these first

Inspect the leaves for a yellow halo around the black spots.
Check if the spots are appearing on the fruit husks as well.
Look for signs of moisture buildup in the lower canopy.

Likely causes

Walnut Blight
Most likely
How to tell: You will see small, water soaked spots that turn black and necrotic on leaves, stems, and fruit. The spots often have a yellow halo around them.
What to do: Prune out heavily infected branches during dry weather to stop the spread. Apply a copper based fungicide spray in the early spring when buds begin to break to protect new growth.
Anthracnose
Possible
How to tell: This fungal disease creates brown or black spots that may merge to cover large parts of the leaf. It usually appears during late summer after a wet season.
What to do: Rake up and destroy all fallen leaves in the autumn to remove fungal spores from the soil. Keep the canopy thinned to improve airflow and reduce moisture buildup.

Leaf spots on other plants

Find out what's wrong with your english walnut

The list above covers the usual causes. Pocket Botanist looks at a photo of your actual plant and tells you the likely cause, how serious it is, and what to try first. Identification and a health check are free.

When to worry

If the spots cover most of the foliage or cause premature nut drop, it is serious. A few spots are normal in very wet years.

Stopping it coming back

Keep the area under the tree clean of debris and ensure the tree has plenty of space for air to circulate.

English walnut: spots? Check yours with a photo

Every plant is a little different. Take a photo of your english walnut and Pocket Botanist tells you which cause is most likely, how serious it is, and what to try first. A few checks a day are free. Save the plant and you get care reminders timed for it.

Get the app · Or check it from a photo now, free

Questions people ask

Will walnut blight kill my tree?: It rarely kills a mature tree, but it can significantly reduce your nut harvest. It is mostly a cosmetic and production issue.
Can I eat the nuts if the tree has blight?: Yes, the nut meat inside is usually fine if the husk is not fully compromised. Just inspect the shell for staining or rot.

Guides to these causes

Anthracnose

Why are there black spots on my English walnut leaves?

Check these first

Not sure what's wrong with your english walnut?