Skip to content
Pocket Botanist
Get the app

Black Locust · Robinia pseudoacacia

Why are there spots on my Black Locust leaves?

Spots are less common for this tree and are typically caused by insect activity rather than fungal disease. Check the leaves for tiny tunnels or discoloration first.

Not sure it's this? Check a photo of your plant for free

spots on a plant
Photo: Scot Nelson, CC0

Check these first

  1. Hold a leaf up to the light to see if there are larvae inside.
  2. Check if the spots are on the outer or inner canopy.
  3. Look for tiny entry holes on the leaf surface.

Likely causes

  1. Leaf miner

    Most likely

    How to tell: You will see brown, blotchy spots or winding tunnels between the leaf surfaces. The larvae live inside the leaf and eat the tissue.

    What to do: Remove and destroy heavily infested leaves to reduce the local population. Encourage natural predators like birds and beneficial wasps to visit your garden.

  2. Sunscald

    Possible

    How to tell: Small, bleached or tan spots appear on leaves that are suddenly exposed to intense, direct sun. This often happens after a period of cloudy weather.

    What to do: There is no direct fix for the spots, but the tree will grow new, acclimated leaves. Ensure the tree is well watered to help it handle the heat.

Leaf spots on other plants

Find out what's wrong with your black locust

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.

Download on the App StoreGet it on Google Play

When to worry

If the spots cover the majority of the leaves and cause early defoliation, the tree's energy reserves will suffer. A few spots here and there are usually harmless.

Stopping it coming back

Keep the tree healthy and vigorous, as strong trees can tolerate minor leaf miner damage without long term harm.

Black Locust: spots? Check yours with a photo

Every plant is a little different. Take a photo of your black locust 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.

Download on the App StoreGet it on Google Play

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

Questions people ask

Should I use a fungicide for the spots?
No, fungicides will not help because these spots are usually caused by insects, not fungi.
Will the leaves recover?
No, the damaged tissue will not turn green again. The tree will replace the leaves during the next growth cycle.

Guides to these causes

More problems with Black Locust

Back to the Black Locust guide

This article was generated with AI on from the plant’s care profile and is general information, not horticultural advice. Read about how we build these guides.