Will these pests kill my tree?

The locust borer can kill young or stressed trees over time. Leaf miners are generally just an eyesore and rarely fatal.

Should I spray my tree?

Avoid spraying unless a professional confirms a severe borer infestation. Many sprays do more harm to the environment than good for the tree.

Black Locust: pests, causes and fixes

Check these first

Inspect the trunk for small holes or piles of sawdust.
Look at the leaves for irregular brown blotches.
Check if the tree is showing signs of stress like thinning branches.

Likely causes

Locust Borer
Most likely
How to tell: You will see small entry holes on the trunk and fine sawdust, called frass, collecting at the base of the tree.
What to do: Keep the tree healthy with consistent water during dry spells to help it resist attacks. If the infestation is severe, consult a local arborist about systemic treatments, but avoid heavy pesticide use that kills beneficial insects.
Leaf Miner
Possible
How to tell: Leaves will show brown, blotchy patches where the larvae have eaten the tissue between the leaf surfaces.
What to do: Rake up and destroy fallen leaves in the autumn to break the insect life cycle. Most healthy trees can tolerate this damage without needing chemical intervention.

Pests 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.

When to worry

Worry if you see large branches dying back or if the tree trunk looks hollowed out. Minor leaf miner damage is usually just cosmetic.

Stopping it coming back

Maintain tree vigor through proper watering during the first year and avoid wounding the bark with lawn equipment.

Black Locust: pests? 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.

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

Questions people ask

Will these pests kill my tree?: The locust borer can kill young or stressed trees over time. Leaf miners are generally just an eyesore and rarely fatal.
Should I spray my tree?: Avoid spraying unless a professional confirms a severe borer infestation. Many sprays do more harm to the environment than good for the tree.

Guides to these causes

Leaf Miners

Why are there holes in my Black Locust tree?

Check these first

Not sure what's wrong with your black locust?