Pocket BotanistCheck these first
- Look for tunnels inside the leaves.
- Inspect the twigs for small bumps.
- Check for sticky residue on the leaves.
Likely causes
Leaf miner larvae
Most likelyHow to tell: You will see white or brown winding tunnels inside the leaf tissue.
What to do: Clean up all fallen leaves in the fall to break the pest life cycle. Encourage natural predators like birds and parasitic wasps in your garden.
Scale insects
PossibleHow to tell: Small bumps on the twigs or undersides of leaves that look like tiny shells.
What to do: Scrub the branches gently with a soft brush and soapy water. Use horticultural oil in early spring to smother the eggs.
When to worry
Leaf miners rarely kill a tree, but they can make it look brown by midsummer. Treat if the infestation is severe enough to cause total defoliation.
Stopping it coming back
Maintain tree health with proper watering and mulch to help it resist pest damage.
Not sure which one it is? Photograph your horse chestnut.
This page lists the usual causes. Pocket Botanist looks at your actual leaf and tells you the likely cause, how serious it is, and what to try first. Identification and a health check are free.
Questions people ask
- Can I use systemic pesticides?
- Systemic pesticides are generally discouraged for large trees due to the risk to pollinators. Stick to cultural controls.
- Will the tree recover next year?
- Yes, the tree will grow a fresh set of leaves in the spring. The pests do not usually cause permanent damage.
More problems with Horse chestnut
Back to the Horse chestnut guide
This article was generated with AI from the plant’s care profile and is general information, not horticultural advice. Read about how we build these guides.