Pest identification
What's eating my japanese maple?
Aphids
Signs: Tiny insects cluster on shoot tips and leaf undersides, causing curled, distorted, and sticky new growth; heavy infestations produce sooty mould on bark and leaves.
Control: Blast off with a strong jet of water — do not use horticultural oils on Japanese maples as leaf damage can result. Encourage natural predators (ladybirds, lacewings). Prune out heavily infested shoot tips.
Scale insects (Japanese maple scale / horse chestnut scale)
Signs: Oyster-shell-shaped or cottony crusts on bark and undersides of branches; sap-feeding reduces vigour, causing dieback and yellowing leaves in heavy infestations.
Control: Apply horticultural oil spray in late winter/early spring before buds break to smother overwintering scale. Time follow-up sprays to catch crawler stage. Remove dead wood.
Acer gall mites (Aceria pseudoplatani)
Signs: Microscopic mites cause small red or green pimple galls on upper leaf surfaces; alarming in appearance but rarely cause lasting damage to an established tree.
Control: No treatment normally needed — galls are cosmetic. Remove affected leaves if aesthetics matter. Ensure good tree vigour through watering and mulching.
Keep japanese maple pest-free
Healthy plants resist pests best. Get the basics right:
Japanese Maple pests — FAQ
What is eating my japanese maple?
Japanese Maple (Acer palmatum) faces aphids as the most common pest, along with scale insects and gall mites. Aphids cluster on new growth causing curling and sooty mould. Scale feeds on bark and saps vigour. Deer may browse young plants. Healthy trees in good siting tolerate most attacks without lasting harm.
How do I get rid of aphids on japanese maple?
Tiny insects cluster on shoot tips and leaf undersides, causing curled, distorted, and sticky new growth; heavy infestations produce sooty mould on bark and leaves. Blast off with a strong jet of water — do not use horticultural oils on Japanese maples as leaf damage can result. Encourage natural predators (ladybirds, lacewings). Prune out heavily infested shoot tips.
How do I get rid of scale insects (japanese maple scale / horse chestnut scale) on japanese maple?
Oyster-shell-shaped or cottony crusts on bark and undersides of branches; sap-feeding reduces vigour, causing dieback and yellowing leaves in heavy infestations. Apply horticultural oil spray in late winter/early spring before buds break to smother overwintering scale. Time follow-up sprays to catch crawler stage. Remove dead wood.
How do I get rid of acer gall mites (aceria pseudoplatani) on japanese maple?
Microscopic mites cause small red or green pimple galls on upper leaf surfaces; alarming in appearance but rarely cause lasting damage to an established tree. No treatment normally needed — galls are cosmetic. Remove affected leaves if aesthetics matter. Ensure good tree vigour through watering and mulching.