Pest identification
What's eating my american elm bonsai?
Elm leaf beetle (Xanthogaleruca luteola)
Signs: Skeletonized or window-paned leaf tissue; defoliation in severe attacks; larvae feed on leaf undersides
Control: Hand-pick larvae; apply pyrethrin-based spray; remove egg clusters from leaf undersides in early summer
Aphids
Signs: Curled leaves on new growth; sticky honeydew; colonies visible on shoot tips in spring
Control: Knock off with a strong water jet; spray with insecticidal soap; introduce or encourage natural predators
Spider mites
Signs: Fine webbing on foliage; bronze stippling across leaves; accelerated leaf drop in dry heat
Control: Increase humidity around the bonsai; apply neem oil or miticide; repeat every 5–7 days
Scale insects
Signs: Crusty bumps on bark; weakened branches; yellowing leaves as sap is drawn steadily
Control: Scrape off with a soft toothbrush; treat with horticultural oil during dormancy
Keep american elm bonsai pest-free
Healthy plants resist pests best. Get the basics right:
American Elm Bonsai pests — FAQ
What is eating my american elm bonsai?
American Elm Bonsai is most threatened by elm leaf beetles and spider mites in warm months. Aphids attack emerging spring growth, while scale can encrust older bark. Kept in outdoor conditions during the growing season, this bonsai can also attract caterpillars that skeletonize leaves rapidly if populations go unnoticed.
How do I get rid of elm leaf beetle (xanthogaleruca luteola) on american elm bonsai?
Skeletonized or window-paned leaf tissue; defoliation in severe attacks; larvae feed on leaf undersides Hand-pick larvae; apply pyrethrin-based spray; remove egg clusters from leaf undersides in early summer
How do I get rid of aphids on american elm bonsai?
Curled leaves on new growth; sticky honeydew; colonies visible on shoot tips in spring Knock off with a strong water jet; spray with insecticidal soap; introduce or encourage natural predators
How do I get rid of spider mites on american elm bonsai?
Fine webbing on foliage; bronze stippling across leaves; accelerated leaf drop in dry heat Increase humidity around the bonsai; apply neem oil or miticide; repeat every 5–7 days
How do I get rid of scale insects on american elm bonsai?
Crusty bumps on bark; weakened branches; yellowing leaves as sap is drawn steadily Scrape off with a soft toothbrush; treat with horticultural oil during dormancy