# Elm leaf beetle (Xanthogaleruca luteola) > A small yellow-green beetle that skeletonizes elm leaves, often causing repeated defoliation and overwintering in buildings and bark crevices. Source: https://insectscanner.com/species/elm-leaf-beetle/ (updated 2026-10-10) ## Is it dangerous? **Non-toxic.** Elm leaf beetles do not sting or transmit disease. They may be a nuisance when overwintering adults enter buildings, but they are not harmful. Remove or vacuum indoor beetles; no special first aid is needed for contact. **Pets:** Not toxic to pets. Large numbers on indoor surfaces may cause minor nuisance but do not pose a poisoning risk. ## Quick facts - Scientific name: Xanthogaleruca luteola - Also called: Elm beetle - Order: Coleoptera (Beetles) - Family: Chrysomelidae (Leaf beetles) - Size: 6-8 mm long - Colours: Yellow-green, Olive, Black - Habitat: Elm trees in urban, suburban and natural settings; adults overwinter in bark crevices, leaf litter and man-made structures - Range: Native to Europe; now established across North America and in parts of Asia and other temperate regions wherever elm trees grow - Active: Active spring through late summer; multiple generations possible in warm areas; adults most active during warm daylight hours - Lifespan: Adults live months, overwintering and reproducing the following spring; life span depends on season and climate - Effect on plants: Defoliator - Pest: yes ## Overview Xanthogaleruca luteola is a common defoliating beetle of elm trees native to Europe and now widespread in North America, parts of Asia and other regions. Adults and larvae feed on elm foliage; heavy or repeated infestations can weaken trees, reduce growth and cause aesthetic damage. Adults overwinter in sheltered places (including homes and buildings) and emerge in spring to lay eggs on elm leaves. Several generations may occur in a year in warm climates. ## How to identify it Adult beetles are small (about 6-8 mm), elongated and somewhat flattened, usually yellowish to olive-green with a black stripe along the outer edge of each elytron and small black spots on the head and pronotum. Larvae are slug-like, yellowish with two black stripes along the back and rows of black tubercles, and have a dark head. Eggs are yellow-orange and laid in clusters on the underside of elm leaves; bright orange-yellow pupae form off the leaf, often at the base of the trunk or in litter and crevices near the tree. - Adults 6-8 mm, yellow-green to olive with a black stripe along the outer edge of each wing cover - Larvae are soft, slug-like, yellowish with black stripes and rows of black bumps, feeding on the leaf underside - Look for egg clusters on the underside of elm leaves and characteristic skeletonized leaves from feeding - Overwintering adults often gather in cracks of bark or seek shelter in buildings in autumn ## Lookalikes - **Elm leaf miner** (Fenusa ulmi): Elm leaf miner creates narrow, pale leaf mines between leaf surfaces, while elm leaf beetle larvae feed externally and skeletonize leaves. - **Elm bark beetles** (Scolytus spp.): Elm bark beetles bore into wood and can vector Dutch elm disease; elm leaf beetle feeds on foliage and does not vector the disease. ## Life cycle - **Egg:** Laid in small clusters on the underside of elm leaves in spring and early summer; eggs hatch in about 1 week depending on temperature. - **Larva:** Slug-like larvae feed on leaf tissue, producing characteristic skeletonized leaves; larvae pass through several instars over 1-3 weeks. - **Pupa:** Larvae drop from the tree to pupate in litter, soil or crevices near the base of the tree for several days to weeks. - **Adult:** Adults feed on elm leaves, mate and lay eggs; late-season adults seek sheltered sites to overwinter and will sometimes enter buildings. ## Diet and predators - Young eat: Elm leaves (skeletonizing the leaf tissue) - Adults eat: Elm leaves; both larvae and adults feed on foliage - Predators of the young: Birds, predatory insects and parasitoid wasps (natural enemies reduce populations in some areas) - Predators of adults: Birds, predatory insects and some parasitic wasps; weather and predators help control populations ## Effect on plants and gardens Adults and larvae feed on elm (Ulmus) foliage, producing skeletonized leaves and, with repeated defoliation, reduced growth and vigor. Susceptibility varies among elm species; damage is mostly cosmetic but can stress young or repeatedly defoliated trees. ### How to get rid of it Practical control includes monitoring and removing egg clusters from the undersides of leaves, hosing off larvae, encouraging natural enemies (birds and predatory insects), using sticky trunk bands to trap larvae crawling down to pupate, and targeted insecticide treatments when damage is heavy. For large trees or severe infestations, consult an arborist about trunk injections or professional sprays timed to emerging adults and early larval stages. Seal entry points to keep overwintering adults out of homes. Use least-toxic options (neem oil, insecticidal soaps) where possible and follow label directions. ## Where and when to find it Check elm trees: eggs and larvae on the underside of leaves leaving skeletonized patches, orange pupae at the base of the trunk, and adults on leaves or resting in bark crevices and sheltered places in autumn. - Best time: Spring through late summer for feeding stages; autumn for overwintering adults. Daytime on warm sunny days is best for adult activity. - Tips: Photograph the underside of leaves to catch egg clusters, and take close-up shots of adults for identification. Wear gloves when removing large numbers from indoor areas. ## Fun facts - Adults often overwinter in buildings and can appear indoors in autumn as they seek shelter. - Larvae 'skeletonize' leaves by eating the soft tissue between veins, leaving a lace-like appearance, while adults chew small round holes. - Introduced to North America from Europe in the 19th century, it is a successful urban pest wherever elms are planted. ## Frequently asked questions ### Are elm leaf beetles dangerous to people? No. They do not bite or sting and are not harmful to people, though they can be a household nuisance when overwintering adults enter buildings. ### Do elm leaf beetles bite? No. Elm leaf beetles do not bite humans. ### Why are elm leaf beetles in my house? Adults seek sheltered, protected sites to overwinter and may enter gaps around windows, eaves or other openings in autumn. ### How do I get rid of elm leaf beetles on my trees? Remove eggs by hand, hose off larvae, encourage natural predators, apply sticky bands on trunks, or use targeted sprays early in the season. For severe outbreaks consult an arborist about professional treatments. ### Will elm leaf beetles kill my elm tree? A single year of feeding is usually cosmetic, but repeated heavy defoliation, especially on young or stressed trees, can weaken and in extreme cases contribute to decline. Good tree care reduces risk. --- More about this species: [iNaturalist](https://www.inaturalist.org/taxa/233683), [Wikipedia](https://en.wikipedia.org/wiki/Elm_leaf_beetle). Identify insects and spiders from a photo with the Insect Scanner iPhone app: https://apps.apple.com/app/id1543946563?pt=126685406&ct=web-markdown&mt=8 Identification from photos is never certain: don't handle insects you can't identify, and get medical advice for bites, stings or allergic reactions.