Elm Leaf Beetle

    Elm Leaf Beetle

    Xanthogaleruca luteola

    elm leaf beetle

    Elm leaf beetle (Joseph Berger, Bugwood.org)

    elm leaf beetle larvae

    Elm leaf beetle larvae (Pest and Diseases Image Library, Bugwood.org)

    elm leaf beetle damage

    Elm leaf beetle damage to leaves (Whitney Cranshaw, Colorado State University, Bugwood.org)

    Pest Description

    • adults: ~ 1/4 inch; yellowish green; black stripes on wings
    • larvae: initially black; become yellowish after feeding
    • older larvae: ~1/3 inch; rows of black projections on their backs that resemble stripes
    • eggs: yellow; laid in double or triple rows of up to 25 on the undersides of leaves

    Host Plants, Diet & Damage

    • elm and zelkova
    • larvae skeletonize and adults chew holes in leaves
    • damaged leaves turn brown and may drop prematurely
    • trees may die after multiple years of repeated defoliations
    • adults can become an overwintering structural nuisance

    Biology, Life Cycle & Damaging Life Stage

    • overwinter as adults on or near host trees
    • adults emerge in spring when new leaf growth starts
    • eggs are laid on the undersides of leaves
    • larvae feed in groups on undersides of leaves
    • larvae pupate on the ground or in bark fissures
    • new adults emerge in about 2 weeks and lay eggs
    • two generations per year are common
    • larvae are the primary damaging life stage; adults also cause damage

    IPM Recommendations

    • Manage trees to improve or maintain overall health.
    • Pesticides are not typically needed.
    • Monitor the undersides of leaves for eggs and larvae or take note of previous year’s populations and damage.
    • Consider foliar sprays (azadirachtin; carbamate; pyrethroid; spinosyn) for newly hatched larvae.
    • Apply a soil (imidacloprid; dinotefuran) or foliar systemic (acephate) after leaf expansion.
    • Apply an insecticidal bark band (carbamate; pyrethroid) a few feet wide to intercept 1st generation larvae.