Poplar and Willow Borer

    Poplar and Willow Borer Weevil

    Cryptorhynchus lapathi

    poplar and willow borer

    Poplar and willow borer weevil (Gyorgy Csoka, Hungary Forest Research Institute, Bugwood.org)

    poplar and willow borer larva

    Poplar and willow borer larva (Fabio Stergulc, University of Udine, Bugwood.org)

    poplar and willow borer damage

    Poplar and willow borer damage (Milan Zubrik, Forest Research Institute - Slovakia, Bugwood.org)

    Pest Description

    • adults: ~ 5/16 – 3/8 inch; long snout; black with white/brown markings; resemble bird feces
    • larvae: up to 5/16 inch long; white grubs without legs; brown head capsule

    Host Plants, Diet & Damage

    • primarily willow; poplar
    • young/newly planted trees preferred
    • damage typically occurs on the lower stem
    • adults cause minor chewing injury on stems and shoots
    • larvae feed on inner bark into the sapwood
    • frass is pushed out from the entrance holes
    • cause deformation and weakness of branches and stems
    • smaller diameter trees can be killed

    Biology, Life Cycle & Damaging Life Stage

    • overwinter as larvae in the sapwood
    • larvae resume feeding in the spring
    • pupate under the bark around May
    • adults present from May to mid-July
    • one generation per year
    • larvae are the primary damaging stage

    IPM Recommendations

    • Manage trees to improve or maintain overall health.
    • Remove and destroy infested plant material.
    • Apply an insecticide (carbamate; pyrethroid) to the main stem May through mid-July.