Fingergall and Pouchgall Mites

    Fingergall and Pouchgall Mites

    Eriophyes negundi; Phytoptus emarginata

    boxelder pouchgall mite galls

    Galls on leaves produced by boxelder pouchgall mites (Whitney Cranshaw, Colorado State University, Bugwood.org)

    linden gall mites

    Linden gall mite (Milan Zubrik, Slovakian Forest Research Institute, Bugwood.org)

    willow leafgall mite

    Willow leaf gall mite (Whitney Cranshaw, Colorado State University, Bugwood.org)

    Pest Description

    • minute, four-legged, cigar-shaped mite; opaque white to yellow in color
    • microscope or hand lens required to see mites; use symptoms for identification
    • there are many finger and pouchgall mites that affect other plants/trees

    Host Plants, Diet & Damage

    Boxelder Pouchgall Mite

    • boxelder leaves
    • galls are raised green domes on the top of the leaf

    Chokecherry Fingergall Mite

    • chokecherry and other Prunus spp. leaves
    • fingerlike galls scattered randomly on leaf surfaces; turn yellowish to light brown

    Biology, Life Cycle & Damaging Life Stage

    • overwinter in budscales
    • emerge from budscales in spring just prior to budbreak
    • migrate from buds to feed on new leaves in spring
    • migrate back to buds in the fall
    • immatures and adults are damaging

    IPM Recommendations

    • Damage is aesthetic; tolerate pest.
    • Apply horticultural oils at budbreak to target migrating mites.
    • Apply an insecticide (avermectin; carbamate; METI acaracide; insecticidal soap; lime sulfur; tetronic and tetramic acid derivatives) at or just prior to budbreak.
    • Do not use horticultural oils in combination with, or within 30 days of applying sulfur or a sulfur-containing product.

    For more information, see our Eriophyid Mites fact sheet.