Pine Sawyers

    Pine Sawyers

    Monochamus spp.

    pine sawyer

    Adult whitespotted pine sawyer borer (Whitney Cranshaw, Colorado State University, Bugwood.org)

    sawyer beetle larva

    Sawyer beetle larva (Milan Zubrik, Slovakian Forest Research Institute, Bugwood.org)

    sawyer wood galleries

    Black pine sawyer wood galleries (Milan Zubrik, Slovakian Forest Research Institute, Bugwood.org)

    Pest Description

    • adults: 5/8 – 1 inch; black beetles with whitish-gray markings, or not
    • very long antennae, about one to three times the body length
    • larvae: up to 1 inch long; white grubs without legs

    Host Plants, Diet & Damage

    • pine, fir, Douglas-fir, spruce
    • feed on the sapwood and heartwood of recently killed trees
    • trees are typically dead or near death when attacked

    Biology, Life Cycle & Damaging Life Stage

    • overwinter as larvae in the wood
    • feed on wood until mid-summer when they pupate
    • adults fly from July to September
    • eggs laid in chewed niches in the bark
    • one generation per year or every 2 years in northern climates
    • larvae are the damaging stage

    IPM Recommendations

    • Manage trees to improve or maintain overall health.
    • Primarily attacks recently killed trees; no control is recommended to protect trees.
    • Prune infested wood/branches and chip or burn.
    • No pesticide treatment is recommended.