Waukesha County encourages residents to burn or bag and landfill their natural evergreen trees, wreaths, swags and other holiday decorations with foliage after highly invasive beetles were found on many items sold at large chain stores in Wisconsin this holiday season.
State tree inspectors found an insect called elongate hemlock scale, or EHS. EHS saps nutrients as it feeds on the underside of conifer needles, and threatens Wisconsin’s Christmas tree farms, native hemlock and balsam fir forests, and ornamental conifers in yards and parks.
“When it’s time to dispose of your live evergreen holiday decor, don’t put them on the compost pile or set the greens out for brush collection. Burn them if you can. If you can’t do that, bag them and send them to the landfill,” advised Brian Kuhn, director of the Plant Industry Bureau in the Wisconsin Department of Agriculture, Trade and Consumer Protection. “EHS has survived in the northeastern U.S., so winter weather will not kill it. As a result, if you compost this material, the insects may well attack conifers in your yard or neighborhood, and spread from there.”
EHS has a complex life cycle, going through several growth stages. After hatching from eggs, “crawlers” begin feeding on the underside of needles and secrete a cover around themselves as they grow, creating the “scale” that is visible. The crawlers may establish new infestations. Wind and birds may also disperse infestations to new trees.
EHS is very hard to control with pesticides, because it has overlapping generations with crawlers present all year long, and because the insects are protected by their hard, waxy coverings. EHS feeds on more than 40 conifer species, with hemlock, spruces and firs being among the most susceptible.
Residents should use their best judgement for disposal of evergreen trees. Non-infested trees can be collected by local municipalities for chipping or composting. Residents should check with their local municipality regarding burning regulations.
For more information about elongate hemlock scale, visit: https://datcp.wi.gov/Pages/Programs_Services/EHS.aspx