Jessica Mathews / news@whmi.com


Every holiday season, millions of Christmas trees are cut and shipped around the country to become centerpieces for family celebrations and bring joy and tradition into homes. However, sometimes those trees carry more than just festive cheer but invasive pests that threaten forests and eco-systems.

The Michigan Department of Agriculture and Rural Development’s most recent webinar was “Holiday Hitchhikers: Unpacking Pests in Christmas Trees”.

Spongy moth and balsam woolly adelgid are two invasive Christmas tree pests on the Department’s “naughty list”. The webinar highlighted the status of these two insects in Michigan, their biology, the risks they pose, and how the department’s Christmas Tree Inspection and Certification Program helps Michigan tree farms spread holiday cheer without the risk of spreading invasive species.

Amber Neils is MDARD’s Quarantine Compliance & Export Specialist and said “Beyond the twinkle lights and tinsel, trees are a big deal for Michigan’s economy”.

Michigan is a top producer of Christmas trees – the 3rd in the nation – with 3 million trees supplied nationally every year. That translates to economic and cultural importance of between $30 to $40 million in sales annually which supports local growers, seasonal jobs, and rural communities.

Michigan also grows more than a dozen tree species for Christmas Trees, which also sets the state apart.

It was stated that it’s important to protect Christmas trees, traditions, and the livelihoods that come with them from invasive pests.

The Department’s role is to certify trees for export to open more markets, protect Michigan’s natural resources, help un-infested areas out-of-state stay that way; and instill trust in Michigan’s Christmas tree industry.

Key pests of concern for domestic export include the Spongy Moth (formerly known as the Gypsy Moth), Elongate Hemlock Scale, and European Pine Shoot Moth. Michigan invaders include Balsam Wooly Adelgid, Mountain Pine Beetle, and Southern Pine Beetle.

Any trees leaving the state need to be inspected and certified to ensure they’re free of spongy moth life stages and complex with the federal Spongy Moth quarantine.

The Spongy Moth was introduced to North America in the late 1860’s after being brought over from Europe and raised for possible silk production but escaped from enclosures. It’s currently found in 20 northeastern states.

Fun fact – Spongy Moths do not fly, have heavy wings, stay on a tree and send out a pheromone to attract the males. The caterpillars are said to be easy to spot due to bright blue and red markings.

Any grower that wants to ship trees out of state must enter into a compliance agreement with MDARD that outlines steps they’ll take to ensure trees are pest-free and what MDARD will also do.

Neils said whether a grower, buyer, regulator, or just someone who loves the outdoors; there are meaningful ways to help. She said one of the most impactful things someone can do is report unusual or suspicious pests – stressing early detection is one of their best tools in preventing the spread of invasive species. Neils added the state relies on the eyes and experience of people across the state to spot potential problems.

People are further encouraged to buy local whenever possible, as choosing Michigan-grown Christmas trees supports not only growers but reduces risk of introducing pests from other regions.

It’s also important to avoid moving plant materials long distances – especially things like Christmas trees and firewood as they can carry hidden pests that might not be visible at first glance and moving them can unintentionally introduce invasive species to new areas.

Neils said “Whether in the field, at a tree lot, or just enjoying the seasons; your actions can help protect Michigan’s forests and the future of our Christmas tree industry”.

A link to both the webinar and more information is provided.