How to prevent nasty bugs from roaming around on Christmas decorations

Nobody enjoys uninvited guests disrupting holiday celebrations.

It’s annoying enough when it comes to distant friends or relatives. But when it comes to what’s lurking in your holiday decorations, it can be a disaster for home ecosystems.

For this reason, the Maine Department of Agriculture, Conservation and Forestry is advising Christmas tree growers and wreath makers of the importance of preventing the spread of pests in and out of Maine on Christmas decorations containing plant material.

“Invasive insects, diseases and plants can easily be transported long distances on Christmas trees and wreaths,” said Gary Fish, state horticulturist with Maine DACF. “All of these pests can originate on old wreaths or trees left in the yard after the holidays.”

Boxwood branches and leaves are a popular wreath material, especially for people who want the decorations to last beyond the holidays. According to Maine DACF, this year it is more important than ever to know the origin of boxwood greenery because it could contain boxwood borers.

The moth is a new invasive species that was first discovered in New York two years ago. It is difficult to detect and the caterpillars can kill the plant by quickly stripping off its leaves and girdling its stems.

In Maine, hardy boxwoods are popular landscape plants, including in hedges.

Boxwood borers overwinter as small caterpillars in a structure called a hibernaculum, which consists of a few leaves connected together by a web. In this structure, caterpillars can easily hide and survive in any boxwood material, including live or cut plants and stems used in Christmas decorations.

To keep the moths out of Maine, DACF wants you to stay away from all sources of boxwood in Niagara and Orleans counties, New York. Clinton, Eaton, Ingham, Jackson, Lenawee, Livingston, Monroe, Oakland, Washtenaw and Wayne counties in Michigan; Hamilton and Clermont counties in Ohio; and all of Massachusetts.

If you’re thinking about sending Christmas decorations made in Maine using fresh plant or tree material, keep in mind that there are pests here that aren’t found in other states.

“All states, through the National Plant Board and USDA-APHIS (Animal Plant Health Inspection Service), are working together to prevent or slow the spread of invasive species that threaten plant health in all states, tribal lands or territories,” Fish said. “We comply with quarantines implemented by each state.”

So before you ship anything with live Maine vegetation, check it first for insect activity and whether you’re even allowed to ship it to its intended destination.

There is also a USDA federal quarantine for the gypsy moth – formerly known as the gypsy moth – active in Maine.

This means USDA certification is required to bring plant materials sourced in Maine – including live trees, felled trees, wreaths or cut branches grown outside of a greenhouse – to any state other than Delaware, Maryland, Massachusetts, Michigan, New York , Pennsylvania, Rhode Island or Vermont because they are already infested with the moth.

Certification is available from the USDA Plant Protection and Quarantine Office in Maine.

Gypsy moth caterpillars are invasive pests on many hardwood species in Maine, including oak, apple, birch, poplar and willow. The caterpillar can destroy large areas of trees by defoliating them.

The moth overwinters as eggs, which are deposited on trees and other outdoor surfaces in yellow-brown masses that resemble sponges. This allows them to easily spread to other areas when egg-infested greenery is used to create holiday decorations.

A small but serious pest with piercing and sucking mouthparts has become established along the southern coast of Maine from York to Hancock Counties.

The elongated hemlock scale beetle uses these mouthparts to drink the fluid from the needles of hemlock, pine, fir, spruce, cedar, yew and juniper trees. This causes the needles to die and fall off.

Wisconsin now has a quarantine preventing oblong hemlock from entering the state. To ship Christmas decorations made from affected trees in Maine, you must contact state horticulture program officials at [email protected] for possible export certification.

Searching for invasive attacks is something that should be practiced year-round, Fish said.

“I think the holidays are important, but less important than international trade or transportation of firewood,” Fish said.