Winter Moth Control

The Winter Moth starts as a caterpillar capable of defoliating entire canopies. Winter moths were first introduced into North America from Europe. It was first recorded in Nova Scotia in the 1930s and then in the Pacific Northwest in the 1970’s. Winter moth showed up in eastern Massachusetts in the early 2000’s and continued to spread throughout New England. The first record of Winter Moth defoliation in Maine was in 2012.

For effective treatment it is important to understand the life cycle of the Winter Moth. Adult winter moths emerge from the ground in November or December, but only the male is able to fly. The female climbs to the base of a tree or building and attracts the male through the pheromone that she exudes. 

After mating, the female lays a cluster of approximately 150 eggs under tree bark or in tree crevices, and her life is now over. In March or April the eggs hatch into a smooth green inchworm with a narrow white-stripe running lengthwise on each side of the body. The caterpillar spins a strand of silk, which, with the help of air currents, takes it into tree canopies in a dispersal method known as “ballooning.” Once there, the damage to the tree begins as the caterpillars work their way into the tree buds and leaves to feed. 

Winter moth caterpillars can also drop from trees to nearby ornamental shrubs such as roses. When feeding ends in mid-June the caterpillars migrate into the soil to pupate and emerge as moths.

Winter Moth Pest Control Treatments

The most heavily infested trees may be completely defoliated, and while healthy trees are capable of putting out a second set of leaves, the process puts severe stress on the tree. Research has shown that complete defoliation can reduce the annual growth rate of some oak species by as much as 47%, and successive defoliations can kill branches or entire trees. 

The impact of the caterpillars may also be exacerbated by secondary effects such as prolonged, cool springs, which allow the caterpillars to feed longer in the buds; dry years which put trees under additional stress; and infestations of other insects such as bark beetles, fungal parasites, or other moth species.

Here at Hawkes Tree Service we offer several chemical control methods that work exceptionally well against Winter moth caterpillars. Foliar sprays are applied directly to the surface of leaves using a high powered pump and tank system. When the caterpillars ingest the treated leaves, they will be fatally exposed to the product. We have several organic and synthetic products that we recommend for our clients.

Maine Pest Control Guidelines

The State of Maine has strict guidelines for which products and treatment methods may be used for Winter Moth within 250 feet of the mean high water mark. These laws are designed to protect the integrity of marine ecosystems and habitats. Inside this setback zone we recommend individual tree injections. Soil injections use a small volume of product inserted near the base of the tree’s root flares where the fibrous root hairs can absorb it. The systemic product is translocated throughout the tree with other nutrients and delivered to the new tissue in growing leaves. 

Trunk injections work in a similar way and use a systemic product as well. In this case, we actually drill a small hole into the root flares of the tree and insert a needle that is connected to a system containing our product. The tree will pull the product in as it does with water and other nutrients and when we are done the tree will compartmentalize the small wounds and quickly heal over.

Every property is a bit different when it comes to treatment methods for Winter Moth. If you would like more information or a free consultation for your property, please contact us or call today at (207) 442-7444.

You can also find more information about Winter Moth from the Maine Forest Service here and more information about policies from the Maine Board of Pesticide Control here.

Other Invasive Pests

In order to ensure the longevity of your trees and property, Hawkes Tree Service offers all kinds of invasive pest removal and mitigation services. Beyond the Winter Moth, we also offer treatments for invasive pests in Maine like the Brown-Tail Moth, Hemlock Woolly Adelgid, Emerald Ash Borer and Spongy Moth. Read more of each pest below, and click through to read more about each one!

brown tail moth caterpillars

Brown-Tail Moth

Browntail Moth is an invasive species that made its way the US from Europe in the late 1800’s. It quickly spread throughout New England where it became a nuisance for both trees and humans…
emerald ash borer on leaf

Emerald Ash Borer

The Emerald Ash Borer is an invasive species native to Asia. Despite its attractive lustrous color, it has the potential to eradicate Ash trees in the United States…
spongy moth on leaf

Spongy Moth

Formerly known as the Gypsy Moth, the Spongy Moth is native to Europe, and made their way to New England in the late 1860’s. They have voracious appetites and are capable of consuming a canopy…
close up of pine tree afflicted with Hemlock Woolly Adelgids

Hemlock Woolly Adelgid

HWA is a sap-sucking, scale-like insect that feeds on the needles of Hemlock trees and spreads very easily. It is found in most of coastal Maine and continues to spread, leaving many thinned…