2017-09-15 / Community

Cape officials warn of damage-causing moth

By Michael Kelley
Staff Writer


New Cape Elizabeth Tree Warden Todd Robbins is hoping to develop a plan to manage the winter moth population over the next few months for both municipal trees and trees on private property. In high numbers, the moth strips trees of their leaves leaving them vulnerable. (Courtesy photo) New Cape Elizabeth Tree Warden Todd Robbins is hoping to develop a plan to manage the winter moth population over the next few months for both municipal trees and trees on private property. In high numbers, the moth strips trees of their leaves leaving them vulnerable. (Courtesy photo) CAPE ELIZABETH – Winter month, an invasive moth first introduced into North America from Europe in the 1970s and seen in the New England area for the last 15 years, has come to Cape Elizabeth, stripping many trees of their greenery, leaving them vulnerable.

Tree Warden Todd Robbins said the epidemic is growing and he will put a plan in place this winter to curb damage the moth causes not only throughout town, but the area as well.

“It has become quite (prevalent) from Scarborough all the way to South Portland,” Robbins said.

The spread of the month is compounded by landscape materials, such as leaves or grass clippings and vehicles or boats being moved from one area to another.

Robbins said from November through January male and female moths, are active during above freezing temperatures. The eggs, which the female lays in the bark, hatch in spring. Between April and June, the larvae eat the leaves of many trees found throughout Cape Elizabeth, stripping the tree of its leaves in many cases. Between June and November, the larvae pupate in the soil before coming out in the winter as mature moths.

“If all the winter moth did was tatter the leaves, we wouldn’t have a problem,” Robbins said in a presentation of his plan to councilors on Monday, Sept. 11. “What causes a problem is when there is a high concentration of winter moth, they completely strip the leaves off the tree and the tree forces out a second set of leaves in a given year. When this happens three to four years in a row, the tree has used up all of its reserves and it will die.”

The moths are typically found on varieties of fruit trees, as well as oak, maple, ash and elm trees. Robbins said since 40 percent of Cape Elizabeth’s trees are oak, the town’s tree population is at risk.

“If we lost all of our oaks to disease or species, how would our town look? It’d look bare,” he told councilors.

This winter, Robbins will monitor moth activity, remove dead trees in the town right of way and work with private landowners who have trees on their property that are affected and “pose a risk to public roads, structures or areas of activity” and implement integrated pest management techniques to control the moths’ impact.

Robbins will replace the trees he takes out with native tree species that are not hospitable for winter moth activity, which include hickory, American linden, American beech, American sycamore, Kentucky coffeewood, tulip poplar, sweetgum, black walnut, northern catalpa and black gum trees. Robbins recommends property owners use those species of trees as well.

Town Manager Matthew Sturgis said a list of preferred street trees is noted in the town’s subdivision ordinance. Public Works Director Bob Malley said the list has recently been updated.

Property owners who want to protect their trees can also use a series of integrated pest management solutions that, Robbins said doesn’t wipe the species out, but manages it. Solutions include banding the tree with sticky strips, available at sheltertree.com, that catch the female moths or using landscape horticulture oil (available at hardware stores) to kill the eggs or hiring a landscape professional to apply a spray or systemic injections. There are pros and cons with each technique, Robbins said. The spray, for example, kills the moths, but can get other places, while the injection is expensive, but lasts multiple seasons and the oil doesn’t get the majority of the eggs laid.

“I have no preference to one or another. You are just trying to manage (the species with these techniques). I think all of them do that,” said Robbins, who took over as tree warden from Mike Duddy this spring.

Another alternative that could keep the winter moth population under control is releasing cyzenis albicans, a species of fly that preys exclusively on winter moth. Two releases were done at Two Lights State Park, where winter moth issues first appeared, but Robbins said “there may have the be additional releases considering the epidemic is so widespread.” The fly, however, is difficult to breed and competition to obtain them is high.

While the moths can be found all over town and are particularly prevalent by Two Lights State Park and Crescent Beach State Park, Robbins said moth activity has recently been noted in Fort Williams Park, but the trees impacted there are “relatively safe.”

“The infestation is there. Some level of integrated pest management needs to be levied there, but next year you’re not going to see dead oaks because of winter moth and in my opinion in the next couple of years you aren’t going to have dead trees as a result,” Robbins said.

For more information or questions, contact Robbins at 756-4113 or todd.robbins@blackpointcorporation.com.

Staff Writer Michael Kelley can be reached at 282-4337, ext. 237.

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