A Camden woman is encouraged that new technology tested in Rockland Dec. 15 was successful in removing browntail moth winter webs from the tops of trees.

A drone carries equipment designed by DeLeaves that removed browntail moth nests at the top of oak trees on the property of Guy Polyblank of Rockland. Photo by Anita Brosius-Scott

Anita Brosius-Scott has been following the work of DeLeaves, a Canadian company that invented equipment to snip samples from the tops of trees for the purpose of scientific study. She was thrilled to see a successful demonstration of the company’s innovative technology used for the first time to clip off branches infested with browntail moth caterpillar winter webs.

Brosius-Scott first heard about DeLeaves in March 2020, following the intense browntail moth infestation in the Rockport, Camden and Lincolnville area in 2019. At that time, there was talk in Camden about mechanical pruning of the moth’s winter webs, and a consensus among experts that both aerial spraying of pesticides and tree cutting are ineffective in stopping the spread of the destructive insect.

Through spring and early summer 2019 in Camden, browntail caterpillars stripped leaves from the tops of oak, apple and other trees, leaving behind poisonous hairs that cause an itchy and painful rash. There were sightings of hundreds of caterpillars crawling up trees, on vehicles and homes. The pests created a hazard in shaded yards and parks, on trails and at swimming areas. The rash sent people in droves to local pharmacies looking for relief.

In June, caterpillars form cocoons from which white moths emerge in July and August. The moths, attracted to exterior lighting at night, advance the infestation by flying from one area to another and laying their eggs on the underside of tree leaves. New caterpillars emerge, feeding on the tops of leaves. In the fall, colonies of caterpillars form winter webs on the tips of tree-top branches. Each January, Maine’s Forest Service counts these webs in an effort to predict the extent of the next infestation.

Brosius-Scott saw chemicals and tree cutting as “a terrible way to resolve this problem, yet the problem is literally physically unreachable.” When she heard DeLeaves had designed a branch cutting system transported to the tops of trees by an unmanned aerial vehicle, she thought this must be a solution.

She began corresponding with DeLeaves co-founder Guillaume Charron, and has continued to track the company’s work over the past two years. She felt certain the company’s technology could be applied to pest control, in keeping with her overarching priority “to benefit the earth, which is mother to us all, and the environment.” This same motivation has led her to work successfully with Camden’s Energy and Sustainability Committee, the Select Board and Town Manager Audra Caler on the solar installation at Sagamore Farm and replacement of conventional street lamps with energy-saving LED technology.

Since 2019, browntail moth infestation has receded in Camden, but continues to spread in Maine. A biological solution using fungus lethal to the caterpillars has a long development timeline, and requires damp spring conditions to work.

Charron was aware Camden did not see a major outbreak this year, but was willing to traveled to Maine for the company’s first trial use of their equipment for pest control, Brosius-Scott explained.

The team from DeLeaves travelled from Quebec, Canada, in a small hatchback sedan, with all the equipment they needed in a couple of suitcases, she said. They brought a small drone for filming controlled by one person and a much larger drone, with a larger controller, which carries the tree clipping mechanism. It is made up of a gripping mechanism that holds the branch to be sampled, a high definition camera with video transmission and a disc saw held in place by claw-like pincers for precision cutting.

She observed the mechanism remove browntail moth nests either one at a time, or by cutting off a larger branch with multiple nests. It took less than two minutes to remove a nest, and that could be improved with experience. After a nest is cut, it is dropped and retrieved for disposal by someone on the ground. The team saw the need for some possible adjustments to the equipment to deal with the smaller branches at the very top of trees, she said.

The company also invited arborist Eben Mann of Litchfield to observe the demonstration. Tom Massey, co-founder of Aerial Intelligence of Rockland was also at the demonstration. His company uses unmanned aerial vehicles for a wide range of services from 3-D mapping, to surveying, inspections, photography and video.

After the demonstration, Brosius-Scott continued her correspondence with Charron. “It is great to have a non-toxic option for removing browntail moth nests that are in particularly sensitive or important community locations,” she wrote. “We appreciated your empathy regarding the particular stresses that this insect places on people as well as trees, and our challenges regarding finding non-toxic solutions.”

Brosius-Scott sees biocontrol as the long-term solution to browntail moth infestation, and the DeLeaves machinery as an environmentally sound solution for individual landowners and specific places of high importance. Her interest is in “getting the knowledge and recognition out there that this solution exists.”

Photo by Anita Brosius-Scott

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