The emerald ash borer, a tiny, invasive insect ravaging iconic ash trees across the Eastern U.S., has been detected in Monroe, according to state Urban Forest Coordinator Chris Donnelly and the Agricultural Department Experiment Station in New Haven.
Evidence of the insect has appeared on trees lining Highfield Drive and the tree stands to the north lining the ballfields at Masuk High School.
Monroe’s park ranger and tree warden, David Solek, confirmed the presence of the beetle and advised the Monroe Land Trust and Tree Conservancy, Monroe Green Committee and Monroe Conservation and Water Resources Commission.
The presence of emerald ash borers is marked by D-shaped holes in the bark of an ash tree no more than one-eighth-of-an-inch in diameter. Green ash with the peculiar-shaped punctures were sighted on Highfield Drive. In the Masuk area, a field survey revealed solitary digger wasps that prey on the ash borer were carrying larvae back to the wasp nests.
Whether an infected tree can be saved with chemical applications or other treatment depends on the maturity of the tree and how far the infestation has advanced, according to Clare Rutledge, associate agricultural scientist at the state experiment station.
Trees up to 20 inches diameter may be treated with systemic insecticides. For larger trees Rutledge recommends a consulting a licensed arborist.
The emerald ash borer is an invasive insect that measures less than a half-inch in length and is distinctive by its glossy, metallic-looking green wings and luminosity. Fieldwork by entomologists like Rutledge uncovered the insect’s presence in 24 communities across Connecticut in 2015, including Fairfield County communities of Westport, Wilton and Stratford.
The new discoveries mean the ash borer has now spread to as many as one-third of Connecticut’s 169 municipalities since its first appearance in the state in 2012. The incidence, driven by natural migration, continues to grow. Newtown was added to the list in 2013 and last year, Trumbull, Shelton and Bridgeport saw their first insects.
“A fair conclusion from what we know of the insect is that before we get too far down the road it will be found in every community in Connecticut, maybe not this year or even the next but fairly soon,” Donnelly said.
Since the insect’s arrival in the U.S. in 2002 — first reported in Michigan where packing crates originating in China were the suspected carrier — tens of millions of ash trees have been destroyed in 26 states, the District of Columbia and the Canadian provinces of Ontario and Quebec.
The infestation is the second scourge to level the ash stands of America. A blight called ash yellows swept across the U.S. some years earlier and killed countless numbers of trees, leaving others stressed and weakened.
Emerald ash borers attack only ash trees, no other species. The adult insects munch on the leaves, but it’s the larvae that are lethal. They feed on the cambium and phloem under the bark, technical terms for the interior layers that carry the nutrients vital to the life of the tree.
As a hardwood, ash has a quality of springiness and has been used for manufacturing furniture, baseball bats, tool handles, musical instruments and, at one time, hockey sticks and tennis rackets. It is also burned as firewood. But because of the ash borer there are restrictions now on exporting ash firewood outside Connecticut, also from other states.