Learn / Ask The Landscape Professional
I have these moths all over my house. What in the world are they? Help! Gerald
Gerald, what you are seeing is called a
Winter Moth, Operophtera brumata. These moths are an invasive
insect pest prevalent throughout Europe that first showed up in
Nova Scotia after World War II. Since then, they have emerged in
western Canada, Oregon and the state of Washington. Over the
last ten to fifteen years, parts of eastern New England have become
infested with them. The hardest hit areas are Massachusetts east of
Route 495, especially Cape Cod and Martha's Vineyard. They have
also been observed in Rhode Island, southeastern New Hampshire,
Maine and steadily moving into Southeastern Connecticut.
The moth, which is the adult stage of the Winter Moth, first
shows up around Thanksgiving and will
be seen into January if the temperatures remain above freezing.
The male Winter Moth will often be
seen in large numbers flying around outside lights.
The female Winter Moth has stubby wings and
cannot fly. Once the eggs are laid, both male and
female moths die but the eggs survive the winter.
Each female lays ~150 eggs, often in the bark
of trees. In April, when the temperature averages
around 55 degrees, the eggs hatch into caterpillars
that eventually grow to about an inch long. The
caterpillars can show up in incredible numbers.
The caterpillars feed on buds of leaves and flowers
as well as on developed leaves of apple trees,
crabapples, beech, cherries, blueberries, oaks,
maples and a wide range of other trees and plants.
After several years of complete defoliation, trees
are seriously stressed to the point they can eventually die.
Help is already on the way in the form of a small fly called
Cyzenis albicans, which has shown to be an effective
biological control of Winter Moths in Nova Scotia and British
Columbia. This fly is a parasite that infests the Winter Moth by
laying its eggs on leaves eaten by the Winter Moth caterpillars
and the fly eggs hatch inside the caterpillar. This fly is a
specific control for the Winter Moths; when the Winter Moth
disappears, so does the Cyzenis albicans fly. This control
method is being led locally by UMASS Amherst. It is expected
within a decade the Winter Moth will be no more of a nuisance
than the Gypsy Moth.
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About Linda Lillie
Linda K. Lillie is the President of Sprigs & Twigs, Inc, the premier
landscape design and maintenance, tree care, lawn care, stonework, and carpentry
service provider in southeastern Connecticut since 1997. She is a graduate of
Connecticut College in Botany, a Connecticut Master Gardener and a national
award winning landscape designer for her landscape design and landscape installation work.