Related Posts
French moth finds our trees très tasty
By DIANE VALDEN
COPAKE—What’s that crunching noise?
If it’s not your dog gnawing on a biscuit, it may well be a bunch of spongy moth caterpillars munching on your trees.
Cornell Cooperative Extension of Columbia and Greene Counties Community Horticulture Program Coordinator Sandra Linnell told The Columbia Paper last week the majority of calls she has received from residents this year have been about problems with spongy moth caterpillars. People say they hear the trees “crackling” with the chewing of these “very hungry caterpillars,” she said.
If you live in an area that has come under siege by these voracious critters, you know it. Normally leafy trees and even conifers have been stripped of foliage.
Ms. Linnell says areas up and down the Taconic State Parkway in Columbia County have been hard hit and are easily visible.
It’s been at least two months now since Karen LeRiche, who lives near Chrysler Pond in Copake woke up to find the trees and outbuildings around her house crawling with these hairy squiggling hordes.
“They love oaks,” Ms. LeRiche said in a phone interview, but they have eaten beech, birch and even pines on her four-acre property, she said.
After spending weeks combating the onslaught with her own two hands by picking them off and squishing them underfoot, Ms. LeRiche said the final straw came when the caterpillars headed for her beloved 100-year-old hemlocks. “That’s it, I’ve had it,” she said and hired a tree and lawn care specialist to spray and put an end to the infestation.
She wound up with a ton of dead caterpillars falling from the trees which she then raked into 15 piles or “berms,” mixed them with wood chips and made compost.
Now the adult moths have arrived and are mating and laying eggs.
Many may know the spongy moth (Lymantria dispar), by its former name, Gypsy moth, which the Entomological Society of America banished from its list in July 2021 because it is considered a derogatory term for the Romani people.
Spongy moths are not native to the U.S. but showed up from France (like the Coneheads?) in 1869. “Now widespread in the Northeast and considered ‘naturalized,’ they will always be a part of our ecosystem,” according to the state Department of Environmental Conservation (DEC) spongy moth fact sheet.
Spongy moth populations rise and fall in cycles, varying annually from few (most years) to gobs.
New York has regional outbreaks, or spikes in population numbers, every 10 to 15 years. Outbreaks usually end when disease and predator populations increase to a level at which they can naturally control the spongy moth population, says the DEC.
Ms. Linnell said it’s best to try to get a jump on the caterpillars in the early spring by wrapping a sticky tape or band around tree trunks so the caterpillars get caught before they can make their way up to the branches and eat the leaves.
The DEC recommends checking the sticky/barrier bands often, in case wildlife, such as birds and small mammals have been unintentionally caught; to remove debris that would act as a bridge for caterpillars over the band; and to replace as needed, such as after rain.
In mid-June, when caterpillars are larger, sticky/barrier bands can be replaced with a burlap trap. These traps do not prevent the caterpillars from going into the canopy but provide excellent shelter when they take a break from eating during the day, making it easier to collect and destroy the caterpillars, pupae, adults and eggs found in the burlap. The hairs on the caterpillars can cause skin irritation, so gloves are recommended when handling used traps.
The DEC also offers other options for dealing with spongy moths including:
•Microbial insecticides which are biopesticides made from naturally occurring bacteria, viruses, fungi, or protozoans that can target a specific pest
•Horticultural oil insecticides which are solutions refined from petroleum or plants, and when applied, can smother insects or disrupt the protective coating around their eggs
•Chemical insecticides, which are contact poisons that can have a serious impact on a variety of beneficial, native insects (such as bees), as well as nesting birds and other wildlife, so use should be limited.
The devouring of a tree’s leaves by spongy moth caterpillars does not necessarily kill the tree, but can cause stress. Ms. Linnell notes that the leaf eating when combined with “weird weather conditions,” such as a lack of rain, does pose a danger to trees. Without their leaves trees are unable to perform photosynthesis, the process by which light energy is captured and used to convert water, carbon dioxide, and minerals into oxygen and energy-rich organic compounds or food.
Ms. Linnell notes, without a source of food, a tree might not be strong enough to survive the winter.
The DEC says, “a healthy tree that has been fed on will grow new leaves and have a full canopy again within a few weeks. However, defoliation (loss of leaves) can reduce the health and vigor of a tree, causing it to become more susceptible to other stressors such as extreme drought, flooding, or attacks by disease or other insects. Tree death can occur when one or more of these stressors is present at the same time as spongy moth caterpillars. Long-term damage depends on the type of tree, as well as the amount of defoliation.”
To learn more about spongy moths including how to help trees recover from spongy moth damage, how to help predict next year’s caterpillar populations, and annual outbreak updates visit DEC’s spongy moth webpage:
