Gypsy Moth outbreak begins

Julie Sherwood
Trees like this in South Bristol have already been stripped bare by ravenous Gypsy Moth catepillars. Indicators are that a widespread outbreak, like that in the 1980s, has begun in the Finger Lakes region.

Leaf-eating caterpillars strip millions of trees of leaves with outbreaks in South Bristol and Middlesex

Early last month, the Gypsy Moth attacked the Bristol Mountain area of Ontario County. Now, the destruction from the leaf-eater is being seen across Central and Western New York. The state Department of Environmental Conservation reports this year’s “elevated populations” of the invasive insect “are causing noticeable defoliation” across the two regions.

The Gypsy Moths’ voracious appetite for leaves was seen first-hand by Bob and Kathy Taylor in South Bristol, as caterpillars stripped trees around their house and throughout their 32-acre property on Mosher Road.

In Yates County, Cornell Cooperative Extension Natural Resource specialist Laura Bailey says the outbreak began last year. Now Vine Valley in the town of Middlesex has been hardest hit, and CCE have received other reports all over the county.

In South Bristol, Bob Taylor had to use a pressure washer to remove the thick carpet of caterpillar droppings covering the porches and deck. The caterpillars recently advanced to the cocoon stage, blanketing his home’s outside walls, around windows and flower boxes.

On Stid Hill Road in South Bristol, Victor and Kate Logan also watched as Gypsy Moths ate the leaves off their trees. The caterpillars recently morphed into the cocoon stage and some began emerging as moths.

Experts say most trees can survive the damage from Gypsy Moths alone. But what Gypsy Moths do can leave trees vulnerable to other invasive species that kill. Those include the hemlock woolly adelgid, which attacks North American hemlocks, and the emerald ash borer, an invasive beetle that kills North American ash species.

Russell Welser Sr., resource educator for Cornell Cooperative Extension of Ontario County, has fielded many questions from people asking what they can do about the gypsy moths.

There are chemical treatments but the period when those may have been effective has passed for this season. “Hardwood trees (oaks, maples, hickories, etc.) may be able to survive two or more years of defoliation, if they are in good health to begin with,” Welser said. “Evergreens, on the other hand, are likely to die after one year of defoliation.”

Rob Williams is an invasive species program manager in New York for The Nature Conservancy. He said it’s good to know which types of trees are vulnerable to invasive species in order to avoid planting them in the first place. Planting and promoting trees that can thrive builds resilient forests, he said.

The Gypsy Moths will continue to emerge from cocoons in July and August. Mating and egg laying occurs during this same time. Each egg mass contains several hundred eggs. These eggs overwinter and hatch the following spring, starting the cycle over again.

Welser said the Gypsy Moths may be in high numbers for two or three years depending on food availability and disease pressure. Welser said there’s a good chance next year may be similar to this year.

Here’s a little history from the DEC: “Gypsy moths were accidentally introduced in 1869 when they were brought to the U.S. in the hope that they could breed with silkworms to create a hardier variety of silkworm and develop a silk industry in the U.S. Even though they failed as a textile producer, some of the gypsy moths escaped and established their first U.S. population in Medford, Massachusetts.”

Bailey says Gypsy Moths are an outbreak species, with major defoliation events happening every 10 to 20 years, depending on the weather, and generally spread, lasting a few years.

In the 1980s, a major outbreak lasted several years in the Northeast, and saw major forested areas like Keuka Lake’s Bluff virtually bare of leaves by late summer.

Includes reporting by John Christensen.