By Alicia Dziak
If you’ve been to Allegany State Park recently, you may have noticed masses of tiny caterpillars hanging from cabins, trees and other structures throughout the park. Unfortunately, these are not the caterpillars that will turn into beautiful butterflies come summer. Rather, they are gypsy moths, and they are becoming a problem at the park.
“The high population of gypsy moths was first discovered last summer by park staff who witnessed many moths flying around,” said Darrin Bierfeldt, a forester in the Allegany Region. “Shortly after, an employee of the U.S. Forest Service reported extremely high numbers of gypsy moth egg masses in the southeast section of the park.”
An estimated 9,000 acres of gypsy moth defoliation occurred last summer, creating stress to the affected trees. Additional defoliation to these trees, or trees previously stressed from other issues, could lead to tree mortality.
According to Bierfeldt, the gypsy moths are currently in their first to second larval stage, measuring around 3–6 millimeters with a black body color. After about eight weeks from emergence, they will have gone through five molting cycles and could measure up to two inches. At this time, their body will be covered with hair and will be dark colored with distinctive markings (five pairs of blue spots followed by six pairs of red spots) along the back. From there, they enter a brief pupal stage. Adult gypsy moths emerge from the pupae in 10–14 days. They are present from July into August.
Females have white to cream-colored wings, a tan body and a two-inch wingspan. Female gypsy moths cannot fly.
Males, which are smaller than females, with a 1.5-inch wingspan, are dark brown and have feathery antennae and can fly. Both the adult female and male can be identified by the inverted V-shape that points to a dot on the wings.
While most campers expect a few moths flying around their cabin porch light each night, being inundated with thousands of them while trying to eat a meal around the campfire is quite a different story.
How does the park plan to stop the spread of these moths?
“The Gypsy Moth Suppression program will treat approximately 2,052 acres in Allegany State Park,” explained Bierfeldt. “The treatment includes a single application of Gypchek to 1,050 acres of high use area. In addition, 1,002 acres of hemlock old growth forest will receive two applications of Gypchek.”
Gypchek is a viral insecticide, which only targets gypsy moth caterpillars. The active ingredient, nucleopolyhedrosis virus (NPV), naturally occurs wherever gypsy moths are present. NPV does not infect the caterpillars of other endangered species such as butterflies.
The scheduling of these treatments is dependent on weather, and larval and leaf development, but it is estimated that the first treatment will begin on May 16.
The treatment should not affect campers or visitors to the park, other than the brief noise of a low-flying plane.