No wonder it’s called the “gypsy” moth.

The non-native species was brought to Medford, Massachusetts in 1869, in hopes it could be used for silk production. The moths didn’t excel at silk production, but they did excel at reproduction and expansion. By 1932, they were found in Luzerne County.

Unfortunately, the critters seem to thrive in our area.

“Gypsy moths love the Pocono’s,” said Dr. Donald Eggen, who heads the gypsy moth spraying program for the state. Eggen’s doctorate is in the entomology of the gypsy moth and the forest tent caterpillar; he’s headed the PA spraying program for the past 15 years.

“Gypsy moths are here to stay, and our program is to protect the foliage on the trees.”

Last week, Department of Conservation and Natural Resources Secretary Cindy Adams Dunn announced Pennsylvania would begin aerial spraying of forestlands to combat gypsy moth populations poised for spring outbreaks in the northeastern and central portions of the Commonwealth. She said that sections of eight counties will be sprayed this spring in a suppression program covering 20,310 acres in Carbon, Lackawanna, Lehigh, Luzerne, Northampton, Schuylkill, Snyder, and Union counties.

Eggen explained that the goal of the suppression program is to prevent defoliation of the trees. The caterpillars go through five (males) or six (females) stages of growth, with the largest caterpillars doing the most damage.

“The gypsy moth caterpillars will feed on about 200 species, but they love oak,” he said. “They will eat the leaves about the time the leaves get to be full size – the tree has just used all its stored energy to put out the leaves, but now has to use energy reserves to put out more leaves.”

“When a tree is stressed, it opens the door for other things to attack,” he explained. “They can get root rot disease, or be attacked by a beetle that can actually smell out stressed trees.”

Most land being sprayed this year is state forestland. Private residential lands will be sprayed in Lehigh, Lackawanna, and Northampton counties, as they opted to participate in the cost-sharing program in 2018. Aerial spraying by helicopter and fixed-wing airplanes will be on state-managed forests and parklands, as well as residential county lands in three participating counties.

Eggen explained why spraying is very weather-dependent. The aircraft are outfitted with spray booms and carry a biological insecticide in a formulation to be sprayed at a rate of only ½ gallon per acre. Rotary atomizers disperse the spray in very tiny drops. GPS technology allows digitally-exact spray locations – in the past locations were marked with balloons.

“It (the droplet) has to be on a leave and the caterpillar has to eat it,” Eggen said. “If it’s very dry, the moisture evaporates out of it before it reaches the trees; wind, humidity and temperature are also factors.”

The population of the gypsy moths can also hit a downward trend if affected by either of two viruses, or a fungus. Each of these conditions are worsened by a big population of gypsy moths, which makes it more likely that the virus or fungus will spread.

“Think about what happens differently if you sneeze alone, or sneeze on a crowded subway,” Eggen said. “If it’s a cool and wet spring, that can increase the likelihood of the moths being affected by fungus spores.”

Though weather dependent, spraying is expected to be completed by the end of May or early June. Spraying progress and maps of the treatment areas will be posted on the DCNR Bureau of Forestry website, www.dcnr.pa.gov.