Keep a close eye on your trees and shrubbery.

Gypsy moths are making a comeback, and the little caterpillars are bringing along their big appetites.

Carbon County commissioners have voted to submit a letter of intent to participate in the 2015 Gypsy Moth Suppression Program through the Pennsylvania Department of Conservation and Natural Resources, Bureau of Forestry, Division of Forest Pest Management.

Commissioners Chairman Wayne Nothstein said this is the first time since 2009 that the county has opted into the program.

"We haven't had an issue lately," he said. "But we are having a little bit of a problem right now."

Nothstein said the county may or may not need to use the program, pending on what data is collected, but the county wanted to opt in in case it is needed.

Nothstein said that the area around Mauch Chunk Lake Park has seen an increase in the concentration of gypsy moths.

The pest

The gypsy moth, or Lymantria dispar, has been a pest to the northeastern United States since being introduced from Europe to Massachusetts in 1869, DCNR reports.

The bug was first discovered in Pennsylvania in 1932, when it was found living in Luzerne and Lackawanna counties.

It is typically known to homeowners in its larval stage as a caterpillar.

During the bug's life cycle, a female lays 400 to 600 eggs, which hatch in late April.

The caterpillars then feed on foliage as they mature.

By late June or early July, gypsy moth caterpillars burrow into tree trunks and create pupas, where they will remain for about two weeks. They will then emerge as adults by late July.

After decades of dealing with the pests, DCNR's Bureau of Forestry created the suppression program in 1968, which has helped cut down on the amount of damage caused by these insects.

The program

According to DCNR, the Gypsy Moth Suppression Program's goal is to "prevent gypsy moth-caused defoliation in treated forest residential area from exceeding 30 percent on 80 percent or more of the highly favored host trees."

To qualify for the program, the forested area must contain trees 25 feet or more in height and have at least 50 percent of the surface area covered by the crowns of the trees.

Of that total, 20 percent or more of the crown must be comprised of highly favored species, including apple, aspen, basswood, beech, birches, box elder, hawthorn, larch, oaks, willows and witch hazel trees.

The property must also contain at least 250 healthy, current-season gypsy moth egg masses per acre to qualify for the program.

Egg masses can be located under rocks and in trees.

The results

Once an area is determined to be infested, insecticide is sprayed throughout the area to kill the larvae. The insecticide will not eradicate the problem though, because of "limitations of the insecticides available and the establishment of the gypsy moth in Pennsylvania, it is not economically feasible or biologically possible," according to DCNR.

Nothstein said that the county is taking this step as a precaution in case it is determined this year that the area needs to be sprayed.

"We could possibly use it this year pending on how bad the gypsy moths get," he said.

A total cost to spray the county if necessary has not been determined and would be based on per acre sprayed.