They're back! Remember the Gypsy Moth?

There is clear evidence that the gypsy moth has returned to our area in large numbers.

Anything above 250 egg masses per acre of forest is cause for concern, and ranger David Horvath at Mauch Chunk Lake Park is reporting 1,700 masses per acre at the campground and picnic areas of the lake. He expects similar results on the south side of the lake.

The state offered a co-pay grant to fund a limited campaign of aerial spraying for properties or blocks of properties with at least 23 acres of forest and an egg mass count of at least 250 masses per acre. The deadline for application was Aug. 30. Any area proposed for treatment must also obtain final approval from the Pest Management Division of the Bureau of Forestry.

Carbon County plans to use a biological control known as Bt (Bacillus thuringiensis), a naturally occurring soil bacteria that produces a toxin harmful to some insects, including the gypsy moth.

They will spray Bt on the south side of Mauch Chunk Lake, and on the north side from the boat launch through the campground. The program to spray Bt has limited funding, and Horvath has already contacted landowners who qualify.

For the rest of us who want to protect our trees, there is a free, online guide called "Homeowners Guide to Gypsy Moth Management," which is available at www.nj.gov/agriculture/divisions/pi/pdf/GMguide.pdf. Copies and more information are also available from Master Gardeners at the Penn State Extension office, 529 Lentz Trail, Jim Thorpe, PA 18229, or by calling 570-325-2788.

What to do this fall

The best protection against this pestilence is to scout out egg masses, remove them with a gloved hand, and then bag and burn them.

You'll find moth eggs on tree bark, buildings and building foundations, stones, woodpiles, tools, play equipment, and anything stored outside. Finding them can be a family project because the more eggs you remove this fall, the fewer larvae will be on your trees in the spring.

Hatching is timed to the emergence of the leaves the larvae need for food. To survive, they need to feed from certain host trees for the first three molting cycles (instars). After that they are able to digest a wide variety of tree foliage including pine, spruce and hemlock. Detailed information about susceptible trees is given in the homeowner's guide.

This fall, take an inventory of the susceptible trees on your land so you are ready to help those trees survive gypsy moth invasion. Also identify susceptible trees within 600 feet from the center of your property. This may mean cooperating with your neighbors to protect those trees.

What to do in the spring

When the larvae hatch, some will be forced to migrate along the ground to locate a susceptible tree. Once there, they will climb up the trunk into the canopy and begin to defoliate the tree.

This is the second place a homeowner can intervene. If you have taken an inventory of your susceptible trees in the fall, early April is the time to put sticky bands around the trunks of those trees. The sticky bands are available from garden centers.

Sticky bands do not stop the caterpillars that are already up in the canopy. These defoliators can travel in the air by means of silk threads they dangle into the wind. A considerable number of them fail and fall to the ground, but many land in a host tree and continue their path of destruction.

What else can be done

If your infestation is small, under 250 egg masses per acre, you may be able to tolerate the damage. The formula is: 250 masses per acre would result in noticeable defoliation. At 500 masses per acre, the defoliation would be very noticeable. And at 1,000 masses per acre, there would be massive defoliation.

If you need chemical controls it is best to hire a professional tree company that is licensed to apply pesticides. These chemicals can kill other butterflies and moths as well as the gypsy moth larvae. Also, there is always drift during aerial spraying and it is best to let your neighbors know you plan to spray. Pesticides won't eliminate the gypsy moth nor will they shorten the infestation period. They will reduce its numbers, however, and that can be crucial if a valuable tree is under attack.

Gypsy moths have natural enemies. They are susceptible to a virus, a parasitic fungus and a parasitic wasp. The conditions in the environment also make a difference as to the size of the coming generation. A devastating infestation in this cycle may not be repeated for several years due to these factors.

With gypsy moths sure to be a problem in 2015, act now to save your trees. Download the homeowner's guide. Read the instructions and set up an action plan to control the infestation. Protect your vulnerable trees now by removing egg masses from your property.

Now and in the spring, Carbon County Master Gardeners are available Tuesday mornings at the Penn State Extension office in Jim Thorpe.

The following contributed to this article:

• David Horvath, park director, Mauch Chunk Lake Park, Jim Thorpe

• Jeff Wartluft, former ranger and now forest consultant, Lehighton

• West Virginia University Extension: Homeowner's Guide to Gypsy Moth Management