June 22, 2021 Gypsy moths – what they mean for Lake George

Lake George’s forests aren’t looking so great right now, especially in Hague, Ticonderoga, and parts of the south basin, and many residents and guests have been quite concerned about the state of the trees on their land and surrounding mountains. The good news is, it’s NOT because of the invasive hemlock woolly adelgid (HWA), and though they look bad, these trees are not dead. The bad news is, it is because of another invasive pest, the gypsy moth.

Gypsy moths have been present in the United States since the late 1800s. In their caterpillar stage, this destructive critter feeds on the leaves of over 300 different plant species. Gypsy moth caterpillars especially enjoy eating oak leaves, but if there is a large enough infestation the caterpillars will eat just about any tree species that grows in our forests.

For some reason, 2021 has been an especially bad season for gypsy moths, and many, many trees have been defoliated. It is upsetting to see bare tree branches and to see these caterpillars on the ground, floating on top of the water, and hanging from trees.

It is important to note that generally, these infested trees are not dead. Most healthy trees can withstand a year of complete defoliation caused by gypsy moth caterpillars. We will have to wait to see what happens, but there is even a chance that these trees will grow their leaves back again this summer.

After talking with partners, the LGLC has learned that treating gypsy caterpillar infestations with chemical or biological means (using the naturally occurring bacteria Bt) would not be effective. Instead, here are some steps that you can take to improve the chance of survival of the trees on your property:

• this summer, especially if it is hot and dry, make sure that the trees on your property receive sufficient water. A tree that experiences stress from the gypsy moths will be less likely to survive a drought than an otherwise healthy tree free of infestation.
• in the fall, monitor your trees for gypsy moth egg masses. These egg masses are found on tree bark and can be scraped off of the bark and into a bucket of warm soapy water.
• early next spring, wrap tree bark with a barrier (for example burlap or a sticky band) that will prevent newly hatched gypsy moths from climbing up into the tree canopy and eating its leaves.

By July, the gypsy moths should fly away and (fingers crossed!) our trees will re-leaf.

Here are some links for more information:

See Page 4, Lake George Mirror (PDF download)
See Page 21, Glens Falls Chronicle (PDF download)

NYS Department of Environmental Conservation
Michigan State University Integrative Pest Management Program