Gypsy Moth: Atlanta Diagnosis & Treatment Guide

What Is Spongy Moth (Formerly Gypsy Moth)?

Spongy moth (Lymantria dispar, officially renamed from gypsy moth in 2022) is an invasive insect whose caterpillars feed heavily on the leaves of hardwood trees. The pest is not currently established in Georgia, but state and federal agencies trap for it every year because a single accidental introduction, often on outdoor furniture, vehicles, or firewood moved from infested states, could start a local outbreak.

How to Recognize It

• Chewed leaves with small holes early in the season, progressing to leaves eaten from the outer edge toward the center.
• Heavy leaf loss (defoliation) on oaks and other hardwoods in late spring and early summer.
• Hairy caterpillars up to 2.5 inches long with five pairs of blue dots and six pairs of red dots along the back.
• Buff or tan colored egg masses about the size of a dime to a quarter, often tucked under bark, eaves, lawn furniture, or wheel wells.
• Caterpillar droppings (frass) raining down from the canopy onto decks, driveways, and patios.
• Stripped or thinning canopies on otherwise healthy trees by June.

In Georgia's climate, eggs would hatch in late March, and caterpillars feed and cause most of their damage from April through May. Pupation happens in late May or June, with adult moths emerging 10 to 14 days later, so damage is concentrated in spring and very early summer.

Why It Matters for Atlanta Trees

A single year of defoliation rarely kills a healthy tree, but repeated defoliation, or defoliation combined with drought, root damage, or other stress, can weaken trees enough to kill them or leave them open to secondary borers and fungal diseases. Because spongy moth is not yet established in Georgia, early detection of any suspected egg masses or caterpillars matters, both to protect the individual property and to help state agencies prevent a wider outbreak. Atlanta's tree canopy includes many preferred hosts, especially oaks (white oak, red oak, water oak), along with crabapple, willow, hawthorn, birch, linden, and hickory, all of which would be vulnerable if the pest arrived.

General Prevention

• Do not move firewood from other states into Georgia, even for camping, since egg masses ride on bark.
• Inspect outdoor furniture, grills, RVs, trailers, and boats that have been stored or used in northern or mid-Atlantic states, and scrape off any tan, fuzzy egg masses you find.
• Keep trees vigorous with deep, infrequent watering during drought and a proper layer of mulch (not piled against the trunk), so a defoliated tree has the reserves to push a second flush of leaves.
• Report suspected egg masses, distinctive blue-and-red-dotted caterpillars, or unusual oak defoliation to the Georgia Forestry Commission so traps can be set.

What NOT to Do

• Do not self-diagnose. Many tree problems look alike, and treating the wrong one wastes time and can harm the tree.
• Do not apply fungicides, insecticides, or other chemicals without an arborist's specific recommendation. Wrong product or wrong timing makes things worse.
• Do not crush, burn, or otherwise destroy a suspected egg mass before it has been documented. If you believe you have found spongy moth, photograph it in place and contact the Georgia Forestry Commission or a certified arborist first, since confirmed reports help state surveys.

Related Services

For most diagnosis and treatment questions, the right starting point is one of our services:

• ISA-Certified Arborist Services for diagnosis, consultation, second opinion.
• Plant Health Care (PHC) for ongoing tree health management.
• TRAQ Tree Risk Assessment for when the tree may be a safety hazard.

Sources

This page summarizes general information from: Georgia Forestry Commission, Clemson Cooperative Extension HGIC, The Morton Arboretum, and USDA Forest Service (Forest Insect & Disease Leaflet 162).