Georgia's warm, humid climate is great for growing trees, and it's just as good for growing the insects that feed on them. From the pine beetles that flare up during droughts to the borers killing our ash trees, recognizing the warning signs early is the difference between a treatable problem and a removal. As family-owned, ISA Certified Arborists with 15-plus years working on metro Atlanta trees, we deal with these tree pests in Georgia every week. Here's what attacks what, how to spot it, and when it's time to act.
Bark Beetles: Southern Pine Beetle and Ips Engravers
Pines dominate the metro Atlanta canopy, which makes bark beetles our single biggest pest concern. The southern pine beetle (Dendroctonus frontalis) and the three common Ips engraver beetles attack loblolly, shortleaf, and other Southern pines. The classic warning sign is pitch tubes, popcorn-sized blobs of hardened resin on the bark where the tree tried to push the beetle out. You may also see fine reddish boring dust in the bark crevices and S-shaped galleries underneath.
Drought matters. Metro-Atlanta pines are especially vulnerable to bark beetles when they're stressed by drought, construction damage, root compaction, or lightning. Healthy, well-watered pines can pitch out small attacks; stressed ones can't. Once the crown fades from green to red, the tree is already dead and the beetles have usually moved on to the next pine.
Management is mostly about prevention: keep pines watered during dry spells, avoid soil compaction near roots, and don't wound trunks. When beetles are active, the only reliable control is prompt tree removal of infested trees to stop the spread to neighbors.
Emerald Ash Borer (Ash Trees)
The emerald ash borer (Agrilus planipennis) is an invasive beetle from Asia that has spread through Georgia and kills essentially every untreated ash tree it infests. Adults are metallic green; the damage is done by larvae tunneling under the bark and cutting off the tree's plumbing. The signature warning sign is a D-shaped exit hole about an eighth of an inch wide, paired with thinning from the top down (canopy dieback), water sprouts along the trunk, vertical bark splits, and heavy woodpecker activity stripping bark to reach larvae.
High-value ash trees can be protected with systemic insecticide treatments applied on a schedule, but treatment only makes sense if the tree is caught early and still in good condition. Once more than about half the canopy is gone, removal is the safer choice, dead ash becomes brittle fast and is dangerous to take down later.
Granulate Ambrosia Beetle
The granulate ambrosia beetle (Xylosandrus crassiusculus) is a tiny invasive beetle that hits young and stressed hardwoods, often ornamental and newly planted trees like maples, dogwoods, redbuds, and cherries. Its unmistakable sign is thin toothpick-like strands of compacted sawdust sticking straight out of the trunk, sometimes several inches long until they break off. The beetles bore in during the first warm days of spring and introduce a fungus that can wilt and kill smaller trees quickly. Keep young trees vigorous and avoid flood or transplant stress; severely infested saplings usually can't be saved and should be removed and destroyed.
Fall Webworm and Bagworms
These two are often confused but are very different pests. Fall webworm builds loose silken tents over the ends of branches in late summer on pecan, walnut, sweetgum, and many other hardwoods. It looks alarming but is mostly cosmetic on a mature tree. Small webs can be pruned out; large healthy trees rarely need treatment.
Bagworms are more serious, especially on evergreens like Leyland cypress, arborvitae, junipers, and cedars. Each caterpillar builds a spindle-shaped bag covered in bits of the host foliage, so it's easy to miss until needles start browning. Because evergreens don't refoliate well, a heavy bagworm year can kill a Leyland cypress. Hand-pick the bags in winter and spring, or treat with Bacillus thuringiensis while caterpillars are small and feeding.
Scale Insects and Aphids
Scale insects look like small bumps or crusty specks glued to twigs, leaves, and branches; they don't move and are easy to mistake for part of the bark. They suck sap and excrete sticky honeydew, which leads to black sooty mold and, over time, branch dieback. Crape myrtle bark scale has become a common nuisance across metro Atlanta. Aphids are soft, pear-shaped insects that cluster on new growth, curling leaves and coating everything below in honeydew, the reason your car under a tree turns sticky in summer.
Both are usually managed rather than cause for removal. Horticultural oils, soaps, and well-timed systemic treatments work well, and predators like ladybugs and lacewings often keep aphids in check. We worry about them mainly when an already-stressed tree is being weakened further.
Twig Girdler
If you find the ground under your oaks, pecans, or hickories littered with small fallen branch tips after late summer, the twig girdler (Oncideres cingulata) is the likely culprit. The female chews a clean groove around a twig so her larvae can develop in the dying wood, and the tip drops with a neat, beveled break. It's rarely a threat to a mature tree's health. The best control is sanitation: rake up and dispose of the fallen twigs to remove the larvae before they emerge.
Quick Reference: Georgia Tree Pests at a Glance
| Pest | Trees affected | Warning sign |
|---|---|---|
| Southern pine & Ips beetles | Loblolly, shortleaf, other pines | Pitch tubes, reddish boring dust, fading crown |
| Emerald ash borer | Ash | D-shaped exit holes, top-down dieback, woodpeckers |
| Granulate ambrosia beetle | Young maples, dogwoods, redbuds, cherries | Toothpick-like sawdust strands on trunk |
| Fall webworm | Pecan, walnut, sweetgum, hardwoods | Silk tents at branch ends in late summer |
| Bagworms | Leyland cypress, arborvitae, junipers | Spindle-shaped bags, browning needles |
| Scale & aphids | Crape myrtle, many shade trees | Bumps or clusters, sticky honeydew, sooty mold |
| Twig girdler | Oak, pecan, hickory | Cleanly cut twig tips on the ground |
Not sure if those holes, webs, or dropped branches are a real threat? Pests and disease often look alike, so it helps to also review our guide to common tree diseases in Georgia and the hazardous tree warning signs that mean a tree needs attention now. When in doubt, call our ISA Certified Arborists at (404) 426-8613 for a free estimate. We're fully insured and based right here in Austell.