Asian longhorned beetles, spongy moths, citrus longhorned beetles — at times, it seems like there’s a never-ending stream of invasive insects turning up in the U.S. and threatening our native trees. But fortunately for Metro Atlanta trees, most of these pests have yet to establish themselves locally.
However, there are a few exceptions.
Hemlock woolly adelgid has been a problem for decades, and another insect — perhaps the most destructive forest insect ever introduced to North America — is very much a threat homeowners and property managers must know.
Called the emerald ash borer (EAB), this destructive insect has been confirmed present in Dekalb and Fulton Counties since 2013, and it’s now established in most of the metro area. And unfortunately, it is likely to kill every Georgia ash tree that doesn’t receive preventive care.
We’ll explain everything you need to know about EAB and how to protect your trees below.
Emerald Ash Borers: The Basics
To understand the threat EAB represents, it’s important to familiarize yourself with the facts about this insect.
The Emerald Ash Borer: A Destructive Invasive Species
Known to scientists as Agrilus planipennis, EAB is a small, metallic-green wood-boring beetle that’s historically native to East Asia. First documented in the United States in 2002, the insect causes problems for ash trees in its native range, but it isn’t as destructive as it is in the U.S.
That’s partially due to the parasites and predators found in Asia, which help keep their population in check, as well as the defenses some ash tree species have evolved while living alongside the pest. Neither of these factors are at play in the U.S., hence the insect’s tendency to devastate ash populations.
And “devastate” is very much the right word — EAB has killed hundreds of millions of ash trees across the country, primarily in the Midwest and Northeast. In some places, ash trees have effectively disappeared.
The Emerald Ash Borer Lifecycle
It’s important to note that the adult beetles are not responsible for most of the damage the species causes. Adults do feed on ash tree foliage, but this rarely causes significant harm to mature ash trees. Instead, it is the grub-like larval stage that presents the threat.
After hatching from eggs deposited on the bark, EAB larvae tunnel beneath the bark, where they begin feeding on the tree’s vascular tissues. This disrupts the flow of water and sugars through the tree, leading to significant stress, wilting, and, eventually, death.
Ash Trees in Atlanta: Species Susceptible to Emerald Ash Borers
Although ash trees aren’t particularly common in the Metro Atlanta area, several species are native to the region and play important roles in local ecosystems. And because they’re not as common as some other trees in our area, most property owners are highly motivated to protect any ash trees they do have.
Some of the ash trees most commonly found in the Atlanta area include:
- White Ash (Fraxinus americana): Common in rich forests, white ash is highly susceptible to emerald ash borer and typically dies within a few years of infestation if not treated.
- Green Ash (Fraxinus pennsylvanica): Often found in floodplains, stream corridors, and some landscapes, green ash is another preferred host and is readily attacked by emerald ash borers.
- Blue Ash (Fraxinus quadrangulata): Found in North Georgia, the blue ash is susceptible to EAB, though some research suggests it may be more tolerant than other ash species.
- Pumpkin Ash (Fraxinus profunda): This uncommon species grows primarily in wetlands and floodplains, but it is another species that’s vulnerable to EAB.
Fortunately, EAB does not infest the oaks, maples, hickories, pines, sweetgums, or other tree species that make up most of Metro Atlanta’s urban and natural forests. However, for homeowners with mature ash trees on their property, early detection and proactive treatment are essential to preventing tree loss.
Tree Technicalities: Not All “Ash” Trees Are Vulnerable
All Georgia ash trees belonging to the genus Fraxinus are at risk from EAB, but there are several other trees that include the word “ash” in their name yet remain immune to the pest.
For example, prickly-ash trees (Zanthoxylum clava-herculis), ash-leaf maples (Acer negundo), and mountain-ash trees (Sorbus americana) all feature “ash” in their name, despite not being closely related to “true” ashes of the genus Fraxinus.
Accordingly, none of these species are at risk from EAB.
Signs of Emerald Ash Borer Infestations
One of the biggest challenges with EAB infestations is that by the time obvious symptoms develop, the tree has often been infested for several years and essentially beyond help.
Common signs of an EAB infestation include:
- Canopy Thinning: The upper canopy is often the first part of the tree to decline. Leaves may become sparse, branches begin to die back, and the canopy gradually loses density.
- Epicormic Sprouting: As the tree becomes stressed, it may produce clusters of new shoots along the trunk or major branches in an attempt to replace its declining canopy.
- Bark Splits: Vertical cracks may develop in the bark as the tree responds to larval feeding beneath the surface, potentially exposing winding larval galleries beneath the split bark.
- D-Shaped Exit Holes: Adult emerald ash borers leave distinctive D-shaped exit holes about 1/8 inch wide when they emerge from the tree.
- Woodpecker Activity: Woodpeckers frequently feed on emerald ash borer larvae beneath the bark, potentially making increased woodpecker activity an early indicator of infestation.
- Serpentine Larval Galleries: Removing loose bark may reveal winding, S-shaped galleries etched into the wood by feeding larvae.
Emerald Ash Borer Treatments
Unlike many invasive tree pests, EAB can sometimes be managed successfully, as long as treatment begins before the tree has declined too far.
A few of the most common management strategies include:
- Routine Monitoring: Regular inspections help identify emerald ash borer infestations before significant canopy decline occurs. Because early symptoms can be subtle, professional evaluations are often recommended for mature ash trees.
- Preventative Insecticide Treatments: Systemic insecticides are the most effective way to protect valuable ash trees. Trunk injections containing emamectin benzoate typically provide the best long-term control, as the treatments often last for two or more years.
- Removing Severely Declining Trees: Once an ash tree has suffered extensive canopy loss, insecticide treatments are unlikely to restore its health. In these cases, removal is often the safest and most practical option, particularly if the tree poses a risk to people or property.
If you have an ash tree on your property, having it evaluated early can help determine whether preventative treatment is appropriate and give you the best chance of preserving it.
Emerald Ash Borers in Georgia: Frequently Asked Questions
Most invasive tree pests leave homeowners and property managers with questions, and EAB is no exception. Here are a few of the most common questions our clients have about the pest and protecting ash trees.
How do I know if I have an ash tree?
Ash trees have opposite branching, compound leaves with 5–11 leaflets, and diamond-shaped bark ridges on mature trees. Because several other trees have similar characteristics, it’s not always easy for homeowners to identify them. An ISA-certified arborist can confirm whether a tree is an ash and determine whether it’s at risk.
Can an ash tree survive an emerald ash borer infestation?
Yes—but timing is critical. Healthy trees and those in the early stages of infestation can often be protected with systemic insecticide treatments. Once a tree has suffered extensive canopy decline, treatment is much less likely to succeed.
How quickly do emerald ash borers kill ash trees?
The timeline varies depending on the tree’s health and the severity of the infestation, but untreated ash trees typically die within two to four years after becoming infested. Because emerald ash borers often go undetected during the early stages, trees may already be well into the infestation by the time symptoms become obvious.
Do emerald ash borers attack other tree species?
No. Emerald ash borers are highly specialized insects that attack ash trees (Fraxinus spp.). While they have occasionally been found on white fringetree, they do not pose a significant threat to oaks, maples, hickories, pines, sweetgums, or most other trees commonly found in Metro Atlanta.
Should I treat my ash tree before I see symptoms?
In many cases, yes. Preventative treatment is generally more effective than waiting until obvious symptoms develop. If emerald ash borers are known to be active in your area and your ash tree is healthy, an arborist can help determine whether proactive treatment is appropriate.
What happens if I don’t treat an infested ash tree?
Without treatment, emerald ash borers almost always kill North American ash trees. Most die within two to four years of becoming infested, although the exact timeline depends on the tree’s health, size, and the severity of the infestation.
Should I remove my ash tree as a precaution?
Not necessarily. Many healthy ash trees can continue to thrive for years with appropriate treatment. Removal is generally recommended only when a tree is in advanced decline, poses an unacceptable risk, or treatment is no longer practical or cost-effective.
Start Protecting Your Ash Trees Today
Emerald ash borers have already established themselves in Metro Atlanta, but they don’t have to mean the end of every ash tree. When infestations are identified early, proactive treatment can often keep high-value trees healthy for years to come.
If you think you have an ash tree on your property, the ISA-certified arborists at AKA Tree Service can inspect your tree, confirm whether it’s an ash, evaluate its condition, and recommend the most appropriate course of action.
Schedule your consultation today and take the first step toward protecting your ash trees before it’s too late.
Sources and References
- USDA Forest Service – “Georgia Forest Health Highlights 2024”
Annual statewide forest health monitoring report covering insect, disease, and invasive species conditions in Georgia, including emerald ash borer (Agrilus planipennis) status.
https://www.fs.usda.gov/foresthealth/docs/fhh/GA_FHH_2024.pdf - University of Georgia Extension – “Emerald Ash Borer Found with a Foothold in North Georgia”
UGA CAES Field Report covering the confirmed establishment of Agrilus planipennis in north Georgia and its implications for the state’s ash population.
https://fieldreport.caes.uga.edu/news/emerald-ash-borer-found-with-a-foothold-in-north-georgia/ - Southern Forest Health – “Emerald Ash Borer Updated Range Map”
Regional forest health program’s updated map tracking the spread of Agrilus planipennis across the southern United States, including Georgia.
https://southernforesthealth.net/news/emerald-ash-borer-updated-range-map - Trees Atlanta – “Emerald Ash Borer Spotted in Georgia”
Community urban forestry nonprofit’s alert on the detection of Agrilus planipennis in Georgia and the threat it poses to the region’s ash trees.
https://www.treesatlanta.org/news/emerald-ash-borer-spotted-in-georgia/ - Walter Reeves – “Emerald Ash Borer in Georgia”
Consumer gardening resource covering Agrilus planipennis identification, its detection in Georgia, and homeowner treatment options for ash trees.
https://www.walterreeves.com/insects-and-animals/emerald-ash-borer-in-georgia/
