Insect infestations are among the leading causes of tree death in Georgia, and they often progress quietly before the damage becomes obvious. A pine can go from green to fully dead in a matter of weeks once a bark beetle population establishes. An ash tree can lose its entire crown before a homeowner realizes an invasive borer has been working through the trunk for two seasons.
This guide covers the five most damaging tree insects active in the Smyrna and Cobb County area, how to identify an infestation early, and what to do when you find one.
The 5 Most Damaging Tree Insects in Georgia
1. Southern Pine Beetle (Dendroctonus frontalis)
The most destructive forest pest in the southeastern United States. Once a Southern Pine Beetle population establishes in a tree, the outcome is typically fatal.
Trees affected: Loblolly pine, shortleaf pine, and slash pine. These are the dominant pine species in Cobb County.
How it kills: The beetle bores into the bark and creates S-shaped galleries under the surface, cutting off the tree’s ability to move water and nutrients from roots to crown. It also introduces a blue-stain fungus that accelerates the kill.
What to look for:
- Small (1/8-inch) reddish-brown beetles on or around the trunk
- S-shaped winding patterns visible when bark is peeled back
- Pitch tubes: small masses of resin on the outer bark where the tree attempted to push the beetles out
- Yellowing or browning needles starting at the crown and moving downward
- Sawdust (called frass) accumulating at the base
What to do: Remove infested trees immediately. Active infestations spread to adjacent pines. Leaving an infested tree in place puts every pine on your property at risk.
2. Emerald Ash Borer (Agrilus planipennis)
An invasive species from Asia, the Emerald Ash Borer has killed hundreds of millions of ash trees across North America since its U.S. discovery in 2002. It is spreading into Georgia.
Trees affected: All native North American ash species (Fraxinus spp.). Identify your ash trees now if you have them.
How it kills: Larvae bore under the bark and create serpentine (winding) galleries that girdle the tree, cutting off nutrient flow. Infested trees die within 2-4 years of first attack, sometimes faster.
What to look for:
- D-shaped exit holes about 1/8 inch wide in the bark (this is the most distinctive sign)
- Serpentine larval galleries visible under peeled bark
- Crown dieback starting at the top of the tree and progressing downward
- Epicormic shoots (new sprout growth along the lower trunk): the tree’s stress response
- Bark splitting as larvae tunnel beneath it
What to do: There is no effective treatment once an infestation is well established. Preventive insecticide treatments exist for uninfested ash trees in high-risk areas; consult a certified arborist for that evaluation. Confirmed infested trees should be removed to prevent spread. [FLAG: Emerald Ash Borer confirmed presence in Cobb County and surrounding Georgia counties — verify current distribution with Georgia Forestry Commission before publishing]
3. Ambrosia Beetles (including Xylosandrus spp.)
Ambrosia beetles are early-season insects that attack stressed or weakened trees. They are secondary invaders: they don’t kill healthy trees, but they accelerate decline in trees that are already struggling.
Trees affected: A wide range of hardwoods and some softwoods, including dogwood, redbud, sweetgum, and many ornamental species common in Smyrna and Vinings yards.
How it kills: Unlike bark beetles, ambrosia beetles bore into the wood itself and cultivate fungal gardens inside the galleries. The fungus blocks the tree’s vascular tissue, causing dieback.
What to look for:
- Small circular entry holes (1-2 mm diameter) in the lower trunk
- “Toothpick” frass structures: thin tubes of compacted sawdust protruding from entry holes (highly diagnostic for ambrosia beetles)
- Wilting or dieback in affected branches
- Stressed trees that were already showing decline from drought, flooding, or root damage are the primary targets
What to do: Address the underlying stress first (watering, mulching, soil aeration). Vigorous trees rarely succumb to ambrosia beetles alone. If the tree is in serious decline despite stress reduction, assess it for removal.
4. Bark Borers (Shothole Borers and related species)
A general category of beetles that bore into the bark layer of weakened or stressed trees. Common species in Georgia include the flatheaded appletree borer and various Scolytid beetles.
Trees affected: Stressed oaks, fruit trees, ornamental trees, and conifers.
What to look for:
- Round to oval exit holes in the bark
- Frass (powdery sawdust) in bark crevices and at the base of the tree
- Stained or weeping areas on the bark around entry holes
- Branch dieback, often beginning in the upper or outer crown
What to do: Bark borers rarely kill healthy trees on their own. The priority is improving tree health: deep watering during drought, 3-4 inches of mulch over the root zone kept away from the trunk, and removing any damaged or crossing branches that stress the crown.
5. Scale Insects (various species)
Scale insects are sucking pests that attach to bark and twigs and feed on the tree’s sap. They are slower-moving than bark beetles but can cause significant dieback over time, particularly on ornamental trees.
Trees affected: Oaks, hollies, camellias, dogwoods, magnolias, and Japanese maples are common hosts in Cobb County yards.
What to look for:
- Waxy, armored, or cottony bumps on twigs and bark
- Yellowing leaves or premature leaf drop
- Sticky, shiny residue (honeydew) on leaves and surfaces beneath the tree
- Sooty mold (black fungal growth) on honeydew deposits
What to do: Light infestations can be treated with horticultural oil sprays applied during the correct growth stage. Heavy infestations may warrant professional treatment or, if the tree is severely weakened, removal assessment.
How to Identify an Infestation Early
Sign | What It Likely Means |
|---|---|
Small round holes in the bark | Bark borer or beetle entry/exit |
D-shaped holes in the bark | Emerald ash borer (ash trees only) |
S-shaped patterns under the bark | Southern pine beetle galleries |
Toothpick frass tubes at entry holes | Ambrosia beetle (diagnostic) |
Sawdust accumulating at the tree’s base | Active boring activity |
Needles browning from the crown downward | Southern pine beetle or severe root stress |
Crown dieback starting at the top | Emerald ash borer or root girdling |
Sticky residue on leaves below | Scale insect honeydew |
Can an Infested Tree Be Saved?
It depends on the insect and how far the infestation has progressed.
Southern pine beetle: Once the infestation is active and galleries encircle the trunk, the tree will not survive. Remove it promptly to protect adjacent pines.
Emerald ash borer: No reliable treatment exists once the infestation is well established. Preventive treatments for uninfested ash trees in high-risk zones are available; ask a certified arborist. [FLAG: verify current treatment guidance with Georgia Forestry Commission]
Ambrosia beetles: If the tree is otherwise healthy and the infestation is caught early, reducing stress (water, mulch, drainage) can allow the tree to recover. Severe infestations in already-declining trees rarely reverse.
Scale insects: Early-detected scale infestations are treatable with proper horticultural oil applications at the right time of year. Severe infestations on a weakened tree may warrant removal.
For a broader look at the signs that a tree is past the point of recovery, see our post on signs your tree is dying.
When to Remove an Infested Tree
Remove the tree when:
- An active Southern Pine Beetle infestation is confirmed: delay spreads it to adjacent trees
- The infestation has already caused more than 50% structural decline
- The tree poses a safety hazard regardless of the insect present
- The species is an ash tree with confirmed Emerald Ash Borer galleries
For timing and what the removal decision looks like in practice, our post on signs it’s time to remove a tree covers the factors we look at.
What to Do With the Wood After Removal
This step matters for stopping the spread:
- Do not move infested pine firewood off the property. Moving it spreads bark beetles to new areas.
- Do not chip infested Southern Pine Beetle material and compost it on site.
- For emerald ash borer-infested trees: follow current Georgia Forestry Commission guidelines on disposal. Restrictions may apply in quarantined counties. [FLAG: verify current Cobb County quarantine status before publishing]
Frequently Asked Questions
How do I know if my pine tree has southern pine beetles? Look for pitch tubes on the outer bark: small, popcorn-like masses of resin where the tree tried to push the beetles out. Peel back a small section of bark at the resin mass and look for S-shaped galleries running through the inner bark layer. Yellowing needles starting at the crown are a follow-on sign. If you see pitch tubes combined with browning needles, call for an inspection.
Can I treat an infested tree myself? For most bark beetles and ambrosia beetles, DIY treatment options are limited. The most effective intervention is improving tree health: water, mulch, and removing stress factors. Preventive insecticide treatments for Emerald Ash Borer require specific products and timing; a certified arborist should apply them. Once a Southern Pine Beetle infestation is active, no treatment stops it. Removal is the answer.
My tree has holes in the bark but looks otherwise healthy. Do I need to worry? Not necessarily. Old woodpecker feeding holes are round and are often mistaken for insect damage. Exit holes from long-dead infestations may also be present in trees that are currently healthy. The key indicators of an active infestation are fresh frass (new sawdust) at the holes, resin tubes, or a tree that is declining in the crown. If you’re not sure, an on-site look will tell you more than a photo can.
Does homeowner’s insurance cover tree removal after an insect kill? Standard homeowner’s insurance generally does not cover tree removal due to insect infestation or disease unless the tree has already fallen and caused covered property damage. Check your policy. A documented inspection by a tree professional supports any insurance claim that does apply.
Schedule a Tree Inspection in Smyrna and Cobb County
If you’re seeing entry holes, sawdust, or unexplained crown dieback, have it looked at before the infestation spreads.
Tree Service Smyrna serves Smyrna, Marietta, Vinings, Mableton, and Austell. Call 470-994-5343 for a free tree inspection. Family owned and fully insured.
If the tree turns out to be healthy, you’ll know. If an infestation is active, you’ll know that too, and you’ll know the options before it gets worse.
Sources
- Georgia Forestry Commission, Southern Pine Beetle Information: gatrees.org [FLAG: verify specific page URL before publishing]
- UGA Cooperative Extension, Identifying and Managing Bark Beetles in Georgia: extension.uga.edu [FLAG: verify specific article URL before publishing]
- USDA Animal and Plant Health Inspection Service, Emerald Ash Borer Program: aphis.usda.gov [FLAG: verify specific EAB page URL before publishing]
- Georgia Forestry Commission, Emerald Ash Borer in Georgia: gatrees.org [FLAG: verify specific EAB page and current distribution map URL before publishing]
