Southern pine beetle (Dendroctonus frontalis) kills loblolly pines, shortleaf pines, and other southern pines by mass-attacking trees and introducing a blue-stain fungus that blocks water transport. A single infested tree can produce tens of thousands of beetles that spread to adjacent pines within days. In Upstate SC residential and suburban settings, a missed infestation can cost a homeowner multiple trees — and sometimes a stand. The signs are specific and identifiable if you know what to look for.
How to Identify Southern Pine Beetle
- Pitch tubes: small masses of hardened resin on the outer bark, popcorn-sized, yellowish-white to reddish-brown — the tree's attempt to pitch out the attacking beetles
- Boring dust: reddish-brown sawdust-like frass at the base of the tree or in bark crevices
- S-shaped galleries under the bark — visible if you pull back bark sections on a recently dead tree
- Crown yellowing starting at the top of the tree and progressing downward — needles turn yellow, then red-brown
- Blue-black staining of the sapwood when cut — the blue-stain fungus introduced by the beetles
How Southern Pine Beetle Attacks
Southern pine beetle attacks happen in mass — individual beetles release aggregation pheromones that recruit hundreds or thousands of additional beetles to the same tree simultaneously. A healthy pine can pitch out a small number of beetles (as evidenced by pitch tubes). When attacks are heavy enough to overwhelm the tree's resin defense, the beetles succeed in girdling the cambium layer and introduce Ophiostoma minus, a blue-stain fungus that further blocks the tree's vascular system. From the point of successful mass attack to crown death in loblolly pine runs 4–8 weeks. The beetles then move to adjacent pines, creating the expanding "spot" pattern visible from aerial survey. In Upstate SC, outbreaks typically occur during drought years when trees are water-stressed and their resin defenses are reduced.
What to Do When You Find Pitch Tubes
If you find pitch tubes on a pine, the response depends on the stage of infestation. Fresh pitch tubes with live boring activity: call for an assessment immediately. Trees with live beetles can still spread the infestation to adjacent pines. Rapid removal is the most effective way to prevent spread — remove and chip the infested tree before the emerging brood can fly to new trees. Dead pines with red-brown needles still attached: the infestation has run its course in that tree, but the tree is now a structural hazard and should be assessed for removal. Do not attempt to treat a tree under active attack with insecticides — systemic treatments are not effective once mass attack is underway. Preventive trunk injections (emamectin benzoate) can protect high-value individual pines from future attack but must be applied before infestation.
Tree Removal of SPB-Infested Pines
Loblolly pines killed by southern pine beetle are structurally hazardous — the wood dries and becomes brittle within months, and the root plate integrity is often compromised by the same stress conditions that made the tree vulnerable. Removal of dead or dying SPB-infested pines near structures or in areas with foot traffic should not be delayed. Martin Tree and Turf Care has removed SPB-infested pines throughout Spartanburg County and the suburban corridors around Greer and Boiling Springs where loblolly pine density is high. Adjacent-tree assessment is part of every SPB removal job — we look at the neighboring pines for pitch tubes before leaving.