Authored by: Dr. Elizabeth McCarty Southern pine beetle (SPB) is a small native beetle that can cause a widespread damage in pine forests. SPB bore into pine trees and feed on the tree’s vascular tissue right under the bark. Female SPB will enter the tree and dig tunnels to lay their eggs. Once the eggs hatch, the larvae excavate their own tunnels, feeding on tree tissues and destroying the vascular tissues that deliver starches and carbohydrates from the leaves to other parts of the tree. SPB outbreaks (also called SPB spots) occur when multi-acre swaths of pine forest become infested with SPB, which results in sometimes very large stands of dead trees. Normally, SPB occurs in low levels attacking stress-weakened trees, but when SPB populations increase to epidemic levels, they will begin attacking healthy pine trees. The number of SPB spots across Georgia have been lower since the mid-1990s, however, outbreaks have been increasing in the state in 2023 and 2024. In 2023, the Georgia Forestry Commission (GFC) documented 273 SPB spots, which was a surprising increase from recent years, and in 2024 there have been over 1600 SPB spots. Southern pine beetle pitch tubes. Photo credit: Elizabeth McCarty, University of Georgia Knowing SPB signs and symptoms can help landowners diagnose an infestation. The most noticeable symptom is a fading crown that goes from green to yellow to red to brown. Ultimately the needles will fall from the tree canopy. Sometimes the needles will even drop to the ground while they are still green. Trees produce thick sticky sap, or pitch, which will exit the trees where the adult beetles bore into the bark. The pitch accumulates in a popcorn-sized “pitch tube” on the outside of the bark. SPB pitch tubes can often be observed in the bark crevices between the bark plates. Once SPB-attacked trees begin declining, other pest insects will move in to feed on the trees, so signs of many different insects may be visible all at once. Not every dead pine tree is a SPB-attacked tree, so look for the pitch tubes located in bark crevices, which is an important sign of SPB infestations. Identifying a SPB infestation early is critical to reduce damage and financial losses. If you suspect a SPB infestation on your property, reach out to qualified professionals for assistance. In pine stands, SPB-infested trees, along with a buffer of uninfested trees should be cut to stop the outbreak. Georgia Forestry Commission can provide landowners with guidance for managing SPB spots, so please reach out to your county foresters for support: https://gatrees.org/gfc-contacts/county-contacts/ For homeowners, dead trees can pose a safety risk to people and property. Dead pine trees should be removed by a qualified professional. Additional information can be found in a recently published GFC-UGA outreach publication, available at: https://resources.ipmcenters.org/resource.cfm?rid=46253.
