North Carolina on alert as pine beetles devastate forests in other Southern states

An old nemesis of North Carolina's pine forests is having a resurgence in other Southeastern states as southern pine beetle outbreaks are decimating forest stands in parts of South Carolina and several Gulf Coast states.

And according to maps prepared by the U.S. Forest Service, counties around Wilmington are some of the most at-risk areas when the next beetle outbreak occurs in the Tar Heel State.

When that will be remains an unknown, although a general rule of thumb of experts is an outbreak occurs every seven to 10 years.

The last big outbreak in North Carolina was in the early 2000s.

According to the Clemson University's Southern Pine Beetle Information Center, outbreaks are irregular and hard to predict, stating they can be "frequent, severe and widespread," although recent activity has been "localized and short-lived."

Still, southern pine beetle infestations in 2023 represented "the most wide-spread activity in the Southern region in the past two decades," according to the information center.

Southern pine beetle 101

Although smaller than a grain of rice, southern pine beetles can devastate swathes of pine forests, feeding and eventually killing its preferred victims − southern and loblolly pines. While the beetles also attack longleaf pines, those trees are more tolerant of the bugs.

Often called the scourge of southern pine forests, the beetle seeks out already weakened or stressed trees to colonize.

Heather Moonier, forest health monitoring coordinator with the N.C. Forest Service, said pine beetles aren't usually the cause of a tree's troubles, but are what's commonly called a secondary pest.

Triggers for a tree's weakened or stressed state can include drought, damage from storms or logging, and competition with other trees or vegetation in areas that aren't properly managed − or often a combination of several of these factors.

"The beetles are just looking for stressed trees," Moonier said. "They are really coming in to put the last nail in the coffin, if that makes sense."

The female beetle arrives first, and then is joined by a male. Pheromones released by the pair then attract more beetles. Several generations of beetles, including larvae, then infect the tree.

"They interfere with the tree's ability to feed, starving them of water," said Dr. Jim Gregory, a retired forester with N.C. State University and a member of the Alliance for Cape Fear Trees.

Adults, larvae and eggs then overwinter in infected trees, starting the process all over again in the spring. During an outbreak, beetle numbers are so great that they can overcome the defenses of even healthy trees.

Signs of an infestation include popcorn-sized pitch tubes on the trunk and serpentine-shaped galleries as they feed under the tree's bark. Eventually, as the infestation spreads, pine needles will turn from yellow to orange.

What do I do if I have an infected pine tree?

Unfortunately, there isn't a lot that can be done once a tree has been attacked by the beetles.

"There is really no pesticide application that is effective," said Lloyd Singleton, director of the New Hanover County Cooperative Extension. "The best thing to do is remove the infected tree as soon as possible.”

While removing a single tree of might work for residential property owners, that isn't really an option for large forested tracts, whether on public or private land.

In that case, a large-scale removal of blighted trees might be required to stop the infestation, since some adjacent trees could be infected even if they're yet to show any signs.

The state forest service offers a cost-share program to help private landowners manage their stands to proactively prevent beetle infestations.

Is North Carolina facing an outbreak?

The short answer is no − at least this year.

While the bugs are around all the time, they are generally found at very low or nearly undetectable levels.

But every so often, bug numbers can surge. Moonier said the forest service does trap testing in the spring to gauge beetle population levels as they emerge from already sick trees to look for new targets.

"Based on our catches this spring, we determined there was a very low chance for outbreak this year," she said.

According to the Southern Pine Beetle Prediction website, Brunswick and Pender counties had a 0.2% chance of an outbreak in 2024, with spot infestations running at about 4%. The rest of the state had similar odds.

Other Southern states haven't been as lucky. According to the Alabama Forestry Commission, this is the most widespread outbreak that state has seen since 2001, with more than 5,000 infestation spots across the state and an average mortality of 191 pine trees per spot. The loss of timber threatens not only the wood supply for logging companies, but income for private landowners.

Other outbreak "hot spots" this year include counties in Mississippi, Georgia and South Carolina.

What role could climate change play?

With changing weather fueled by climate change, a warming environment could create a longer period for the bugs to stay active.

Climate change in North Carolina also is expected to bring periods of longer and more severe drought to the state, one of the primary triggers that can weaken pine trees and make them more susceptible to pests and diseases. Bigger and more powerful tropical storms that reach farther inland also could cause more damage to forests.

Warming temperatures also could allow southern pine beetles to push farther north into new areas. Already, the pests have been spotted in parts of New York.

A 2022 paper in Sciencedirect found the pine beetle to be "positively affected" by climate change, with warmer temperatures likely fueling geographic range expansions and enhancing outbreaks.

But the researchers cautioned that many variables, including local site conditions and tree growth, could ultimately determine what impact global warming has on the beetle.

Reporter Gareth McGrath can be reached at GMcGrath@Gannett.com or @GarethMcGrathSN on X/Twitter. This story was produced with financial support from the Green South Foundation and the Prentice Foundation. The USA TODAY Network maintains full editorial control of the work.

This article originally appeared on Wilmington StarNews: NC on alert as pine beetles devastate forests in other Southern states