During an outbreak, the southern pine beetle can cause extensive mortality to pine trees. Images: R.F. Billings, Texas Forest Service, bugwood.org; D.T. Almquist, University of Florida, bugwood.org (inset).
The southern pine beetle is a small insect capable of causing catastrophic damages in pine forests. In the past several years, “the most destructive pest in the South” has caused an estimated $1.5 billion in damages [Forest Heath Technology Enterprise Team report 2014].
The N.C. Forest Service monitors populations of the beetle each spring to determine the damage potential. Based on the spring monitoring period, a prediction can be made about whether we can expect an outbreak during the year or not. To monitor the southern pine beetle, funnel traps baited with pheromone lures are set in 14 areas across the state. The traps are set when dogwoods begin to bloom, a convenient cue which corresponds with the dispersal stage of the insect, or when they fly around in search of a new host tree to attack.
Each week, the insects captured in the traps are collected and the number of southern pine beetles and the number of its predator, the checkered Clerid beetle, are counted. By looking at the ratio of the predatory checkered beetle to its prey, we can predict if the southern pine beetle will be problematic in the coming months. Trapping is completed for 2014 and the N.C. Forest Service is busy counting beetles. Once this step is complete, a final report, including the prediction of whether the beetle will be in outbreak mode this year or not, will be released.
Funnel traps are used to trap the southern pine beetle and its predator, the checkered beetle. Image: K. Oten, N.C. Forest Service.
The southern pine beetle has cyclical outbreaks, meaning an outbreak typically occurs every 10-15 years. During the off years, the beetle has low population levels and only attacks trees weakened or stressed by other factors. The last southern pine beetle outbreak in North Carolina occurred in the western part of the state in the early 2000s.
To prevent attack, landowners and forest managers are encouraged to promote tree health, especially by maintaining proper stocking levels in pine stands. Stands that are thick and dense are at higher risk for attack. Landowners can take advantage of a cost-share program through the Southern Pine Beetle Prevention Program to help with the expenses of thinning a stand pre-commercially.
To learn more about this tiny insect that carries a big punch, visit N.C. State University’s Cooperative Extension Page.