Many landowners in southeastern Georgia have seen their pine trees die this summer. Even if you were fortunate enough that the pines on your own property were spared, you may have noticed dying pines in clusters deep in the forest, or you may have spotted an individual dying tree in a yard or on the street.
If you observed the needles on these trees going from green to yellow to dead in a matter of weeks, the culprit behind these sudden deaths may have been the southern pine beetle.The SPB is a brownish to black beetle that is about the size of a grain of rice.
The beetle is a major pest to pine trees in the Southeast. Both adult and larvae SPB chew their way through the tree’s phloem of the tree that moves food from the leaves down to the roots and "girdle" the tree, preventing movement of nutrients. Adult beetles also carry a fungus that clogs the xylem and prevents movement of water. Many beetles attack a single pine at once, overwhelming the tree and leading to its death.
SPB infestations have been identified in 91 locations in Camden, Chatham, Charlton, Glynn, Liberty, and McIntosh counties in southeastern Georgia. During outbreaks, the SPB attacks healthy trees, affecting forests, neighborhoods, and recreational areas. The Georgia Forestry Commission (GFC) has identified SPB as the worst insect pest to pine timber in Georgia. Since forestry contributes $23.6 billion and over 100,000 jobs to the state economy, this threat to trees and forests should be taken very seriously.
SPB attacks can be identified by small yellow to white sap flows embedded or following the crevices or furrows of the bark plates. The first pitch flows will normally be in the furrows of the bark approximately 15 feet up the stem of the pine tree. These "pitch tubes" occur because the trees begin making more sap to trap the beetles. Since SPB outbreaks move quickly, killing pine trees in only a few weeks, proper action must be undertaken immediately once signs of an infestation are observed.
In southeastern Georgia, loblolly pine is very susceptible to SPB attacks. But what makes a tree susceptible? Simple: stress. When trees get stressed they are more likely to get attacked by insects and diseases. Trees can be stressed by droughts, overcrowding, or just old age. In any of these cases, trees are more likely to be attacked by insects such as the SPB.
While there isn’t much you can do about the age of your trees or the amount of rain that falls, you can help alleviate tree stress by properly managing your pines. Keeping weeds and unwanted trees out of your pine stand will give your pines the best access to valuable water and nutrients. Thinning your pine stand when it gets overstocked is the most important things you can do to prevent SPB infestations, as forest land that has been thinned is much less attractive to SPB.
Once SPB is present, the most effective way to stop an infestation is to harvest infested trees and cut a buffer strip to prevent further spread of the infestation. In residential areas, tree removal may be the only option.