Pine Borers
Important Facts about Pine Borers
Out of literally thousands of types of wood boring insects, one of the most common attackers of pine trees in the southeastern states are the pine borers, or pine bark borers. Out of this broad category arise a few of the most aggressive and damaging boring insects that threaten masses of pine trees.
The Southern Pine Beetle is one of the chief concerns of the pine trees in the southern states. As with almost all pine borers, it is the larvae of the beetle that causes the damage. Tunneling underneath the bark of pine trees and eating through the cambium layer, the pine borers effectively “girdle” the tree; cutting off nutrients that are necessary to the tree’s good health. Their burrowing path forms an “S” shape under the bark. Adding to that damage is the blue stain fungus the larvae introduce into the living tissue of the tree; further threatening its health. An indication of the pine borers presence are the pitch tubes which are formed when frass is eliminated through the tunneling process and forced out through tiny holes. The adult southern pine beetle is vigorous during the warm months of springtime; mating and depositing eggs in single fashion in wounds or cracks of trees. Most often affected are trees which are already under stress that may have resulted from disease, other insect invasion, lack of sunlight and lack of water. When the infestation of a forested area becomes severe, the pine borers broaden their attack to include healthy trees.
The black turpentine beetle produces another of the most dangerous pine borers, with a range reaching from New Hampshire down to Florida. These beetles are drawn by the smell of fresh pitch, which may result from a recent injury to a pine tree or newly cut stumps. These will be their primary target, and once infestation of the weak trees is complete, they will turn to healthy trees. While the attack of their larvae is very damaging to the pines, it is not always fatal. The beetles themselves bore holes into the pine bark, chewing tunnels into the cambium layer of the tree within 6 feet of the ground. The adult then deposits eggs in grooves made in the tunnels, which will hatch within 10 days or so as tiny grubs. Feeding begins immediately for these pine borers and proceeds for the next several weeks. The entire life cycle is only 3 to 4 months, but generations continually overlap to produce the utmost in damage to the tree.
Pine borers are a major concern in southeastern states, where pests such as the two described here attack pine forests. Avoiding tree injury and continuous inspections of susceptible trees are means of avoiding infestation of destructive pine borers.