These beetles are generally species specific - meaning they only infest a certain species of tree. Perhaps the most common borers in our area infest Red Oaks, Western Soapberry, and Ash trees. When infested, these trees may be badly scarred or killed.
Since Red Oaks are one of the most commonly planted landscape trees, we'll focus on Red Oak borers.
These beetles mate and lay eggs on stressed Red Oaks in late Summer just after they exit a host tree. These eggs hatch in early Fall and the larvae chew their way into the sapwood of the tree. They chew tunnels, feed and grow in this area of the tree until the following Summer when they burrow into the heartwood of the tree and begin their transformation into an adult beetle. When they mature they chew their way out of the tree and fly off to find a mate and a suitably stressed host tree for the next generation.
The holes left in late Summer typically ooze sap, which is often the first noticeable evidence of an infestation. Unfortunately, it also may be too late to treat the problem.
Evidence of a past or present infestation problem includes the following:
1) Small holes (1/8"-1/4") in lower part of tree trunk on the Southwest side of the tree. The heat from the sun provides a more favorable environment for the larvae on the Southwest side.
2) Bark begins to slough off this side of tree revealing dead tissue and exposed heartwood. This typically occurs well after the borers have left but should be treated to preserve the tree.
3) Limbs on infested side of tree turn brown and die back to trunk. This occurs due to the borer's disruption of the tree's vascular systen cutting off water to that side of the tree.
4) Canopy distress that is confined to the Southwest side of the tree.
Borer Treatment and Prevention
Borers can be treated with systemic chemicals to preserve the tree. The chemicals are applied at the base of the tree and absorbed into the vascular system, killing any feeding larvae and preventing future attacks by making the tree unattractive to the beetles.
These beetles are only attracted to trees that are under stress. Stress typically comes from extreme environmental conditions, such as drought, or newly installed trees that have not yet established in a new location. For this reason, if you suspect your Red Oak is exeriencing stress and may be attractive to borers it is best to treat it as a preventative. Heritage Tree Service of Texas has extensive experience in preventing borer infestations and treating for them in the Dallas/Fort Worth area.
Repair of Damage
It is possible to save your tree friom the damage done by borers. depending on the size and location of the infestation it may not be necessary to remove the tree and start over. It is critical to identify the infestation quickly and treat the problem thus minimizing the amount of structural damage to the tree. If the damage is not too extensive, the tree can be "disinfected" and repaired and allowed to heal safely on its own. Heritage Tree Service of Texas has experience in successfully repairing borer damage.