TYLER, Texas (KETK) – All species of pine in the eastern half of Texas are prone to being attacked by Ips bark beetles.

According to the Texas A&M Forest Service, when prolonged drought occurs in the East Texas piney woods, an increase in Ips, or pine engraver beetle, activity is likely to occur. When trees are weakened or stressed due to drought or other conditions, engraver beetles may attack and kill a significant number of trees.

Almost any aged tree may be attacked, but generally, trees less than 10 years old may be killed by drought alone.

Identification

  • Ips beetles are cylindrical, black to reddish brown in color
  • Vary in size from 3/32” to ¼” in length
  • Can be identified by a scooped out rear end surrounded by spines

Immature adults, found under the bark, are usually yellowish to light brown. Fully-grown larvae and pupae are yellowish white and vary from 3/32” to 3/16” in length. Eggs are very small and white. All life stages (eggs, larvae, pupae, and adults) occur under the bark. They do not bore into the wood.

IPS Bark Beetle. Photo Courtesy of Texas A&M Forest Service.

Signs of Attack

Infested trees usually have numerous white to reddish brown pitch tubes, about the size of a wad of gum, on the bark.

In trees of low vigor, pitch tubes may be lacking and the earliest signs of attack will be reddish boring dust in bark crevices at eye level.

“Y-” or “H-” shaped egg tunnels are constructed in the soft inner bark parallel with the grain of the wood, and are mostly free of boring dust. The distinct gallery pattern is used for identification purposes even when larvae and adults are absent.

Habits

Adult beetles are attracted to weakened trees and chew round holes through the outer bark into the cambium layer.

Larval galleries increase in width as the larva grows in size. Egg galleries are a constant width because the adult beetles never increase in size.

Larvae mature, pupate, and transform to adults in 25 to 40 days, depending on the temperature.

Control

Predators, parasites, diseases, and starvation take a toll on Ips beetles, but usually not until the tree is beyond saving. These factors, plus changes in weather conditions, and proper harvesting practices can reduce Ips attacks and timber losses.

Salvage cutting and good forest management are the most practical control measures. High value trees can be sprayed with an approved insecticide, but the entire bark surface must be covered for control to be effective.

For more information, contact Texas A&M Forest Service or your county extension agent.