TYLER, Texas (KETK) – All pine tree species in the eastern half of Texas are susceptible to attack by Ips bark beetles.
According to the Texas A&M Forest Service, prolonged drought is likely to increase Ips, or pine engraving beetle, activity in East Texas pine forests. When trees are weakened or stressed due to drought or other conditions, stinging beetles can attack and kill a significant number of trees.
Almost any old tree can be attacked, but in general, trees less than 10 years old can be killed by drought alone.
- 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 hollowed-out rear end surrounded by spikes
Immature adults found under the bark are usually yellowish to light brown. Adult larvae and pupae are yellowish white and vary in length from 3/32 inch to 3/16 inch. Eggs are very small and white. All life stages (eggs, larvae, pupae and adults) occur under the bark. They don’t dig into the wood.
signs of an attack
Infested trees usually have numerous white to red-brown pitch tubes on the bark, about the size of a ball of chewing gum.
Pitch tubes may be absent on trees with low vitality, and the earliest signs of attack are reddish drill dust in bark crevices at eye level.
“Y” or “H” shaped egg tunnels are built into the soft inner bark parallel to the wood grain and are usually free of drill dust. The distinct gallery pattern is used for identification purposes even when larvae and adults are absent.
Adult beetles are attracted to weakened trees and eat round holes through the outer bark into the cambium layer.
The larval galleries widen as the larva increases in size. Egg galleries are of constant width as the adult beetles never increase in size.
The larvae mature, pupate, and transform into adults in 25 to 40 days, depending on the temperature.
Predators, parasites, disease and starvation all take their toll on ips beetles, but usually only when the tree is beyond saving. These factors, along with changes in weather conditions and proper harvesting practices, can reduce ips attacks and timber losses.
Salvage 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.
Contact the Texas A&M Forest Service or your County Extension Agent for more information.