Beetles killing trees
Stress is a common factor in human life, it can lead to ulcers, high blood pressure and the occasional ice cream binge, but stress on trees leads to an infestation of beetles, which is far more deadly than a quart of rocky road.
Dead, dying and stressed by Hurricane Katrina, local pine trees are facing more problems than droughts and fires, they are being infested by two destructive beetles, the Southern Pine and Ips beetles. Given a high enough concentration of dead or dying trees either of these beetles can produce a high enough population to kill healthy trees in the area said Terry Tetzlaff. Tetzlaff owns a forestry consulting business with an office in Poplarville and he said he’s noticed a number of pine trees that are becoming infested with the small beetles, he said. Extension Forester with the Mississippi State University Extension Service, Glenn Hughes said that the main culprit is the Ips beetle, which is only slightly different from the Southern Pine Beetle in appearance and boring habits but each are no larger than half a grain of rice. Hughes was able to determine this through the use of traps, and the number of Ips beetles was far larger, he said.
While the Southern Pine beetle is the most destructive, Hughes said he has not seen a major increase in the number of them in the southern part of Mississippi, which is possibly attributed to the high temperatures. The beetles are not choosy on the kind of pine tree they will infest either, while long leaf pines are most resistant to infestation they are still susceptible, Hughes said.
Tree stress can be caused by lightning strikes, droughts, over population of trees or high winds, which makes them more susceptible to infestation, Hughes said. Lightning strikes and droughts hinder a tree’s production of enough sap to push the bugs out like healthy trees do to fight off infestation, Hughes said. Those stressed trees then emit a chemical that female beetles pick up on before moving in, Hughes said.
After the female beetle detects a tree is stressed she will bore between the bark and wood making a system of tunnels, in loopy “S” shaped patterns for the Southern Pine Beetle and an “H” or “Y” shaped patterns for the Ips beetle, Hughes said. Once the female gains entrance into a tree she releases a chemical to attract other beetles, including males who build a separate chamber secluded from the rest of the beetle population, Hughes said.
Southern Pine and Ips beetles tend to stay higher in the trees, negating attempts at spraying them with insecticides but the black turpentine beetle, another destructive beetle, can be controlled with insecticides since they stay in the eight feet of tree closest to the ground, Hughes said. Usually the Southern Pine and Ips beetles will live between the first live branch to about halfway to the ground in the tree making insecticides hard to utilize, Hughes said. In the past there were chemicals that controlled the spread of the beetles, such as Lindane or Dursban, Hughes said. Production of each ceased when Lindane failed to sustain a high enough customer base while Dursban met with resistance from the Environmental Protection Agency, Hughes said.
“Only one way to control it, you gotta start cutting trees down,” Tetzlaff said.
Usually natural predators such as wasps and wood peckers keep the beetle population maintained, but the abundance of viable trees for infestation has produced an uncontrollable population, Tetzlaff said.
Tetzlaff sends a warning to those in the community that may be thinking they could just let nature take its course.
“Well nature sometimes does clear cutting.” Tetzlaff said.
Noticeable signs of beetle infestation include globs of sap on the outside of the tree, or saw dust material at the base of the tree which is caused by the Ambrosia Beetle, Hughes said.
“By the time people begin to realize the problem, it’s too far gone,” Hughes said. “Your probably best off taking that tree out.”
Removal should be conducted before the cool fall and winter months increase beetle activity as the summer heat is keeping them from being highly active, Hughes said.
“I’m afraid it’s going to get worse before it gets better,” Hughes said.
Tetzlaff said in high infestation cases it would be better to start over and plant quality trees. Federal money is available for land owners who are willing to go through the application process. Programs such as the Emergency Watershed Protection Program, which is a 75 / 25 cost share program, are available to help landowners recover losses, Tetzlaff said. The land owner would cover upfront costs, but be reimbursed for 75 percent if approved, Tetzlaff said. Two other programs are also available to help land owners rebuild their woodland. All programs and how to apply are listed at http://www.tetzlafforestry.com/, then click on the link on the left hand side of the page entitled “Katrina Cost Share Information”.
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