If I were to ask you what is most likely to destroy forests here in the western United States the natural answer would be wildfires, right? Nope! Bark beetles are actually responsible for more forest devastation than all wildfires combined (according to this forest service report). Not only that but this devastation can produce more fuel for future fires as well. Bark beetles are a natural part of the forest environment and can bee seen as helpful because killing trees in small numbers ensures groves don’t get overcrowded, however major outbreaks of bark beetles will kill trees indiscriminately and decimate huge swathes of forest at a time.
How does a tiny beetle kill a huge tree?
Close-up and size comparison
Bark beetles are small, typically 1/8 to 1/6 of an inch long depending on the species, however, these tiny insects can decimate even the largest of trees. They start by infesting the tree and getting under the bark into the phloem layer. There they bore inside and produce larvae. These larvae then hatch and continue to feed on the vital phloem layer of the tree. This process can essentially girdle the tree, creating a sort of ring where nutrients cannot pass, which is why the trees tend to die from the top down. Some species also bring along with them a type of fungus called “blue stain” that inhibits transport of water within the tree.
Why my trees?
When bark beetles are in small numbers they typically only target dead or weakened trees, but when populations explode due to environmental factors they can and will target healthy trees leading to large stands of trees being killed. The most prevalent types of bark beetles in Utah are the Spruce beetle, Mountain Pine Beetle, and Douglas Fir Beetle. All these beetles only target pine trees (which makes sense as they need a thick bark to burrow underneath), so other types of trees are safe from these infestations, but if you have pines on your property there is really no telling which year is going to be a bad year for bark beetle attacks.
What are the signs of a bark beetle infestation?
Pitch tubes at the base of a tree
There are some signs of infestation that you can look for in your pine trees. Sawdust at the base of the tree and/or in the crevices of the bark from the beetles boring into the tree, also small holes (referred to as “shot holes”) where they have entered. Another sign of distress from bark beetles are small popcorn-like masses of sap called “pitch tubes” (although these may not present in dry years). If you see these signs it doesn’t always mean the tree is done for, as it sometimes takes several re-infestations to kill a healthy tree, but it definitely means that a treatment is needed not only on that tree, but all trees on the property, as you now know that the beetles are in the area!
An example of shot holes
What can be done?
Luckily there is a solution to bark beetles. Utah State University recommends the use of a type of chemical called pyrethroids (which we use here at Newby’s) to combat beetle infestations. The best time to apply these treatments is BEFORE trees are mass attacked, so the treatment is a preventative measure, as there are no chemicals in use today that can reliably save trees after they are infested. These treatments are applied to the trunk, major limbs, and any exposed roots of the tree to kill the beetles before they can even enter the tree. There is also a fungicide component to combat the blue stain fungus mentioned earlier in the article.
Conclusion
Hopefully this article taught you something about these incredibly destructive pests! Scientists warn that bark beetle attacks may get worse over time in the western US so treatment is prudent especially if you hear about attacks in your area. Brain Head, Duck Creek, Mammoth Creek, and Panguitch Lake have all had bark beetle issues in recent years so If y0u have property in a mountainous region, or if you’re just curious about what’s going on with your trees at lower elevations, do not hesitate to call Newby’s Pest, Lawn, & Weeds at 435-586-7337 and set up a free estimate, or click on the button below to use our web form.
