Latin: Phymatodes testaceus
Among some of the most common insects in Denmark is the tanbark borer with the Latin name Phymatodes testaceus. The tanbark borer belongs to the genus of wooden borer. The members of this genus have long, curved feeler horns reminiscent of goat horn.
Appearance
When the tanbark borer is fully grown, it is between 10 and 15 millimeters long. Its breast usually has an orange color, while its coverts are characterized by a blue color. However, there are also variants of the tanbark borer, where their front part of the chest is instead brown or black, and where the wings are brown or yellowish.
The larvae of the tanbark borer are very similar to the other species in the borer beetle family. They all have a yellowish-white color, just as their bodies are clearly articulated. In addition, all the larvae have quite small legs. The larva’s head sits at the thickest end of the body, where there are powerful brown cheekbones.
Biology and behavior
The tanbark borer female lays her eggs in deciduous trees. And she most often chooses beech trees for the purpose but can also use either birch or oak. The eggs are placed in the cracks and crevices of the female using the female’s laying pipes. The female chooses dead, felled, or damaged trees with a bark for the placement of her eggs, as her larvae feed on the bast layer between bark and sapwood.
Therefore, it is also clear to see if a group of tanbark borer larvae have been at play in a tree. To remove the bark, their passages emerge clearly as small furrows in the wood. And you can even see small traces of the larvae’s cheekbones, which are marked as a faint streak. The passages are also full of drilling dust, which consists of the undigested parts of bark and wood from the larvae’s excrement.
The larval development normally takes about 2 years. The adult larva pupates in an L-shaped passage of 2-3 centimeters, which it gnaws itself. Once the larva has gone through the process from larva to adult tanbark borer, it goes back through the pupae. It then gnaws its way through the bark of the tree, leaving an oval fly hole with smooth edges of about 4 × 6 millimeters.
Damage
The tanbark borer lays its eggs in deciduous trees. This means that it is rarely to great damage in homes and other properties, where building timber and softwood are most often used. And should hardwood be used, this will probably be debarked.
When tanbark borer moves inside, their movements can almost always be traced back to a firewood pile outside. If you want to avoid tanbark borer appearing in residential areas, you should therefore move the stack of firewood far away from the house.
Worse is if tanbark borer attacks deciduous trees that are intended to be used for carpentry work. It can cause significant damage to the wood and thus financial loss. This is because the larvae leave pupae in the outermost part of the tree, making it unusable.
Prevention and pest control
Fortunately, it is one of the rarities that the tanbark borer is a big nuisance inside. Often, its presence in the home is since it has been transported inside through the firewood stack. Therefore, one should refrain from storing excessive amounts of wood inside at a time. If you want to make life miserable for the tanbark borer, you can make sure to peel the deciduous tree before storing it. The same method applies to an ongoing attack. Because once the bark is removed, beech larvae cannot survive.
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