Interesting facts about wood pests
Common rodent beetle (woodworm)
The common rodent beetle ( Anobium punctatum
), also called woodworm because of its active larvae. The larvae do not
attack fresh wood; this is referred to as a dry wood pest. If the
larvae are active, this can be recognized by the oozing wood/meat dust.
It is advisable to check the activity for a few days, as the larva takes
breaks from feeding. The larva prefers sapwood; heartwood is only
attacked in rare cases. The development time of the larva lasts in the
best case one year, in the worst case up to eight years. After its
metamorphosis, a beetle emerges from the chrysalis. This is sexually
mature immediately. The finished beetle is around 2.5 to 5 millimeters
long and is able to fly. This means he can look for new places to lay
his eggs, but he is very “at home” and prefers the wood in which he grew
up.
Pied rodent beetle / colorful poch beetle / knocking beetle
The colorful / mottled rodent beetle at
5 – 9 mm, it is the largest native rodent beetle. It
is considered a secondary pest because it will only attack wood that
has already been damaged, preferably oak, but also willow. But sometimes
also softwood. The scent of wood-destroying fungi attracts the beetles.
These eat both sapwood and heartwood, the main thing being that they
are infected with fungi. Its
offspring, the larvae, don't care; they aren't so picky; they eat
everything, whether it's sapwood or heartwood, fungal infestation or
not. For optimal development of the larvae, moisture and the associated
fungal infestation are crucial. Under the best conditions (25% wood
moisture and 21-26° C), the development from larva to beetle takes 1 – 2
years. Normally one assumes a development time of up to 6 years. The
adult beetle only lives for a very short time (2-3 weeks) and is
immediately able to fly. Its appearance, a dark brown beetle with
patches of yellow-gray hair, gave it its name.
Brown sapwood beetle
The brown sapwood beetle ( Lyctus brunneus)
is an immigrant and was first spotted in Germany in the 1950s. It was
spotted in other parts of Europe at the beginning of the 20th century;
its original home is Southeast Asia. The sapwood beetle has a very
narrow 2.5 – 8 mm long body. It comes in three different colors, red,
dark and yellow-brown. Its larvae are 4 - 6mm long and have three pairs
of legs. It belongs to the borer beetle family and particularly prefers
hardwoods. The beetles are active at dusk and are good fliers. To
develop, the larvae need wood that has a very high protein content and
is rich in starch (e.g. oak, walnut, elm, ash, etc.). The type of wood
doesn't matter; it doesn't matter whether it's sawn wood, raw wood,
plywood or even veneer. Common beech, maple and conifers, for example,
are little or not affected at all. These are low in starch and protein,
and this also applies to heartwood.
House longhorn beetle
The house longhorn beetle, also known as the longhorn beetle or large woodworm ( Hylotrupes bajulus),
belongs to the longhorn beetle family. When fully grown it reaches a
length of 8 – 26 mm. This species loves the warmth and only flies at
temperatures above 30° C. In Central Europe mainly from June to August.
Its territory is coniferous forests, including pine, spruce and larch.
Sapwood is its preferred food, but heartwood is only very rarely
attacked. Hardwoods, on the other hand, are avoided. A house buck
infestation is very difficult to detect because it clogs the passages
with the meal. Feeding noises, fresh exit holes and the discovery of
larvae or beetles indicate an infestation. The larva itself only thrives
when the wood has a moisture content of 12%, ideally 30%. These
conditions are mainly found in roof trusses or in exposed wood, such as
utility poles, fence posts or wooden and half-timbered buildings. They
are ivory white and approximately 30 mm in size. The outer edge of the
wood remains undamaged; nutrient-rich sapwood is preferred. Under
favorable conditions the development time takes 3 – 4 years; under
unfavorable conditions this can be tripled. The emerging beetles leave
behind oval exit holes with a longitudinal diameter of 5 – 10mm. This
has a short lifespan of around 4 weeks and no longer eats food.