All wood-destroying beetles have the same life cycle (see picture).
The adult female beetle lays its eggs on wood, usually in cracks, holes, junctions of wood elements, or even wormholes.
The eggs hatch into larvae that burrow into the wood, eating all the woody substance. Within a few months or years, depending on the type of insect, the larvae eat passages in the wood and increase in size. They leave behind characteristic tunnels in the wood and emit waste in the form of very fine granules, the so-called drill flour. The formation of such tunnels is detrimental to the structural strength of the timber elements. Because of the shape of the larvae and the tunnels they leave behind, such insects are given the common name “wood borers”.
When the larvae mature, they move to the surface of the wood and turn into pupae, just like caterpillars (wrap themselves in a cocoon).
Finally, an adult beetle emerges from the pupal chamber and bites through the wood to reach the surface, leaving behind characteristic exit holes (wormholes). Next, the beetles find an appropriate partner, which further leads to the laying of eggs. After mating and laying eggs, the beetle dies and the life cycle begins again.
The size of the larvae, the length of time they spend in the wood, and the degree of destruction vary by species.
Some species prefer hardwoods, others only damage softwood sapwood, others choose wood that has begun to decompose under the influence of fungi.
Most often, beetles infect wood inside buildings, although in warmer climates they can also infect the outside.
Beetles are found throughout the world, but in tropical countries, termites are often a much greater threat as wood destroyers.
Furniture grinder (lat. Anobium punctatum)
This beetle is found in Europe, Iran, Canada, South Africa, Australia and New Zealand. Related species can be found in Japan.
As a rule, only the sapwood of softwoods, as well as hardwoods of temperate climates, is damaged. However, it can also attack the heartwood of various wood species where the heartwood is not distinct from the sapwood.
The larva at the last stage of growth reaches a length of about 6 mm, and the adult beetle – from 2 to 6 mm. As a rule, the life cycle lasts 3 years.
Brown barbel (lat. Hylotrupes bajulus)
This beetle is found mainly in the same regions as the furniture grinder, as well as in the United States. As a rule, only the sapwood of softwoods is damaged.
The larva at the last stage of growth reaches a length of about 30 mm, and the adult beetle – from 10 to 20 mm. As a rule, the life cycle lasts 7 years, but can be shortened (up to 1 year) or extended (up to 11 years) depending on the climate. Due to the large size of the larvae and the long life cycle, the scale of damage can be quite large.
Dark brown tree gnaw (lat. Lyctus brunneus)
This beetle and related species can be found almost all over the world. It is reliably known that it is distributed in North and South America, Europe, India, Southeast Asia, China, Japan and Australia.
Damages hardwood sapwood with a wide-pore structure suitable for egg-laying and high starch content. Most often, the pest lives in timber yards, but infestation by these parasites can often be observed in buildings as a result of the use of affected wood.
The larva at the last stage of growth reaches a length of about 6 mm, and the adult beetle – 5 mm. As a rule, the life cycle is 1-2 years, but can be reduced to 8 months.
|Furniture grinder (lat. Anobium punctatum)
||Brown barbel (lat. Hylotrupes bajulus)
||Dark brown tree gnaw (lat. Lyctus brunneus)
These are social insects that live in colonies. They are sometimes called white ants. However, although they also lead a social lifestyle, they are not ants. Most often they are found on the planet
within 40 ° N. sh. and 40°S sh., but sometimes they can be found closer to the north, for example in France. Termites infect wood, as well as many other cellulose-based materials, plants, etc.
Like other social insects, such as bees and ants, termites in a colony are divided into several castes. The queen (queen) is responsible for laying the eggs, the corresponding adult males mate with her, and the soldiers and workers guard and feed the colony, respectively. In one day, the queen can lay up to 4000 eggs.
Termites can attack wood both inside and outside buildings.
Termites can be divided into three large families.
These are species that nest in the ground and form huge termite mounds seen in some countries. In search of food, they travel great distances, building closed tunnels between the nest and food.
Wet Wood Termites
They mostly nest underground in close proximity to wood because they need contact with the ground, but can also nest in the wood itself if necessary.
Dry Wood Termites
These termites are independent of the ground and nest in dry, quality wood. Adult termites, having wings, fly out of the nest and create new colonies.
In most cases, termites consume the wood completely, leaving only a thin outer layer of healthy wood to protect them from the weather. Therefore, defeat can be difficult to notice until it reaches significant proportions.
These organisms live in salt water. As the scope of AkzoNobel’s wood preservative products does not include wood permanently submerged in water, only a brief description of these insects is given in this chapter for the sake of completeness.
They are divided into two main types.
These are small crustaceans that create many small furrows on the surface of the wood. Under the influence of waves, these furrows ultimately lead to erosion of the surface of the wood and the exposure of new healthy layers, which are again affected by limnoria. Gradually, the structure of the wood is corroded.
Belongs to the family of molluscs. It is a soft, worm-like creature with hard, boring jaws. Small, free-swimming larvae attach themselves to wood and then bore tunnels through it. The diameter of the channels increases with the growth of the worm. The worm does not leave the wood. It must maintain contact with water, which means that it grows both in width and length. An adult teredo can reach a length of several centimeters to a meter.