insects
Los insectos están entre los organismos más comunes en la Tierra, y muchas de sus especies poseen la capacidad de utilizar la madera para abrigo o alimento. De los 26 órdenes de insectos, 6 causan daño a la madera. Termitas (Isoptera), escarabajos (Coleoptera), abejas, avispas y las hormigas (himenópteros) son las causas primarias de la mayoría de la destrucción en la madera.
El ataque del insecto es evidente, generalmente, por aparición de túneles o cavidades en la madera, que contienen a menudo polvo o aserrín (heces del insecto) de madera. La presencia de polvo al pie de la madera o aserrín sobre la superficie de la madera son muestras de un ataque.
Termites
There are 2000 species of termites that are distributed in areas where the average annual temperature is 10 °C or higher. In some cases, termites prolong their progression in cooler climates by living in warm man-made structures. They attack most wood species. Termites are social insects, organized into a series of classes that perform specific functions. The leader of the colony is a queen whose sole purpose is to lay eggs. The queen is protected by the soldiers and is strengthened and fed by the workers, who also build the nest and cause damage to the wood. Like all creatures, termites have certain requirements, including high moisture content wood, a convenient food source, a high level of carbon dioxide, and oxygen. Termite colonies range in number up to a million or more.
They implicitly attack any available wood, but require a source of moisture and typically a nest in the ground. They have developed the ability to attack wood above ground by building earth tubes that protect them from light and carry moisture to the wood. Wood damaged by subterranean termites have numerous tunnels through the spring wood but there is no exit hole to the surface to indicate the presence of termites. Often, a sharp tap on the surface of the wood will reveal that there is only a thin plate of wood debris. Termites' underground tunnels are filled with a mixture of debris and feces, giving them a dirty appearance.
They are common in the Pacific northwest, although a group is found in the more arid southwest. The most common dampwood species is found along the Pacific coast from northern California to British Columbia. Like subterranean termites, dampwood species need wood that is very wet, and their attack is often associated with damage. These insects are a problem for freshly cut lumber, utility poles, and any untreated wood that is in contact with the ground. The tunnels made by damp wood termites are quite large; like the subterranean species, they tend to avoid the harder summer wood. The tunnels often contain small amounts of sawdust, however the appearance of the wood is somewhat cleaner than that which is attacked by the underground species. Dampwood termite attack can be prevented or stopped by removing the source of moisture or using preservative-treated wood in situations requiring contact with soil.
They are differentiated from subterranean dampwood termites by their ability to attack wood that is extremely dry (5 to 6 percent moisture content). As a result, the attack of dry wood termites is not on pieces that have to be in contact with the ground and are also far from visible sources of moisture. Wood damage from these insects is long smooth tunnels that are free of sawdust or debris. Furthermore, there is no variation in attacks between spring wood and summer wood. Drywood termites frequently clean the nest by chewing on the tunnel surfaces, pounding and dislodging debris, in which infected wood accumulates below. Although the tunnels are resealed, the presence of debris beneath the opening is a good sign of attack. In general, clusters of infections are found in a geographic area, and prevention poses some difficulty. While an infection occurs, the use of structural fumigation has become widespread because it is effective. Fortunately, the drywood termite is confined to a relatively small geographic region.
Beetles
(Coleoptera) represent the largest order of insects that cause substantial damage to wood. Many beetles attack only living trees or cut fresh wood, but are easily combated as their damage can be found during inspection. The larvae of many of these beetles are called woodworm or quera.
They are insects whose larvae attack wood, leaving behind a series of small tunnels packed with excrement. The three families of wood-pulverizing beetles are anobids, bostrichids, and lyctids. These insects cause serious damage to wood and are a particular problem in museums, where wooden artifacts can go unnoticed for long periods. Anobids and bostrichids attack dead branches in damp wood but also attack untreated wood. The damage is worsened by adults that emerge by reinfecting the same piece. of wood.
It is found throughout the world in hardwoods and attacks those with a moisture content above 8 percent. The larvae of these beetles make the tunnel, and also expel the excrement out of the wood. These excrements accumulate at the foot of the affected wood and are a good sign of sprayer infection. The use of preservative treatments on the wood will prevent lyctide infection. However, wood pulverizer beetle attack can become a problem where untreated wood is used in older existing structures.
Also called flathead or metal wood borers, they are almost entirely dependent on trees completing their life cycle. They cause significant damage by attacking living trees, leaving damage that may be evident in lumber or other wood products. This beetle lays its eggs on the bark surfaces or in wounds of the tree. Over the course of their 1 to 3 year life cycles, larvae extensively tunnel in wood, leaving galleries packed tightly with their excrement. The mature larval pupae and the adult chew an escape through a hole forming the exit. In addition to the species that attack live trees, one species, the golden buprestid (Buprestis aurulenta) is capable of attacking live Douglas fir. This beetle causes serious damage to utility poles, where these attacks are often associated with extensive damage.
They include a number of wood degraders that generally have antennae longer than their bodies. They attack wood in all conditions, depending on the species, and cause substantial damage. Some, such as the sugar maple borer and the cottonwood borer, attack only living trees, killing them and reducing the value of the wood.
Dendroctonus ponderosae pierces the pine bark or its wood in recently cut specimens, rapidly degrading the wood.
An interesting attacker of greenwood is the powerful borer, whose larvae attack Douglas fir and pine, producing tunnels nearly an inch in diameter. Although this larva can complete its development in sawn wood, it does not reinfect previously attacked wood.
In addition to longhorn beetles that attack life in recently harvested trees, several species cause damage to serviced timber. Another species, the old house borer, is one of the most destructive wood borers and prefers dry coniferous wood.
carpenter ants
They differ from the insects previously described in that they use wood as shelter rather than food. They are social insects with a complex organization that revolves around the queen. To sustain the colony and raise their young, worker carpenter ants must cover long distances from their nest to obtain food, which may consist of insect secretions and sugary sources. As the colony grows from the original queen by about 100,000 members, the workers gradually enlarge their nest, causing serious internal damage to the wood.
carpenter bees
Like ants, Carpenter Bees use wood only for shelter and to raise their young. In this process, they make a tunnel along the fibers of coniferous woods, creating galleries 13 to 46 cm long by 0.8 to 1 cm wide. Carpenter bees appear remarkably similar to bumblebees but differ slightly in coloration. They are not common, but when infection occurs, the damage can be serious.[2]
Adults of this species tunnel into wood and lay their eggs in individual cells that are supplied with food for growing larvae. Adults emerge and can reinfect the wood. These insects have also been found attacking wood treated with inorganic arsenicals in soil retentions.