Wood Beetle (Coleoptera)

Wood-eating Insects

Taxonomy

By wood-eating insects we mean insects that attack wood. Here we can distinguish three categories of species:

• insects found in wood in residential areas
• the insects found in the wood of living trees
• the insects which attack both categories of wood

Indeed, many species found in trees cannot continue to infest homes, such as Scolytidae. On the other hand, there are many species of insects which, although they are found in trees, are often found in houses, but without showing a preference for treated wood, like many Buprestidae.

In general, treated wood insects are classified into three orders: Coleoptera (beetles or “beetles”), Isoptera (termites) and Hymenoptera (wood-eating ants, etc.).

Biology

The biology differs according to the order of the insect. For Coleoptera, the biological cycle is directly linked to the wood, as in most cases both the immature stages and the flourishing ones are found within galleries which they open. The duration of their biological cycle varies depending on the species, from 1 to 10 years. Therefore, early diagnosis also leads to safe treatment. On the contrary, if the number of galleries increases, the fight becomes particularly difficult. The most important families of wood-eating Coleoptera are Anobiidae, Cerambycidae, Lyctidae and Bostrychidae. In the case of the Hymenoptera, which includes various species of wood-eating ants, wasps and bees, wood is used as a “nest” or for laying eggs, while some species of ants (such as Camponotus) open already existing galleries and are favored by high humidity.

Public health

The importance of wood-eaters lies in the destruction of wood in inhabited areas. Consequently, these species are not, in the narrow sense of the term, “Public Health” insects.

Modes of Management

Prevention: For most species, prevention is related to avoiding the use of infested wood but also to various measures that prevent infestation in treated wood (eg repellents, etc.) and entry into the premises.

Monitoring: In general, the detection of insects found in treated wood is particularly difficult and requires knowledge, experience and specialized personnel. It is not an exaggeration to underline that these insects are literally “invisible” since they are not visible themselves, only the infestation they cause or associated symptoms that betray their presence (sawdust for Coleoptera, galleries for termites, etc. a.). Thus, in this case as well, the detection of the attack is done retrospectively, that is, after the appearance of the first symptoms.

Treatment: In general, the treatment of wood-eating insects is very laborious and often leads to failure. The strategies followed differ depending on the type of wood-eating insect. For “bugs” in many cases, gaseous insecticides are used, due to their excellent penetration in places where it is not possible to use other preparations (e.g. liquid insecticides).

Less often, insecticide is “poured” into the galleries. The various wood preservatives do not seem to be effective in all cases. On the contrary, for termites, various insecticides are used which, taking advantage of trophism, can be transmitted from person to person. In this case, the application of insecticide should be done “structurally” and requires special expertise, e.g. inside the walls. Marking the termite nest is the most important step in combating it.

The use of other gases is also a common method.