Nacerdes malamura is the scientific name for the woodworm.
Yellowish brown, with black dots on the elytra (coreaceous wings).
It has 3 stripes along the entire length of the elytra.
Eggs are laid in damp, decaying wood.
Larvae bore into the wood for about 9 months and then emerge in summer.
The larvae require the wood to be constantly wet so that the fungi break down the wood fibres.
There are two main sources of infestation in buildings – wet structural timbers due to infiltration by rainwater, and wooden parts under reinforced concrete foundations, paths and footpaths.
It should not be forgotten that, historically, wood is the most versatile active material used by man, playing a key role in the development of civilisations: weapons and tools, boats and land transportation, musical instruments and buildings, furniture and paper are some of its many uses. Thus, any human construction, with a relevant patrimonial or artistic nature, may be destroyed or significantly damaged by woodworm.
The large woodworm (hilotrupes bajulus, L.) is one of the most important xylophages in some southern European countries, including Portugal. In buildings it is often located on the wooden structure of the roof, a location favoured by the microclimate existing there.
The most representative small woodworm in Portugal are: Anobium punctatum, De Geer and Lictus sp. Anobium punctatum is a species of woodworm of great economic value that attacks the building’s wood. The preference of the anobium for old wood explains why the holes made by its larvae are accepted as evidence of the age of the wood; it is rare, in fact, for wood to be attacked by the anobium before 20 years after its cutting. The larvae of the Lichthyidae family, similarly to the Anobidae, feed on wood: Lictus brunneus and Lictus Fabricius are the most representative woodworm of this family.
Limiting our action to the two basic uses of wood – buildings and furniture – it must be clearly understood that wood deteriorates not only with age; woodworm plays a major role in the deterioration of wood used in these two contexts. It is a disadvantage for the owner of a space affected by this pest that the large woodworm often becomes detectable only after it has already caused serious damage to the wood. For this reason, the degree of infestation of a roof, for example, should always be determined by an expert, since some beams may have to be replaced or reinforced due to the decreased resistance caused by the galleries opened by the larvae of the insect.
As the destroying action of these insects can be avoided, the wood preventive and curative treatments are vital. Gas fumigation and immersion in adequate insecticide solutes are examples of the techniques to be used.