Preventive measures against woodworms
The best thing to do is to prevent woodworm from getting into the wood in the first place! A few preventive measures can significantly reduce the risk of infestation:
Keep wood dry: Woodworms thrive in damp environments and need wood moisture levels above ~10% to survive. Therefore, ensure a dry indoor climate, especially in basements and attics. Adequate heating and ventilation removes moisture from the wood – if the wood falls below a residual moisture content of 8–10%, any larvae present will die and new beetles will avoid it.
Treat wood preventively: For particularly vulnerable woods (e.g. roof beams made of softwood), it is worth applying a preventive wood protection coating. Special preparations are available in stores that can be applied to form a protective film against insects. Mamba woodworm killer can also be used prophylactically – it protects the wood from new infestation in the long term, as permethrin also has a deterrent effect on wood-destroying insects.
Use impregnated wood: When building new or renovating, pressure-impregnated wood or material that has already been treated with wood preservative should be used in critical areas (roof truss, exterior half-timbering) wherever possible. Many types of construction timber are now treated against insects and fungi at the factory. This deters woodworms and house longhorn beetles.
Seal surfaces: Larvae of wood-boring beetles prefer to lay their eggs in rough, untreated wood surfaces. Smoothly varnished or glazed wood is less attractive. An intact varnish or wax surface can therefore make it more difficult for woodworms to penetrate – it is not 100% protection, but it helps.
Check regularly: Whether it's furniture in the basement or beams in the roof, check for signs of woodworm once or twice a year (see next article on identification features). If detected early, an infestation is much easier to contain. If you discover drill holes or wood dust, you can test for woodworm by placing some adhesive tape or wax over the suspicious holes. If the markings remain intact for several weeks, there is probably no longer any active woodworm inside. If in doubt, seek professional advice before major damage occurs.
Sources:
https://www.immobilien-und-hausbau.de/rund-ums-haus/heimwerken/holzwurmer-bekaempfen/
https://www.haus.de/leben/holzwurm-bekaempfen-diese-hausmittel-helfen-24241
https://hausundgrund-neukoelln.de/holzwurm-oder-hausbock-erkennen-und-dagegen-vorgehen
https://www.selbst.de/holzwurm-holzwuermer-erkennen-und-bekaempfen-45690.html