Extreme temperatures (heat and cold)
Woodworms are sensitive to temperature, which can be exploited in the fight against them.
Heat is a very effective remedy:
Woodworm larvae die at temperatures above 55°C. Smaller items can therefore be placed in the oven at 60°C for about an hour. Larger objects can be placed in a sauna for a few hours or in a black plastic bag in the blazing summer sun.
Important: Allow the wood to cool slowly afterwards to prevent cracking.
Advantages: Heat reliably kills all stages of the woodworm (larvae and beetles).
Disadvantage: Not all furniture fits in the oven, and not everyone has a sauna at their disposal. In addition, very damp wood must not be heated quickly, as this can cause it to crack.
Cold also helps:
At temperatures below approximately -10°C, woodworms become sluggish and die if frozen for a long time. Smaller wooden objects can be placed in the freezer (at least -18°C) for several days. Large pieces of furniture can be placed outside in dry weather in winter when temperatures remain below -10°C for several days.
Advantage: Cold treatment is gentler on the wood than heat and is also chemical-free.
Disadvantage: You need very low temperatures over a long period of time – a normal freezer is often only sufficient for small items, and it does not always freeze reliably outside for days on end. In addition, the objects must be dry so that frost does not cause moisture damage to the wood.
Evaluation: Heat and cold are extremely effective methods of killing woodworms without chemicals. They are particularly suitable if individual pieces are infested (e.g., a chair, a small shelf) and you have the option of placing them in an oven, sauna, freezer, or extreme weather conditions. However, there are limits to this method for permanently installed or very large wooden parts—no one can put their roof beams in the freezer. In such cases, the following methods come into play.
Sources:
https://www.selbst.de/holzwurm-holzwuermer-erkennen-und-bekaempfen-45690.html
https://www.haus.de/leben/holzwurm-bekaempfen-diese-hausmittel-helfen-24241