There are various methods to fight against woodworm. This article analyzes the advantages and disadvantages of the different systems, from the most traditional to the most innovative.
The most common anti-woodworm treatments are the following:
- Traditional method
- Method with toxic gases
- Anoxia method
- Microwave treatment
- ASIP system for ayous wood
Traditional systems, such as the application of an anti-woodworm product with brushes or syringes into the holes do not solve the problem.
The insertion of the product in the holes, in fact, does not allow to penetrate inside for more than a few millimeters.
Therefore it is not possible to reach the larvae and the eggs which, in the meantime, will continue to develop, giving rise to a new cycle of infestation.
Until a few years ago, the only effective way to fight against woodworms was the use of gaseous substances with an insecticidal effect: ethylene oxide, methyl bromide, potassium cyanide.
The mouldings were transported outside the inhabited centers, treated with toxic gases and then returned to the place of origin where, for a long time, they released the substances they were impregnated with.
All fumigations with toxic gases have four aspects in common:
• They are effective towards insects.
• They are extremely dangerous for human health (they cause tumors, leukemia, genetic mutations, alterations of the neuro-endocrine system).
• They react chemically with the mouldings determining structural and chromatic alterations (in other words, they produce further degradation).
• They are very expensive.
Since the end of the 1990s an ecological alternative to insecticide gases became available: the anoxia method, which consists in eliminating the parasites simply by keeping the mouldings in conditions of absence of oxygen for a few weeks.
The air that we all breathe is a mixture of gas: nitrogen (78%), oxygen (21%), argon (1%) and in small percentages: neon, helium, methane. Oxygen is the only one of these gases that allows survival: by reducing its presence to negligible values, lethal conditions are obtained for all the parasites at each stage of their life cycle: adult, egg, larva and chrysalis.
Contrary to what one might think, what determines the death of insects in absence of oxygen is not the suffocation but the loss of water. The mechanism of parasite respiration, in fact, is very particular: they breathe air with extremely low frequency through a series of openings. If the amount of oxygen in the air is reduced, the rate of their breathing increases very much (up to ten times the normal one) thus leading to death by dehydration.
The system consists essentially in replacing the oxygen with the nitrogen inside the waterproof enclosures in which the mouldings have been previously inserted.
The duration of this operation can vary from a few hours to a few days.
Once the oxygen has been eliminated, the mouldings are left inside the wrapper for at least three weeks: period that guarantees the total elimination of any type of insect.
The currently safest and most definitive method for eliminating woodworms from furniture and mouldings is that of microwaves. It is a method that has become an operational reality after twenty years of research.
The mouldings are placed inside a microwave oven.
The microwaves are used to raise the temperature of the aqueous substances that are inside the oven. When they come into contact with water molecules, microwaves increase their motion, with a consequent increase in temperature.
Mouldings contain minimal percentages of water, so they are not heated by microwaves. On the contrary, the woodworms are largely made up of water, so microwaves are an excellent way to heat them up to lethal temperature (which is 55 degrees Celsius), without damaging the mouldings.
Each of us has directly experienced that, by taking the dish from the microwave oven after treatment, the oven environment remained cold. All the electromagnetic energy injected was transformed into the heat that heated the food. Similarly, timber subjected to electromagnetic fields heats up starting from the innermost part so as to reach the eggs and larvae of woodworms that are in the center of the wood.
Moreover, the microwave treatment is characterized by the speed and the possibility of handling the moulding immediately after disinfection.
The anti-worm treatment with microwaves is now routinely used by several companies specialized in the restoration and conservation of works of art.
It is possible to buy the ayous wood already treated with the ASIP anti-woodworm system.
This treatment consists in the application of boron salts to the wood. The basic characteristic of the treatment consists in modifying the taste of wood in such a way that wood-worms do not like it. It therefore guarantees protection against woodworms for an indefinite future time. But if the worms or larvae are already inside the wood they could continue their work of devastation.
The application of boron salts can be carried out by brushing the wood with a liquid in which the salts are dissolved, trying to penetrate the wood as much as possible. A more pervasive treatment consists of immersing the wood in the liquid that contains the salts and keeping it immersed for a certain time. If a certain pressure is exerted on the liquid, the effect of penetrating the liquid into the wood is obtained to reach even the insects and larvae that are in the center.
However, we have to consider that with this treatment the wood gets wet and then dried. All of this could have some consequences in its stability.