Which substance is commonly used to protect wood from insect damage?

Borates are commonly used to protect wood from insect damage due to their effectiveness as both a fungicide and insecticide. They work by disrupting the digestive systems of insects that consume wood, making it unappetizing or harmful to them. Additionally, borates help to inhibit the growth of mold and decay fungi, which can further compromise the integrity of wooden structures. This dual protective action against both pests and degradation makes borates a popular choice in wood preservation processes.

Acids and alkalis, while they can affect the overall properties of wood or certain pests, do not specifically target insect protection and are not commonly used for this purpose. Mineral oils, on the other hand, may provide a barrier against moisture or some pests but lack the chemical efficacy that borates possess for long-term protection against wood-destroying insects.