Which type of wood surface allows liquid insecticides to penetrate more effectively?

A rough wood surface allows liquid insecticides to penetrate more effectively because the texture increases the surface area that the insecticide can interact with. The irregularities and small crevices in a rough surface enable the insecticide to settle into the wood more easily, enhancing absorption.

In contrast, smooth and polished surfaces may create a barrier that can hinder penetration, as they have fewer depressions for the liquid to enter. Painted surfaces also impede the penetration of insecticides since the paint acts as a protective layer, preventing direct contact with the untreated wood beneath. Therefore, a rough texture is optimal for the effectiveness of liquid insecticides in treating wood-destroying pests.