This document specifies a method for the determination of the eradicant action of a surface application of a fast and a slow acting wood preservative product or a deferred acting wood preservative product on timber infested with larvae of Hylotrupes bajulus (Linnaeus). This method is applicable to: ?? organic formulations@ as supplied or as prepared in the laboratory by dilution of concentrates; or ?? organic water-dispersible formulations@ as supplied or as prepared in the laboratory by dilution of concentrates; or ?? water-soluble products@ for example@ salts. NOTE An ageing procedure cannot be combined with this method.