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, ororganic water dispersible formulations, as supplied or as prepared in the laboratory by dilution of concentrates,orwater soluble products, for example, salts.NOTEAn ageing procedure cannot be combined with this method.