This document specifies a method for the determination of the preventive action of a wood preservative against the Reticulitermes species of European termites1 when the preservative is applied as a surface treatment to wood. This method is applicable to: water-insoluble chemicals which are being studied as active ingredients; organic formulations, as supplied or as prepared in the laboratory by dilution of concentrates; organic water-dispersible formulations as supplied or as prepared in the laboratory by dilution of concentrates; and water-soluble materials, for example salts. NOTE This method can be used in conjunction with an ageing procedure, for example EN 73 or EN 84.