The Regulation lays down implementing rules as to the fourth stage of the programme of work referred to in article 8(2) of Directive 91/414/EEC, which concerns the marketing of plant protection products. The initial implementation of this fourth stage concerns the notification of the active substances referred to in Annexes I and II to this Regulation with a view to their possible inclusion in a subsequent priority list of active substances with a view to their possible inclusion in Annex I to t