Changes to Council Directive of 15 July 1991 concerning the placing of plant protection products on the market (91/414/EEC)
EU Directive 1991/414
Made by Council Directive 2004/66/EC of 26 April 2004 adapting Directives 1999/45/EC, 2002/83/EC, 2003/37/EC and 2003/59/EC of the European Parliament and of the Council and Council Directives 77/388/EEC, 91/414/EEC, 96/26/EC, 2003/48/EC and 2003/49/EC, in the fields of free movement of goods, freedom to provide services, agriculture, transport policy and taxation, by reason of the accession of the Czech Republic, Estonia, Cyprus, Latvia, Lithuania, Hungary, Malta, Poland, Slovenia and Slovakia
From legislation.gov.uk's record of changes, the official one: see it there.