Council Directive 78/692/EEC of 25 July 1978 amending Directives 66/400/EEC, 66/401/EEC, 66/402/EEC, 66/403/EEC, 68/193/EEC, 69/208/EEC and 70/458/EEC on the marketing of beet seed, fodder plant seed, cereal seed, seed potatoes, material for the vegetative propagation of the vine, seed of oil and fibre plants and vegetable seed