The development and regulation of green spruce aphid pest problems in Europe were the subject of a European Community Concerted Action funded in part by the EC Agriculture, Fisheries, Forestry and Agro-Industry Specific Programme as project AIR3- CT94-1883. This Technical Paper is the product of a collaboration between forest research institutes in the four European states that participated in the Concerted Action and a number of other contributors whose work is highly relevant to the project. The Paper provides a comprehensive summary of current knowledge of the green spruce aphid as a pest of spruce and suggests what additional information is required to implement a pest management programme. This publication is no longer available in hardcopy.