Following the first survey of intraspecific pheromone variability in Ostrinia nubilalis Hbn (ECB) in Europe and North America (K LUN & C OOPERATORS , 1975), the sex attraction responses of male populations of ECB to 3 ratios of the Z : E isomers (97 : 3 , 35 : 65 , 3 : 97) of the 11-tetradecenyl acetate were studied at 28 locations in Europe, 3 in Egypt and one in the Hebei province of the People's Republic of China, during the 1978-1981 period, as a part of the cooperative program of I.W.G.O. (International Working Group on Ostrinia). In the palearctic region, the ECB populations exhibited pheromone polymorphism. The Z phenotype was the only one observed in 13 localities, mainly with low levels of capture. In other places, the two phenotypes Z and E were in sympatry, very often with the presence of their presumed hybrid Z x E, responding to the 35 : 65 Z : E mixture. The survey confirms the great prevalence of the Z phenotype in corn fields all over the world. The E phenotype was prevalent only in 5 locations in northern Italy and southern Switzerland.