Electrophysiological analysis of olfactory hair sensilla in male P. pisi has revealed four different types of presumed pheromone receptor cells, maximally responsive to (Z)-11-tetradecenyl acetate (Z11-14:Ac), (Z)-9-tetradecenyl acetate (Z9-14:Ac), (Z)-11-hexadecenyl acetate (Z11-14:Ac) and (Z)-7-dodecenyl acetate (Z7-12: Ac), respectively. These four compounds were tested, singly and in various combinations, for efficacy in attracting P. pisi males in the field. High trap catches were obtained with mixtures of Z11-14: Ac/Z9-14: Ac in the ratio 100/100, whereas the 100/30 and 30/100 mixtures of the two compounds were only slightly attractive. No male P. pisi were captured by single chemicals or binary combinations of Z11-14: Ac/Z11-16: Ac, Z11-14:Ac/Z7-12:Ac, Z9-14:Ac/Z11-16:Ac, Z9-14:Ac/Z7-12:Ac, or Z11-16:Ac/Z7-12:Ac. Various compounds, including Z11-16: Ac and Z7-12:Ac, were tried as third chemicals in addition to 100 μg Z11-14: Ac + 100 μg Z9-14: Ac but none increased trap catches over the basic lure.