Females of the aphid parasitoid Praon volucre were attracted to lures containing synthetic aphid sex pheromone components, particularly (+)-(4aS,7S,7aR)-nepetalactone, when these were placed on water traps in cereal fields in autumn. Trap catches were greatest at a site in S.W.England and fewest at sites in northern England and northern Germany, presumably due to climatic differences. Responses to the pheromones were not detected for any other cereal aphid parasitoids in the field trials, although Aphidius rhopalosiphi appears to possess olfactory receptors for (+)-(4aS,7S,7aR)-nepetalactone. A potential strategy for the use of aphid sex pheromone lures to manipulate aphid parasitoids in the field, in order to enhance their impact on aphid populations, is outlined. none