Sex Pheromone of Cabbage Aphid Brevicoryne brassicae: Identification and Field Trapping of Male Aphids and Parasitoids

The sex pheromone of the cabbage aphid, Brevicoryne brassicae, is shown by GC and GC-MS analysis of pheromone entrained from sexual females, and by electrophysiological studies on single cell preparations from male antennae, to comprise (4aS,7S,7aR)-nepetalactone. The compound proved to be attractive in a laboratory bioassay and release of the pheromone from glass vials placed above water traps in crops of autumn brassicaceous crops increased the catch of males of this species. The specialist parasitoid of B. brassicae, Diaeretiella rapae, and the more general aphid parasitoid Praon volucre were found in significantly larger numbers in pheromone traps as compared to the controls, under certain conditions.