CHEMICAL AND BEHAVIORAL EVIDENCE FOR A 3RD PHEROMONE COMPONENT IN A NORTH-AMERICAN POPULATION OF THE BLACK CUTWORM MOTH, AGROTIS-IPSILON

The sex pheromone of Agrotis ipsilon had been previously identified as a blend of (Z)-7-dodecenyl acetate (Z7-12:Ac) and (Z)-9-tetradecenyl acetate (Z9-14:Ac). A synthetic blend of Z7-12:Ac and Z9-14:Ac (30 mu g: 10 mu g) is effective in attracting males in the field. In several countries, addition of (Z)-11-hexadecenyl acetate (Z11-16:Ac) to the p reviously identified blend increases male captures, but this had not b een demonstrated in North America. We found Z11-16:Ac, in addition to Z7-12:Ac add Z9-14:Ac, from pheromone gland extracts of females from N orth America. The mean ratio of Z7-12:Ac, Z9-14:Ac, and Z11-16:Ac prod uced by individual females was 70.5:14.2:15.3, respectively. In Kentuc ky, addition of Z11-16:Ac (60 mu g) to a two-component blend of Z7-12: Ac and Z9-14:Ac significantly increased the trap capture rate in the f ield. Traps baited with this three-component blend were 3.3 times (199 5) and 4.6 times (1996) more effective in capturing male A. ipsilon th an the two-component blend. This improved effectiveness resulted in de tection of A. ipsilon in 60% more of the sampling periods in the two y ears. In the wind tunnel, males flew upwind and contacted a rubber sep tum loaded with a three-component blend including Z11-16:Ac significan tly more frequently than they did to any two-component blend. These re sults demonstrate that Z11-16:Ac is a pheromone component in this Nort h American population of A. ipsilon.