Control of the Beet Armyworm, Spodoptera Exigua (hübner), with Synthetic Sex Pheromone

The feasibility of synthetic sex pheromone as a communication disruption agent for the control of the beet armyworm, Spodoptera exigua (Hübner), was examined by dispensing a 7:3 mixture of (Z,E)-9, 12-tetradecadienyl acetate and (Z)-9-tetradecen-1-o1. When this mixture was dispensed into a 155 ha field, the attraction of male moths to sex pheromone traps was completely inhibited, while the density of egg masses was reduced to 6%, and that of young larvae was reduced to 1%, relative to densities in an untreated field about 9 km away. Follow-up studies showed that the rate of mating inhibition in the treated field was C. 97%. When the mixture was dispersed into greenhouses covering .07 to .13 ha, the larval density was drastically reduced within 1 month. In the untreated greenhouse, larval density increased to about 9 times the initial density. Treatment with 500 dispensers in a .02 ha greenhouse reduced the estimated mating rate of females to 20-50%, whereas the mating rate was 95% without treatment. When sex pheromone treatment was combined with a light trap, the mating rate was reduced to 2-3%. These results show that the pheromone treatment gives effective control of beet armyworm population densities in both the open field and greenhouse.