COMMUNICATION DISRUPTION FOR CONTROL OF THE BEET ARMYWORM, SPODOPTERA-EXIGUA (HUBNER), WITH SYNTHETIC SEX-PHEROMONE

The feasibility of synthetic sex pheromone as a communication disruption agent for the control of the beet armyworm, Spodoptera exigua (Hubner), was examined by dispensing a 7:3 mixture of(Z,E)-9,12-tetradecadienyl acetate and (Z)-9-tetradecen-1-ol. When the pheromone was dispersed into a 155 ha field, attraction of male moths to sex pheromone traps was completely inhibited and densities of egg masses and young larvae were reduced to 6% and 1%, respectively, relative to those in an untreated field about 9 km away. Follow-up studies enabled to estimate that the rate of mating inhibition in the treated field was ca. 97%. When the pheromone was dispersed into 0.07-0.13 ha greenhouses, the larval density was drastically reduced within 1 month, while the density increased to about 9 times of the initial density in the untreated greenhouse. Treatment with 500 dispensers in a 0.02 ha greenhouse reduced the estimated mating ratio in females to 20-50%, whereas mating rate was 95% without treatment. When sex pheromone treatment was combined with the use of light trap, the mating rate was reduced to 2-3%. These results indicated the efficacy of synthetic sex pheromone in controlling S. exigua population both in open fields and in greenhouses.