Attractant Activity of the Female Sex Pheromone of Diamondback Moth, Plutella xylostella (L.), and Analogue

Abstract

Attractant activity of the female sex pheromone components of diamondback moth, (Z)-11-hexadecenal and (Z)-11-hexadecenyl acetate, has been preliminarily reported, and recently their analogue, (Z)-11-hexadecenol, has been shown to exert a synergistic effect on the pheromonal activity of the two components. Therefore, attractant activity of mixtures of these chemicals loaded on rubber septa was extensively tested using sticky traps in the cabbage fields. The mixture of (Z)-11-hexadecenal and (Z)-11-hexadecenyl acetate attracted mostly males in the ratio of 5:5 at 0.01 to 0.1mg levels in the spring and summer except mid-summer and at 0.1 to 1mg levels in the winter, respectively. The pheromonal activity of a mixture of (Z)-11-hexadecenal and (Z)-11-hexadecenyl acetate in the mid-summer was further enhanced by adding 1 to 10% of (Z)-11-hexadecenol, On the other hand, the pheromonal activity in the winter was poorly enhanced only by addition of 1% of (Z)-11-hexa-decenol. The mixture of (Z)-11-hexadecenal and (Z)-11-hexadecenyl acetate in the ratio of 5:5 at 0.1mg level with additional 1% of (Z)-11-hexadecenol showed fairly stronger activity than that of five virgin females in almost all seasons. The pheromonal activity remained strong at least for some 40 days even in the summer. It is concluded that traps baited with the mixture of (Z)-11-hexadecenal, (Z)-11-hexadecenyl acetate and (Z)-11-hexadecenol in the ratio of 5:5:0.1 at 0.1mg level loaded on rubber septa can be used effectively as a monitoring system for the diamondback moth.