Optimization of pheromone dispensers for diamondback moth Plutella xylostella

We have investigated the effects of pheromone dispenser design, pheromone release rate, and the products of Z11-16:Ald decomposition on the attractiveness of the pheromone blend (Z)-11-hexadecenyl acetate, (Z)-11-hexadecenal, and (Z)-11-hexadecen-1-ol) in traps to Plutella xylostella males. Rubber minidispensers (K-50) were shown to have an active exposure rime of at least two months and in delta traps to be capable of monitoring a population of P. xylostella throughout the summer in Estonia. Pheromone release rates between 8 and 17 ng/hr are recommended for maximum trap catches. The attractive blend contained 15-35 % of Z11-16:Ac. Decomposition products of Z11-16:Ald inhibited the activity of the pheromone blend when more than 50% of the aldehyde had decomposed.