Inhibition of the processionary moth sex pheromone by some haloacetate analogues

Several haloacetate analogues of (Z)‐13‐hexadecen‐ll ‐ynyl acetate, the main component of the sex pheromone of the pine processionary moth Thaumetopoea pityocampa, have been found to be good inhibitors of the natural pheromone. In field tests, the fluorinated compounds exhibited higher antipheromone activity than the corresponding chlorinated analogues, the order of activity being monofluoro > difluoro > trifluoro > monochloro > dichloro > trichloroacetate. In EAG bioassays the trifluoroacetate analogue showed the highest inhibition effect among all the compounds tested. These results agree with others previously reported, and show the primary role played by the steric size of the halogen in these analogues in order to achieve a notable inhibition of the pheromone action.