TRIFLUOROMETHYL KETONES AS INHIBITORS OF THE PROCESSIONARY MOTH SEX-PHEROMONE

Aliphatic and aromatic trifluoromethyl ketones have been evaluated in the laboratory and in the field as inhibitors of the pheromone respons e of the processionary moth Thaumetopoea pityocampa males. Among them, two compounds, (Z)-1,1,1-trifluoro-15-octadecen-13-yn-2-one and (Z)-1 ,1,1-trifluoro-16-nonadecen-14-yn-2-one, are closely related analogs o f the natural pheromone (Z)-13-hexadecen-11-ynyl acetate. In the labor atory experiments, carried out by pre-exposure of males to vapors of t he chemicals, or-naphthyl trifluoromethyl ketone, beta-naphthyl triflu oromethyl ketone, 1,1,1-trifluorotetradecan-2-one and (Z)-16-nonadecen -14-yn-2-one displayed notable blockage of the pheromone detection on EAG. The activity of 1,1,1-trifluorotetradecan-2-one is postulated to be due to the inhibition of the pheromone-degrading esterase. In gener al, the compounds have shown low specificity for the substrate and exh ibited only a modest or null EAG intrinsic activity. In the field, ben zyl trifluoromethyl ketone, trifluoroacetophenone, (Z)-1,1,1-trifluoro -15-ociadecen-13-yn-2-one, (Z)-1,1,1-trifluoro-16-nonadecen-14-yn-2-on e and beta-naphthyl trifluoroacetate showed a remarkable disruptant ef fect when mixed with the pheromone in 1:0.1, 1:1 and 1:10 ratio. (Z)-1 6-Nonadecen-14-yn-2-one has been found to be a modest agonist of the n atural pheromone, exhibiting an attractant activity threefold lower th an the parent molecule.