A new four-component sex pheromone blend for light brown apple moth (Epiphyas postvittana) was examined for efficacy of communication disruption in laboratory and field trials. Vineyard trials using SPLAT LBAM! examined disruption of traps in the presence of: a) the current two-component ((E)-11- tetradecenyl acetate and (E,E)-9,11-tetradecadienyl acetate, 95:5), b) a new four-component blend ((E)- 11-tetradecenyl acetate and (E,E)-9,11-tetradecadienyl acetate plus (E)-11-tetradecen-1-ol and (E)-11- hexadecenyl acetate (10:0.5:0.1:0.05)), c) higher ratio of the two new compounds (10:0.5:10:10), d) four compounds with an antagonist ((Z)-11-tetradecenyl acetate) added, e) three compounds with antagonist minus the most expensive component ((E,E)-9,11-tetradecadienyl acetate), compared to f) untreated controls. In the laboratory, 69.0% of untreated pairs mated, and communication was sup- pressed by both attractive blends (41.1% communication (P 1⁄4 0.024, two-component blend), and 18.4% communication (P 1⁄4 0.003, four-component blend)). In vineyards, totals of 24,776 and 41,053 male moths were caught in the two trials, respectively, to delta traps baited with four-component lures and virgin females. Communication disruption was achieved at a higher level with a four-component blend for 13/14 weeks in disruption trial one and for 10/10 weeks in disruption trial two, compared with the two-component blend. Disruption was on average improved by 12% with the four-component blend compared to the two-component blend (P 1⁄4 0.091). Other blends were less effective at communication disruption. The best formulation released from SPLAT! was only weakly attractive compared to rubber septa, so false trail following to point sources was unlikely to be as important as other mechanisms.