Orientation disruption of Planotortrix octo using pheromone or inhibitor blends

Orientation disruption (indicated by reduced trap catch) of adult male Planotortrix octo (Lepidoptera: Tortricidae) was examined in eight small plot trials at four apple orchards over three years, using either (i) Z5-14:OAc (inhibitor), (ii) a blend of 25:75 Z5-14:OAc and Z8-14:OAc (inhibitor plus partial pheromone), or (iii) 50:50 Z8-14:OAc and 14:OAc (pheromone) in polyethylene rope dispensers at 100 or 200 dispensers per 0.1 ha. Use of inhibitor plus partial pheromone gave significant reductions in trap catch in all eight trials. Inhibitor alone gave statistically significant reductions in catch in all three trials where it was tested, but was not as effective as the inhibitor plus partial pheromone in one of these trials. Three trials comparing efficacy between the pheromone and the inhibitor plus partial pheromone blend showed no difference between these blends. Analysis of covariance of trap catch after treatment, using the catch in the first generation in each trap as a covariate, was useful for detection of treatment effects. Traps containing the blend of Z5-14:OAc and Z8-14:OAc were not attractive, suggesting that false trails may not be important where this blend is used, since it is an incomplete pheromone and contains an inhibitor.Disruption of mating was examined in closed containers, with dispensers containing (i), or (ii). Mating frequency was 86.4% in the controls, compared to only 14.3% with the inhibitor present alone, or 1.7% with partial pheromone and inhibitor. The frequency of mating in scotophase within 1–8 h after termination of 24 h exposure to a very high dose of the non-attractive blend of 25%:75% Z5-/Z8-14:OAc was identical for treated and untreated P. octo males.