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 sm all 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:O Ac (inhibitor plus partial pheromone), or (iii) 50:50 Z8-14:OAc and 14 :OAc (pheromone) in polyethylene rope dispensers at 100 or 200 dispens ers per 0.1 ha. Use of inhibitor plus partial pheromone gave significa nt reductions in trap catch in all eight trials. Inhibitor alone gave statistically significant reductions in catch in all three trials wher e it was tested, but was not as effective as the inhibitor plus partia l pheromone in one of these trials. Three trials comparing efficacy be tween the pheromone and the inhibitor plus partial pheromone blend sho wed no difference between these blends. Analysis of covariance of trap catch after treatment, using the catch in the first generation in eac h 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 attract ive, suggesting that false trails may not be important where this blen d is used, since it is an incomplete pheromone and contains an inhibit or. Disruption of mating was examined in closed containers, with dispe nsers containing (i), or (ii). Mating frequency was 86.4% in the contr ols, compared to only 14.3% with the inhibitor present alone, or 1.7% with partial pheromone and inhibitor. The frequency of mating in scoto phase within 1-8 h after termination of 24 h exposure to a very high d ose of the non-attractive blend of 25%:75% Z5-/Z8-14:OAc was identical for treated and untreated P. octo males.