Simultaneous disruption of pheromone communication and mating in Cydia pomonella, Choristoneura rosaceana and Pandemis limitata Lepidoptera:Tortricidae) using Isomate-CM/LR in apple orchards

Abstract

Simultaneous disruption of pheromone communication and mating of codling moth, Cydia pomonella (L), and four leafroller (Lepidoptera:Tortricidae) species, Choristoneura rosaceana (Harris), Pandemis limitata (Robinson), Archips rosanus (L.) and Archips argyrospilus (Walker ) using an incomplete mixture of their individual pheromone components was studied in organic apple orchards, in Cawston, BC, 1997. Multi-species disruption with a single 500 'rope' dispenser / ha application of Isomate-CM/LR was compared to a single 500 dispenser / ha application of Isomate-C. Season-long disruption was assessed using synthetic pheromone traps and laboratory-reared females in mating tables. Mean seasonal recaptures of sterile male C. pomonella, using 10 mg codlemone lures in orchards receiving releases of 1000 males / ha / week, were not significantly different in half-orchard plots (0.5 - 1 ha) of Isomate-CM/LR or Isomate-C. Mating of C. pomonella in Isomate-C- and Isomate-CM/LR-treated plots was negligible. Isomate-CM/LR significantly reduced catches of C. rosaceana and P. limitata relative to catches in Isomate-C-treated plots. Few A. rosanus and no A. argyrospilus were caught in any orchard. Mating of C. rosaceana and P. limitata in Isomate-CM/LR treated plots was significantly less than in Isomate-C-treated plots. Our results indicate Isomate-CM/LR will disrupt mating of C. pomonella equivalent to Isomate-C and may provide sufficient disruption of leafrollers to supplement biological control in organic orchards. Further studies are needed to show impacts of mating disruption on leafroller populations and damage when applied to larger areas and for several seasons sequentially