Advancing codling moth mating disruption: Part 6–comparison of low vs high density approaches

At present, codling moth mating disruption is largely achieved through the manual application of reservoir-type release devices that are typically hand-applied at fairly high densities of 500-1000 units per hectare. To reduce material and labor costs, growers are interested in reducing dispenser density. The approach entails applying many fewer devices, but with each releasing pheromone at a much higher rate than a reservoir dispenser. Over the past few years we have directly compared the performance of high-density, reservoir dispensers to that of two types of low density approaches: an experimental reservoir-type dispenser that is deployed at 50-100 per hectare and aerosol-emitting devices that are deployed at extremely low densities of only one or two per hectare. In field experiments conducted in Michigan, both low emitter density approaches have proved less effective than high density approaches for CM disruption. The best results for CM are consistently achieved when dispensers are distributed uniformly and at a high point source density.