The impact of codling moth (Lepidoptera: Tortricidae) mating disruption on apple pest management in Yakima Valley, Washington

From 1991 to 1993, pheromone-based mating disruption for control of codling moth, Cydia pomonella (L.)was evaluated in seven apple orchards.Each pheromone-treated orchard was paired with a similar orchard without pheromone.Populations of codling moth, secondary pests, and selected natural controls were monitored.The cost of using pheromone dropped nearly $100 per ha from 1991-1993 because of reductions in the price of dispensers and improved application.Growers saved $87-147 in insecticides per ha in pheromone-treated orchards, because of an 83% reduction in sprays for codling moth, but savings from reduced labor and machinery costs in treated orchards were minimal.Damage from codling moth was high in one treated orchard in 1991 (7.4%), and increased to 20.8% in 1992.The population density of codling moth was low in the other orchards (fruit injury < 0.4%) in all three years.Insecticide applications after petal-fall for secondary pests were reduced by 18% in treated orchards.Populations of secondary pests were similar between orchard pairs.Among natural controls only parasitism of leafminers differed significantly between treated and untreated orchards.In 1991, leafrollers caused > 3% fruit injury in three of seven treated orchards, but were not a problem thereafter.Substituting mating disruption for insecticides to manage codling moth in apple orchards may therefore be successful, but for the first three years, may not substantially improve biological control of secondary pests.