Management of Codling Moth (Lepidoptera: Tortricidae) in Apple with Overhead Watering

The effects of overhead watering on the management of codling moth, Cydiapomonella L., were examined during 1994-1995. Studieswere conducted in small replicated plots of apple, Malus domestica (Borkham), in Yakima, W A. Treatments varied with regard to the timing and length of watering, the amount of water applied, and whether watering was continuous or cycled. Water treatments reduced fruit injury from codling moth by 60-90%versus the untreated control. Moth flight, oviposition, and egg and larval survivorship all were significantly reduced with watering compared with the untreated control in replicated field assays. The major effects of these water treatments on apple trees were the accumulation of mineral deposits and a reduction in fruit size in 1994.Watering only during the evening appeared to minimize these effects. Apple scab, Venturia inaequalis (Cooke), increased during the 2nd yr of this study, but infection levels did not vary among treatments in either year. The potential implementation of overhead watering in apple to improve control of codling moth is discussed.