DEVELOPING MATING DISRUPTION OF OBLIQUEBANDED LEAFROLLER (LEPIDOPTERA, TORTRICIDAE) IN WASHINGTON-STATE

Field studies were conducted from 1992 to 1996 to select the most effe ctive sex pheromone blend for mating disruption of the obliquebanded l eafroller, Choristoneura rosaceana (Harris), in tree fruit orchards in Washington. Dispensers loaded with a e-component pheromone blend, (Z) -11-tetradecen-1-yl (Z11-14:OAc) and (E)-11-tetradecen-1-yl (E11-14:OA c), a 3-component blend that included the addition of (Z)-11-tetradece nal (Z11-14:Ald), and a I-component blend also including (Z)-11-tetrad ecen-1-ol (Z11-14:OH) were compared within 0.1-ha orchard plots and 10 0-m(2) field cages. The addition of Z11-14:Ald to the 2 acetate compon ents with or without Z11-14:OH did not improve mating or disruption of communication. No disruption occurred in field cages treated with E11 -14:OAc alone or an 88:12 (%) E:Z 11-14:OAc blend. Management of C. ro saceana with mating disruption was evaluated for 2 yr in three 16-ha a pple orchards by using a 94:6% Z:E11-14:OAc blend. Orchards were treat ed with 1,000 polyethylene tube dispensers per hectare emitting approx imate to 0.9 mg of pheromone per day. Populations were also monitored in 3 similar 8-ha orchards treated only with insecticides. Catches of male moths in traps baited with synthetic lures and virgin females wer e significantly lower (92-99%) in pheromone-treated than in untreated orchards. Larval population densities and fruit injury did not differ between treatments. No significant differences were found in larval po pulation densities, trap catch, or fruit injury between the 2-ha cente r and the outer 14-ha areas of the pheromone-treated orchards. Signifi cant increases in catch by lure-baited traps and fruit injury occurred in the pheromone-treated orchards from the Ist to 2nd yr of the study . The pheromone treatment saved approximate to$250/ha in insecticide c osts over 2 yr. arval population densities, trap catch, or fruit injur y between the 2-ha center and the outer 14-ha areas of the pheromone-t reated orchards. Significant increases in catch by lure-baited traps a nd fruit injury occurred in the pheromone-treated orchards from the Is t to 2nd yr of the study. The pheromone treatment saved approximate to $250/ha in insecticide costs over 2 yr.