Evaluation of novel semiochemical dispensers simultaneously releasing pear ester and sex pheromone for mating disruption of codling moth (Lepidoptera: Tortricidae)

The performance of polyvinyl chloride polymer (PVC) dispensers loaded with two rates of ethyl (E,Z)-2,4-decadienoate (pear ester) plus the sex pheromone, (E,E)-8,10-dodecadien-1-ol (codlemone) of codling moth, Cydia pomonella (L.), was compared with similar dispensers and two commercial dispensers (Isomate (R) and CheckMate (R)) loaded only with codlemone. Dispenser evaluations were conducted in replicated small (0.1 ha) and large (2 ha) field trials in apple, Malus domestica (Borkhausen), during 2006 (Washington) and 2007 (Michigan, large plot study only). Data recorded included male captures in traps baited with virgin female moths and codlemone lures and direct observations of moth behaviour in treated plots. Volatile air collections of field-aged dispensers were conducted under laboratory conditions. Disruption of male catch in codlemone-baited traps was generally similar among dispenser treatments, except for two instances: lower moth catches with the single and dual-component PVC dispensers, compared with Isomate (R), during the first flight in the large plots in Michigan in 2007 and for the dual-component PVC dispenser compared with the CheckMate (R) dispenser during the second flight in small plots in Washington in 2006. Levels of fruit injury were similar in large plots treated with all dispensers. Male moth catches in virgin female-baited traps did not differ among dispenser treatments and were significantly lower than the untreated control. Behavioural observations of adult moths in the field verified anemotactic approaches within 20 cm of pheromone dispensers loaded with and without pear ester that lasted ca. 15 s on average. Field-aged dual-component dispensers released pear ester at a >5-fold higher rate than codlemone over the first 8 weeks and this ratio declined to near unity by 18 weeks.