Evaluation of aerosol devices for simultaneous disruption of sex pheromone communication in Cydia pomonella and Grapholita molesta (Lepidoptera: Tortricidae)

Abstract

A two-year study was conducted evaluating PuVer ® aerosol dispensers (Suterra LLC, Bend, OR, USA) for mating disruption of codling moth, Cydia pomonella (L.), and the oriental fruit moth, Grapholita molesta (Busck). The PuVer ® dispenser consists of a pressurized metal canister loaded with pheromone active ingredients dissolved in solvent and housed within a circuit-controlled, plastic dispensing cabinet programmed to release an aerosol spray of pheromone at regular intervals. PuVers ® were deployed at the label-recommended rate of 2.5 ha ¡1 and released ca. 5-10 mg of pheromone (depending on treatment) per 15 min during a 12-h cycle beginning each day at 15:00 h for the duration of the season. In 2005, commercially-managed apple plots (3.2-4.9 ha) were treated with PuVers ® releasing both species' pheromone simultaneously (dual-species) or with twice the number of adjacentlydeployed PuVers ® (4-6 m apart) releasing each individual species' pheromones (single-species), while maintaining comparable overall release rates of pheromone between these two treatments. Plots 100 m away and not treated with pheromone served as the control. Disruption of male C. pomonella and G. molesta orientation to pheromonebaited traps was 46-75 and 91-98%, respectively, in PuVer ® -treated plots compared with untreated controls.There was no statistical diVerence in moth disruption between plots treated with dual-species and single-species PuVers ® . Fruit injury was not statistically diVerent between PuVer ® -treated plots and control plots not receiving pheromone. In 2006, disruption of male moth orientation to traps was 24-26 and 84-97% in PuVer ® -treated plots (2.9-5.7 ha) for C. pomonella and G. molesta, respectively, compared with untreated controls. During this season, fruit injury was lower in pheromone-treated plots compared with untreated controls at mid-season, but not at pre-harvest. Combining the pheromone of both species into single PuVer ® units did not decrease eYcacy of disruption compared with deploying twice as many PuVers ® releasing a similar amount of each individual species' pheromone suggesting that multi-species disruption using PuVers ® is a viable option. However, we conclude that the eYcacy of disruption attained with low-densities (2.5 ha ¡1 ) of PuVers ® at the moth densities recorded in this study is insuYcient for eVective control of C. pomonella without input of companion insecticides.

Mating disruption with low density diffusers for the management of oriental fruit moths (Lepidoptera: Tortricidae) in apple orchards under subtropical climate in southern Brazil

“…These results are contrary to the trend observed by Suckling et al (2007), who showed that mating disruption does not exceed 90% using diffusers at low density. The reduction of the mating interruption index in the last two years may be related to the Oriental fruit moth population increase of almost 25 fold during those years.…”

“…Biolita ® consists of a polypropylene diffuser (9x12 cm) containing 4.10 g of a 90:6:1 mixture of (Z)-8-dodecenyl acetate (89.93%); (E)- Evaluation of the effectiveness of mating disruption. The efficiency of the mating disruption formulation in confusing the chemical communication between male and female oriental fruit moths was calculated by the mating interruption index (MII), MII = (M-P/P)*100, where M is the average number of males captured per trap in mating disruption plots and P is the number of captures in the conventional pesticide plots (STELINSKI et al 2007). The total average number of insects captured per trap in the mating disruption plots, after installation of mating disruption, was compared with that obtained in conventional pesticide plots.…”

“…Therefore, the combination of mating disruption with insecticide is necessary from November to January, in order to reduce early-developing populations as well as the risk of fruit damage by late generations and/or populations that migrate from nearby peach orchards, as noted by II'ichev et al (2003). These issues are most evident in situations with a low-density of diffusers (STELINSKI et al 2007). …”

“…The reduction of the mating interruption index in the last two years may be related to the Oriental fruit moth population increase of almost 25 fold during those years. High pest populations can compromise the efficiency of a protocol for gender confusion, as mentioned by Stelinski et al (2007). In addition, pheromone dispensers can be more easily influenced by wind when using a low rather than high (500 dispensers) density of diffusers.…”

“…The placement of a high density of diffusers causes added labor costs for large orchards. New types of pheromone dispersion technology are being studied (JENKINS 2002;STELINSKI et al 2007) to make the diffusers more affordable and easier to install. Mating disruption for tortricids has several advantages, including pesticide reduction; however, the occurrence of A. fraterculus requires the use of insecticides in apple orchards of subtropical region of Brazil (MONTEIRO et al 2008a).…”