Author
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Light, Douglas |
Submitted to: Environmental Entomology
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 2/18/2016 Publication Date: 6/29/2016 Citation: Light, D.M. 2016. Control and monitoring of codling moth (Lepidoptera: Tortricidae) in walnut orchards treated with novel high-load, low-density “meso” dispensers of sex pheromone and pear ester. Environmental Entomology. 45(3):700-707 doi: http://dx.doi.org/10.1093/ee/nvw017. Interpretive Summary: Novel low-density per acre “meso” dispensers loaded with both pear ester kairomone and codlemone, the sex pheromone of codling moth, Cydia pomonella (L)., were evaluated versus meso dispensers loaded with pheromone-alone for their mating disruption control in commercial Californian walnut orchards that received no moth-targeted insecticide sprays. Large meso dispensers loaded with high concentrations of codlemone alone (Ph-meso) were applied at rate of 20 per acre and compared with mesos combining codlemone and pear ester (Ph+PE meso) at rates of 10 and 20 per acre. Various commercial pheromone, pear ester (PE), and combined - combo (CM-DA Combo) lures and an experimental codlemone plus dimethyl nonatriene lure were tested alone and as dual-lures with acetic acid (AA) lures for their monitoring ability in untreated orchard plots and plots treated with meso dispensers. Male moth capture in pheromone-baited traps was significantly reduced by 88% in Ph-meso-treated plots and 96% in Ph+PE-meso plots compared with untreated control plots. Similarly, the capture in CM-DA Combo lure traps was significantly reduced for both sexes by 69% in Ph-meso- and 97% in Ph+PE-meso-treated plots. All three meso treatments significantly reduced harvest kernel damage below levels in the untreated control plots for both codling moth-attributed infestation and for the secondary pest, the navel orangeworm, Amyelois transitella (Walker). Moreover, nut injury levels in plots treated with the Ph+PE-meso (at 20 dispensers per acre) were significantly lower than in the Ph-meso plots for both codling moth infestation and combined pest injury. Regression analysis exposed significant predictive effects suggesting that observed nut injury - infestation levels of navel orangeworm were influenced by those levels attributed to codling moth. Monitoring studies demonstrated that greater numbers of codling moths were caught in the untreated control plots and that in all meso plots the most effective kairomone-based lures attracting both sexes were the dual-lures, containing either PE&AA or CM-DA-Combo&AA. The demonstrated disruption and control efficacy of these high-load meso dispensers emitting both sex pheromone and PE and applied at a low-density per acre rate supports further development of the meso dispenser tactic for practical pest management use in walnut orchard with inherent low planting densities. Technical Abstract: Novel low-density per ha “meso” dispensers loaded with both pear ester, ethyl (E,Z)-2,4-decadienoate, kairomone and codlemone, (E,E)-8,10-dodecadien-1-ol, the sex pheromone of codling moth, Cydia pomonella (L)., were evaluated versus meso dispensers loaded with pheromone-alone for their mating disruption control in commercial Californian walnut orchards that received no moth-targeted insecticide sprays. Large meso dispensers loaded with high concentrations of codlemone alone (Ph-meso) were applied at rate of 50 ha-1 and compared with mesos combining codlemone and pear ester (Ph+PE meso) at rates of 25 and 50 ha-1. Various commercial pheromone, pear ester (PE), and combined - combo (CM-DA Combo) lures and an experimental codlemone plus (E)-4,8-dimethyl-1,3,7-nonatriene lure were tested alone and as dual-lures with acetic acid (AA) lures for their monitoring ability in untreated orchard plots and plots treated with meso dispensers.Male moth capture in pheromone-baited traps was significantly reduced by 88% in Ph-meso-treated plots and 96% in Ph+PE-meso plots compared with untreated control plots. Similarly, the capture in CM-DA Combo lure traps was significantly reduced for both sexes by 69% in Ph-meso- and 97% in Ph+PE-meso-treated plots. All three meso treatments significantly reduced harvest kernel damage below levels in the untreated control plots for both codling moth-attributed infestation and for the secondary pest, the navel orangeworm, Amyelois transitella (Walker). Moreover, nut injury levels in plots treated with the Ph+PE-meso (at 50 dispensers ha-1) were significantly lower than in the Ph-meso plots for both codling moth infestation and combined pest injury. Regression analysis exposed significant (R2 = 0.976) predictive effects suggesting that observed nut injury - infestation levels of navel orangeworm were influenced by those levels attributed to codling moth. Monitoring studies demonstrated that greater numbers of codling moths were caught in the untreated control plots and that in all meso plots the most effective kairomone-based lures attracting both sexes were the dual-lures, containing either PE&AA or CM-DA-Combo&AA. The demonstrated disruption and control efficacy of these high-load meso dispensers emitting both sex pheromone and PE and applied at a low-density rate supports further development of the meso dispenser tactic for practical pest management use in walnut orchard with inherent low planting densities. |