Influence of Canopy Aspect and Height on Codling Moth (Lepidoptera: Tortricidae) Larval Infestation in Apple, and Relationship between Infestation and Fruit Size

Abstract

Monitoring systems based on traps with female attractants are expected to enhance forecasting of insect population size and damage. The optimal placement of such traps should match the small-scale distribution of ovipositing females. In the codling moth, Cydia pomonella (L.) (Lepidoptera: Tortricidae), fruit infestation takes place in proximity to the oviposition site. We characterized the within-tree distribution of codling moth infestations and the size of uninfested fruit based on a survey of 40,000 apples (Malus spp.) from trees belonging to 160 different apple genotypes and growing in two different environments. Each tree was subdivided into 12 sectors, considering canopy aspect (north, east, south, and west) and canopy height (bottom, middle, and top). This study revealed that fruit infestation by the first but not by the second generation of larvae correlated significantly with canopy aspect. Similarly, fruit size differed significantly between the north- and the south-facing tree side for the period of infestation by the first but not by the second larval generation. Significantly lower fruit infestation was observed on the north- compared with the south- or east-facing tree side for the first generation. A significant influence of canopy height on larval infestation was observed in three of eight assessments, in which the middle height level showed the highest infestations. Significant differences in within-tree distribution of codling moth infestation suggest that oviposition preference is guided by nonrandom factors including microclimate, fruit phenology, and wind direction. These cultivar-independent findings should be considered in future monitoring systems that focus on female codling moth.

Effects of ants on arthropod assemblages of a native timber tree in a tropical reforestation plantation

“…), but also indirectly modified if female E. gastralis moths show oviposition preference (Stoeckli et al. ) for trees with lower ant abundance.…”

“…This possibly indicates that E. ruidum can have a protective effect on T. rosea, if it is recruited to trees in sufficiently high numbers. As E. gastralis caterpillars complete their development on the same tree on which oviposition has occurred (Herná ndez and Briceñ o 1999), tree infestation is possibly not only directly affected by ant aggression towards feeding caterpillars (Floren et al 2002), but also indirectly modified if female E. gastralis moths show oviposition preference (Stoeckli et al 2008) for trees with lower ant abundance.…”

Integrated management of tortricid pests of tree fruit

“…The physical structure of tree canopies and entire orchards can have significant effects on the management of pests, including tortricids (Stoeckli et al 2008;Costes et al 2013). Canopy architecture directly impacts spray coverage and the occurrence of refugia within orchards (Xu et al 2006;Duga et al 2015).…”

Body mass and wing geometric morphology of the codling moth (Lepidoptera: Tortricidae) according to sex, location and host plant in the region of Maule, Chile

“…The spatial population dynamics of the codling moth can affect these control strategies in several ways (Mazzi and Dorn, 2012). Landscape, orchard and tree canopy structure influence codling moth dispersal at the local scale and thus its spatial population dynamics (Stoeckli et al, 2008;Ricci et al, 2009Ricci et al, , 2011. The selection of insecticide-resistant individuals in orchards under regular insecticide sprays could be reduced by immigration and gene flow of susceptible individuals from unmanaged areas (Basoalto et al, 2010, Fuentes-Contreras et al, 2014.…”