Oviposition Site Selection of the Codling Moth (Lepidoptera: Tortricidae) and its Consequences for Egg and Neonate Performance.

The codling moth Cydia pomonella (L.) is a worldwide pest of pome fruit. A better understanding of oviposition site selection by this insect would help management of this pest in orchards. Oviposition site selection of codling moth was assessed by manipulative experiments and field survey. In addition, the temperatures of different sites were recorded. Neonate infestation and egg hatching were tested to evaluate the consequences of oviposition site selection. The percentage of eggs laid on the shady side of apple clusters was significantly higher than on the sunny side. How.ever, this was not influenced by leaf surface turning. Percentage of eggs on upper and lower leaf surfaces was significantly influenced by leaf surface turning. Percentage of eggs on the lower leaf surface was significantly higher than turned lower leaf surface (∼41.1% higher) and significantly higher (∼35.5%) on the turned upper leaf surface on than upper leaf surfaces. There was no significant difference in neonate infestation between leaves and fruit, as well as between the upper and lower leaf surfaces. Number of eggs hatching on the shady side of clusters was significantly higher than on the sunny side (56.3% higher). In both the manipulative experiment and field survey, codling moths did not choose the sites with the highest mean temperature, but chose sites suitable for egg development and hatching. This indicates that in the field codling moth, oviposition site selection is not strictly thermophilous, but they look for the lower leaf surface on the shady side, which benefits the offspring.