Behavior of codling moth (Lepidoptera: Tortricidae) neonate larvae on surfaces treated with microencapsulated pear ester.

Codling moth, Cydia pomonella (L.), larvae cause severe internal feeding damage to apples, pears, and walnuts worldwide. Research has demonstrated that codling moth neonate first instar larvae are attracted to a pear-derived kairomone, ethyl (2E,4Z)-2,4-decadienoate, the pear ester (PE). Reported here are the behavioral activities of neonate codling moth larvae to microencapsulated pear ester (MEC-PE) applied in aqueous solutions to both filter paper and apple leaf surfaces that were evaluated over a period of up to 20 d of aging. In dual-choice tests the MEC-PE treatment elicited attraction to and longer time spent on treated zones of filter papers relative to water-treated control zones for up to 14 d of aging. A higher concentration of MEC-PE caused no preferential response to the treated zone for the first 5 d of aging followed by significant responses through day 20 of aging, suggesting sensory adaptation as an initial concentration factor. Estimated emission levels of PE from treated filter papers were experimentally calculated for the observed behavioral thresholds evident over the aging period. When applied to apple leaves, MEC-PE changed neonate walking behavior by eliciting more frequent and longer time periods of arrestment and affected their ability to find the leaf base and stem or petiole. Effects of MEC-PE on extended walking time and arrestment by codling moth larvae would increase temporal and spatial exposure of neonates while on leaves; thereby potentially disrupting fruit or nut finding and enhancing mortality by increasing the exposure to insecticides, predation, and abiotic factors.