Characterization of microencapsulated pear ester, (2E,4Z)-ethyl-2,4-decadienoate, a kairomonal spray adjuvant against neonate codling moth larvae.

Codling moth (CM), Cydia pomonella (Lepidoptera: Tortricidae), is the key pest of apples, pears, and walnuts worldwide. The pear-derived kairomone, ethyl (2E,4Z)-2,4-decadienoate, the pear ester (PE), evokes attraction and arrestment of CM larvae. Microencapsulated PE formulation (PE-MEC) enhances the control efficacy of insecticides when used as a spray adjuvant. Characterization of the microencapsulated kairomone, including microcapsule size, concentrations, emission rates, and larval response, was performed. Microcapsule diameter ranged from 2 to 14 mum, with 68% of capsules being 2-3 mum, and the concentration of microcapsules averaged 25.9 x 10(4) capsules per mL of field spray solution. Headspace collections showed emission of PE was related to PE-MEC concentration and was best described as first-order power decay. Neonate larvae responded to PE-MEC applications aged through 14 days. These results demonstrated that application of PE-MEC concurrent with insecticides may increase neonate foliar wandering, thereby disrupting host location and enhancing mortality by prolonging its exposure to insecticide.