Plant defense to herbivore: role of leaf epicuticular wax composition of citrus cultivars in citrus leafminer, Phyllocnistis citrella Stainton (Lepidoptera: Gracillariidae) larval density.

Aiming to assess the role of leaf waxy cuticle and its chemical composition on citrus leafminer, Phyllocnistis citrella (Lepidoptera: Gracillariidae) larval feeding, six citrus cultivars were selected. Our findings showed that the larval density was higher at 59.5% on Mayer lime followed by 53.6% on Kinnow and the least activity of CLM was found (19.3-38.4%) on Musambi. The cuticular wax layer was found greater (67.6 µg/cm2) in Tangerine (Fairchild) followed by 59.6 µg/cm2 in Succari and 56.0 µg/cm2 in Musambi. The results showed that the epicuticular wax layer had negative and significant (P < 0.05) relation with the larval density. Other chemical compounds; aldehyde, alcohol, fatty acid, and hydrocarbon showed non-significant relation with the CLM larval density. Multiple regression analysis showed a 33.5% role of epicuticular wax with CLM larval density. The cultivars such as Succari and Musambi with a greater amount of leaf wax showed a lower density of CLM larvae. The study provides important information on wax related compounds involved in citrus-CLM interaction, which can help in developing an efficient control strategy for this destructive pest. [ABSTRACT FROM AUTHOR]