Submitted to: Journal of Chemical Ecology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/24/2009
Publication Date: 9/11/2009
Citation: Lapointe, S.L., Stelinski, L., Evens, T.J., Niedz, R.P., Hall, D.G., Mafra-Neto, A. 2009. Sensory imbalance as mechanism of mating disruption in the leafminer, Phyllocnistis citrella: Elucidation by multivariate geometric designs and response surface models. Journal of Chemical Ecology. 35:896-903. Interpretive Summary: The citrus leafminer is a major pest of citrus throughout the world. The larvae feed within the leaf, producing a serpentine mine that results in distortion and loss of photosynthetic capacity, thereby reducing yield. In addition to direct damage, mining by this species increases the susceptibility of citrus leaves to infection by citrus canker, an important disease of citrus. We experimentally determined optimal pheromone blends for attraction and mating disruption and gained insight into the mechanism of disruption for control through application of appropriate experimental design. We used mixture-amount approaches to quantify optimal pheromone blends and concentrations for both attraction and mating disruption in a series of field experiments conducted in Florida citrus groves. A more complete understanding of the mechanism of mating disruption should contribute to refinement of deployment techniques, increased efficacy, and improved economic returns for pheromone product manufacturers and end users of pheromone-based products. We believe the methods employed here to be of wide applicability within this field and many other fields of biological inquiry where responses to proportion and amount of mixture components are measured.
Technical Abstract: Experimental designs developed to address mixtures are ideally suited for many areas of experimental biology including pheromone blend studies because they address the confounding of proportionality and concentration intrinsic to factorial and one-factor-at-a-time designs. Geometric multivariate designs coupled with response surface modeling allowed us to identify optimal blends of a two-component pheromone system for attraction and mating disruption of the leafminer moth Phyllocnistis citrella, a major pest of citrus throughout the world. Field trials confirmed that the natural 3:1 blend of (Z,Z,E)-7,11,13-hexadecatrienal:(Z,Z)-7,11-hexadecadienal is most effective as an attractant for male moths. However, the response surface generated in mating disruption trials revealed that the triene component alone was more effective than the natural blend in disrupting trap catch. While either individual component was effective at disrupting mating in field trials, (Z,Z,E)-7,11,13-hexadecatrienal was approximately 13 times more effective compared with (Z,Z)-7,11-hexadecadienal alone. In addition, the application of geometric design and response surface modeling to field studies provided insight into the mechanism of mating disruption and strongly support sensory imbalance as the operating mechanism for this species.