Submitted to: Journal of Chemical Ecology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/20/2004
Publication Date: 4/15/2005
Citation: Jumean, Z., Gries, R., Unruh, T.R., Rowland, E., Gries, G. 2005. Identification of the larval aggregation pheromone of codling moth, Cydia pomonella. Journal of Chemical Ecology. 31(4):911-924. Interpretive Summary: Codling moth, the proverbial worm in the apple, remains the most important pest of apples and pears worldwide. Many studies have investigated chemical communication in this insect in order to understand this pest and discover methods to control it. A recent behavioral study demonstrated that mature larvae of codling moth cue in on chemical signal produced by other larvae while spinning their cocoons resulting in larval l aggregations. While this aggregation behavior is not fully elaborated this paper continues the effort by identifying the chemical composition of the aggregation pheromone and showing which minimal number of chemical components are required to elicit aggregation behaviors. The pheromone and synthetic blends of a the active components are now being tested as means to attract larvae for pest control.
Technical Abstract: Mature larvae of the codling moth, Cydia pomonella L. (Lepidoptera: Olethreutidae), exit the fruit and seek sites suitable for pupation. Spinning cocoons in such sites, larvae produce a complex, cocoon-derived blend of volatiles recently shown to attract and/or arrest both conspecific larvae and the prepupal parasitoid Mastrus ridibundus Gravenhorst (Hymenoptera: Ichneumonidae). Here we report components of this blend that constitute the pheromone of fifth-instar C. pomonella larvae. Thirty-one two-choice laboratory experiments showed that a blend of synthetic (E)-2-octenal, (E)-2-nonenal, sulcatone and geranylacetone in combination with either 3-carene and/or three saturated aldehydes (octanal, nonanal, decanal) elicit significant behavioral responses by C. pomonella larvae. In on-tree experiments, with corrugated cardboard (CB) bands as pupation sites for larvae affixed to tree trunks, and with laboratory-reared larvae released onto such trees, significantly more larvae cocooned in those halves of CB bands baited with cocoon-spinning conspecific larvae, or with synthetic pheromone components, than in unbaited control halves of CB bands. With the larval aggregation pheromone identified in this study, there might be an opportunity to manipulate C. pomonella larvae in commercial fruit or nut orchards.