|MILLAR, JOCELYN - University Of California|
Submitted to: Journal of Chemical Ecology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/7/2009
Publication Date: 12/20/2009
Citation: Guedot, C.N., Millar, J.G., Horton, D.R., Landolt, P.J. 2009. Identification of a Sex Attractant Pheromone for Male Winterform Pear Psylla, Cacopsylla pyricola. Journal of Chemical Ecology. 35:1437-1447.
Interpretive Summary: Pear psylla is a major pest of commercial pears in North America and Europe. Monitoring methods are needed for growers to use to determine the need for control measures. Scientists at the USDA-ARS in Yakima compared the chemical profiles of whole-body washes from male and female winterforms and identified a female-produced sex attractant pheromone that is attractive to males and not to females. This study provides evidence through chemical analyses, behavioral bioassays, and a field experiment that 13-methylheptacosane is a sex attractant pheromone for C. pyricola winterform males. This is the first identification of a sex pheromone in the Psyllidae. This sex attractant pheromone could be developed as a lure for eventual use in monitoring and pest management.
Technical Abstract: Pear psylla, Cacopsylla pyricola (Förster) (Hemiptera: Psyllidae), a major economic pest of pears, have been shown to use a female-produced sex attractant pheromone. We compared the chemical profiles obtained from cuticular extracts of diapausing and post-diapause winterform males and females, with goals to isolate and identify the pheromone. Post-diapause females produced significantly more of the cuticular hydrocarbon 13-methylheptacosane than post-diapause males and diapausing females. In olfactometer assays, males were attracted to synthetic racemic 13-methylheptacosane whereas females were not, indicating that the behavioral response to this chemical is sex-specific. Furthermore, 13-methylheptacosane was as attractive to males as a cuticular extract of females, suggesting that this chemical was largely responsible for the female attractiveness. A field trapping study showed that males but not females were attracted to 13-methylheptacosane, confirming the olfactometer results. This study provides evidence through chemical analyses, behavioral bioassays, and a field experiment that 13-methylheptacosane is a sex attractant pheromone for C. pyricola winterform males. This is the first identification of a sex pheromone in the Psyllidae. Our results open the path to developing monitoring tools, and possibly new strategies for integrated pest management of this insect.