Moth scale-derived kairomones used by egg-larval parasitoid Ascogaster quadridentata to locate eggs of its host, Cydia pomonella

We determined that location of host (Cydia pomonella) eggs by Ascogaster qu adridentata is mediated by kairomones, investigated potential sources of th e kairomones and identified a blend of kairomones from the source that was attractive to A. quadridentata. In Y-tube olfactometer bioassays, female A. quadridentata were attracted to Porapak Q-collected Volatiles from female C. pomonella scales and eggs, but not to C. pomonella sex pheromone. Scales of C. pomonella were also attractive to male A. quadridentata. Coupled gas chromatographic-electroantennographic detection analysis of scale volatile extracts revealed numerous compounds that elicited responses from male or female A. quadridentata antennae, including heptanal, octanal, nonanal, dec anal, undecan-2-one, dodecanal, pentadecan-2-one, (Z)-6-pentadecen-2-one, ( Z)-9-hexadecenal, (Z)-6-heptadecen-2-one, and 3,7,11-trimethyl-2E,6E,10-dod ecatrien-1-ol acetate. A synthetic blend of these compounds at quantities a nd ratios equivalent to Porapak Q scale volatile extract was attractive to female A. quadridentata in a Y-tube olfactometer bioassay.