Formate Analogs as Antagonists of the Sex Pheromone of the Honeydew Moth, Cryptoblabes gnidiella: Electrophysiological, Behavioral and Field Evidence

Abstract

Cryptoblabes gnidiella Milliére (Lepidoptera: Pyralidae) is an economically important exotic pest of vineyards in Southern Brazil and Uruguay. The sex pheromone of C. gnidiella was identified as a mixture of (Z)-11-hexadecenal and (Z)-13-octadecenal, and has been used to monitor populations of this pest in Israel. The development of mating disruption for this species may be hampered by the chemical instability of the natural pheromone components. Therefore, studies on more stable pheromone analogs may provide tools for a control strategy based on behavior-modifying chemicals. We report here the electrophysiological and behavioral responses of C. gnidiella males to (Z)-9-tetradecenyl formate and (Z)-11-hexadecenyl formate, structural analogs of the pheromone components. In gas chromatography-electroantennogram detection (GC-EAD) studies, both analogs elicited responses from C. gnidiella male antennae. Pre-exposure to the formates did not affect the subsequent EAD responses to the natural pheromone components. The formates acted as pheromone antagonists in wind tunnel tests, inhibiting the responses of males toward both synthetic pheromone and calling females. In the field, captures of males in pheromone-baited traps decreased, in a dose-response pattern, when different amount of formates were added to the pheromone. These pheromone antagonists, thus, are potentially useful as mating disruptants for C. gnidiella in commercial vineyards.