Synthetic Sex Pheromone Components Disrupt Orientation, but not Mating, in the Fall Cankerworm, Alsophila pometaria (Lepidoptera: Geometridae)

Abstract

Small-plot field experiments were done to determine whether synthetic sex pheromone components of the fall cankerworm, Alsophila pometaria (Harris), released individually or as a ternary blend from several point sources, could 1) disrupt orientation of male moths to pheromone-baited traps and 2) reduce incidence of mating in females. Three experiments were carried out using red rubber septa and Hercon laminate chips as releasers. In the first two the releasers were arranged at several points around one or two elm trees in each experimental plot; in the third experiment the releasers were directly attached to tree trunks. In all experiments the ternary blend, as well as the two tetraene components, (Z,Z,Z,E)-3,6,9,11-nonadecatetraene and (Z,Z,Z,Z)-3,6,9,11-nonadecatetraene, when deployed singly, showed excellent disruption of orientation of males to pheromone-baited traps but none of these treatments reduced incidence of mating in females collected from trees in experimental plots. (Z,Z,Z)-3,6,9-nonadecatriene, the third pheromone component, was not effective in disrupting either male orientation or mating. Behavioral observations indicated that in untreated plots males tended to orient to trees initially and then searched for females on the tree trunk and on the ground close to the trunk. The identical behavior exhibited by males in pheromone-permeated plots may have contributed to our inability to demonstrate mating disruption through application of pheromones. A high male/female ratio also appeared to contribute to lack of mating reduction.