PROXIMITY OF RELEASE POINTS OF PHEROMONE COMPONENTS AS A FACTOR CONFUSING MALES OF THE SPOTTED STEM BORER, CHILO-PARTELLUS, APPROACHING THETRAP

The effect of proximity of the release points of the two pheromone com ponents (Z)-11-hexadecenal and (Z)-11-hexadecen-1-ol of the spotted st em borer, Chilo partellus (Lepidoptera: Pyralidae) on behavior of the males and on trapping efficiency was investigated. Separating the disp ensers of the two components in the trap by a mem 3 cm resulted in a t hreefold decrease in trap performance, compared to very close release of the components. The result is attributed to possible distortion of the pheromone signal, resulting in confused behavior of C partellus ma les in the vicinity of the trap. The ethological and practical implica tions of the phenomenon are discussed.