Geraniol, E-3,7-dimethyl-2,6-octadien-1-ol, as the alarm pheromone of the sycamore lace bug Corythucha ciliata (Say).

Although adult sycamore lace bugs Corythucha ciliata (Say) show no sign of aggregation, nymphs at all developing stages are gregarious. When an individual nymph in the center of a colony was squashed with a needlepoint, proximate nymphs showed evasive behavior. The same evasive reaction was produced by exposing aggregated nymphs to nymph hexane extract. The active component, E-3,7-dimethyl-2,6-octadien-1-ol, geraniol, was responsible for the evasive behavior, and identified as the alarm pheromone. One nanogram of the alarm pheromone elicited activity similar to that in a third instar nymph. Presence of 2-acylcyclohexane-1,3-diones and their 4-hydroxy analogues are reconfirmed as nymph-specific components, though their biological significance remains unknown.