Abstract: The presence of Aphis gossypii on Eupatorium adenophorum may suggest a new way of controlling the invasive plant. In the laboratory we tested the behavioral responses of A.gossypii and Coccinella septempunctata to volatiles from E. adenophorum were tested with Y-olfactometer, and the chemical com ponents of these volatiles were analyzed with GC-MC. The results of A. gossypii bi-choice tests with Y-olfactometer showed that the choice of A. gossypii fed on E. adenophorum to E. adenophorum odor reached 62.5% when cotton existed, whereas the choice to cotton odor was 37.5%. The choice of A. gossypii fed on cotton to E. adenophorumodor reached 30% when cotton existed, whereas from the choice to cotton odor was 70%. The results of selective test of C. septempunctata from E. adenophorum infested by A. gossypii showed the choice to odor from E. adenophorum infested by A. gossypii was 29.2%, and the choice to cotton odor was 70.8%. The selection of C. septempunctata to aphid odor had no significant differences after both plants were removed. The selection of C. septempunctata to odor from aphids fed on E. adenophorum reached 46.7%, whereas the choice to odor from aphids fed on cotton was 53.3%. GC-MC analysis of the volatiles from E. adenophorum revealed that the main volatile compounds were α-pinene, camphene, β-pinene, 2-carene, and α-phellandrene.

Key words: Eupatorium adenophorum, volatile compounds, behavioral response; Aphis gossypii, Coccinella septempunctata