Abstract: The electroantennogram (EAG) responses of female and male beetles of Xylotrechus rusticus (L.) to 10 volatiles were tested, including salicylaldehyde (0.95 μmol/μL) from poplar, the host plant, and phytol (0.3 μmol/μL), R-(-)-α-phellandrene (0.4 μmol/μL), (1R)-(+)-α-pinene, (1S)-(-)-α-pinene, (1S)-(-)-β-pinene, (+)-3-carene, ocimene, β-myrcene and turpentine (0.6 μmol/μL) from non-host plant. The results showed that the 10 volatiles could evoke very significant EAG responses (P<0.01) of the adults compared with the control, paraffin. The females exhibited stronger EAG responses to turpentine, salicylaldehyde, (1R)-(+)-α-pinene, (1S)-(-)-α-pinene, while (1R)-(+)-α-pinene and turpentine could induce stronger EAG responses to males. The EAG responses of female and male adults to salicylaldehyde, (1R)-(+) -α-pinene and ocimene had no significant differences (P>0.05), but to the rest 7 volatiles had remarkable difference (P<0.01). The responses and behaviors of females to different doses of turpentine, (1R)-(+)-α-pinene, (1S)-(-)-α-pinene and salicylaldehyde, were further tested. The tested concentrations of salicylaldehyde were 0.000095, 0.00095, 0.0095, 0.095, 0.95, and 0.19 μmol/μL; the rest compounds with the same concentrations of 0.00006, 0.0006, 0.006, 0.06, 0.6, and 0.12 μmol/μL. With the concentration increased, the female EAG response to turpentine, salicylaldehyde and (1R)-(+)-α-pinene increased accordingly and kept steady when the concentration of salicylaldehyde reached 0.95 μmol/μL and those of turpentine and (1R)-(+)-α-pinene reached 0.6 μmol/μL. When the concentration were less than or equal to 0.6 μmol/μL, turpentine  exhibited repellent effect to females and had the best effect at 0.6 μmol/μL (P<0.01); whereas, it showed lure effect at 0.12 μmol/μL (P>0.05). When the concentration were lower than 0.095 μmol/μL, salicylaldehyde had no obvious directional action to female (P>0.05); while higher than 0.095 μmol/μL, it exhibited repellent action (P<0.05). The females showed no distinct directional behavior to (1R)-(+)-α-pinene and (1S)-(-)-α-pinene.

Key words: Xylotrechus rusticus, plant volatiles, repellent, lure, EAG response, behavior, Y-tube olfactometry