Abstract:Orientation responses of Anagrus nilaparvatae to rice plants treated with imidacloprid were studied using Y-tube olfactometer. The results indicated that imidacloprid, or different rice varieties treated with imidacloprid had no effect on the orientation behaviour of A.nilaparvatae. A.nilaparvatae exhibited much preference to volatiles emitted from rice plants treated with imidacloprid. When the density of N.lugens was 10 females per plant, a majority of the wasps were attracted to volatiles released from rice plants treated with low concentration of imidacloprid, but not to high concentration treatment. Then, 40 components were collected from headspace of rice plants treated with imidacloprid with solid phase microextractrion (SPME), 14 of which were identified by gas chromatography coupled with mass spectrometry (GC-MS). Imidacloprid treatments did not result in the emission of new compounds, but rather the proportions (% of total peak area) among the compounds in the blend were altered. The proportions of 8 components had significant differences in 3 levels of imidacloprid concentration treatments. Furthermore, the proportions of some components were significantly changed due to interactions between concentrations of imidacloprid and rice varieties, densities of N.lugens, days after treatments.