IPP-10 is a novel neonicotinoid insecticide recently developed in China and has good activity against sucking insects. Studies were carried out to investigate the activity of IPP-10 against Rhopalosiphum padi L. The results demonstrated that IPP-10 had both contact and systemic activity, including acropetal and basipetal translocation in wheat vascular bundles. Starved R. padi were allowed to stay on wheat treated with a sublethal dose of IPP-10. The results of studying their feeding behaviour from an electrical penetration graph (EPG) revealed a decrease in total time and bout duration of xylem and phloem ingestion, but the total time and bout duration of phloem salivation were significantly prolonged. The frequency (7.03 +/- 0.49 Hz) of the xylem ingestion waveform produced by aphids on wheat treated with IPP-10 was significantly lower than that of blank control aphids (8.20 +/- 0.30 Hz). Consequently, aphids born on wheat treated with IPP-10 were obviously lighter and less fecund than the control aphids. These tests indicated that IPP-10 had both contact and systemic activity, with sublethal effects resulting in reduction in R. padi feeding behaviour, growth rate and fecundity.