Abstract: A linear forecasting model to monitor the spring emergence and flight pattern of the overwintering generation of the rice stem borer, Chilo suppressalis (Walker), in northeastern China was developed.The model is based on the correlation between the pheromone trap catches and corresponding degree-days (DDs) calculated from 1 March above the threshold of 12.9℃ in Liuhe, Jilin in 1999-2000. Overwintering adults generally begin to appear in Liuhe rice fields after 126.995 cumulative DDs. The DD accumulations from 1 March corresponding to the capture of 10%, 50% and 90% of all male moths throughout the flight season were 238.323, 339.418 and 483.398, respectively. The comparison of the predicted results with the observed data in three years (2002-2004) in Changchun city verified the reliability of the log-probit line forecasting model,which indicated that the error of DDs varied from 3.882 to 26.943, and the corresponding error of dates (between the observed and predicted dates) was 0-3 days. In rice-producing regions in northeastern China, farmers could use the results of the forecasting model to help make decisions for the effective control of the rice stem borer.

Key words: Chilo suppressalis, forecasting model, degree-days, trap catches