عنوان مقاله [English]
نویسندگان [English]چکیده [English]
In order to evaluation of rice stem borer's damage (Chilo suppressalis Walker), on rice cultivars an experiment was carried out by two factors, (three cultivars and five spraying times), in completed randomized block design an factorial sampling was conducted on the hills infested to deadhearts (D.h), whiteheads (W.h) and yield loss. Five hills were randomly selected from each plot and evaluated. The effects of variety and spraying times on different variables (except yield variables) were significant (p ? 0.01). The percentage of D.h and W.h at the first year were higher than other years. Also, the D.h, W.h and yield loss on Tarom-mahali cultivar was higher than others (p ? 0.05). The means of percentage D.h and W.h, 1.34, 2.49 were estimated, in the three years, respectively. Also, yield loss was estimated 12.20 kg/hec. Compare with chek treatment. Correlation coefficient between D.h and yield -0.37 and W.h with yield were -0.35 (p ? 0.01). Tarom-mahali cultivar was more sensitive to rice stem borer’s damage than Khazar and Nemat cultivars.