Evaluation of Rice Stem Borer's Damage Chilo suppressalis Walker (Lepidoptera: Pyralidae) on Different Rice Varieties

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Abstract

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.‎

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