Studies on the distribution pattern of egg-mass population of rice striped borer, Chilo suppressalis Walker, in rice fields [in China]
1989
Huang Hanwen | Li Yunbi | Kang Xingquan (Huazhong Agricultural Univ., Wuchang (China). Dept. of Plant Protection)
Field surveys were conducted in 1983-1984 in Wuchang region, Hubei Province, to evaluate the distribution pattern of egg-mass population of rice striped borer, Chilo suppressalis Walker, in rice seedling fields and paddy fields. With the areas of approximate 4.50 and 6.25 square metres as the cardinal quadrants of rice seedling and paddy fields respectively, the observations showed that the distribution pattern varied with egg-mass densities. Based on the regression analysis of mean-crowding (m)/mean-density(m) on meandensity(m), it was obtained that when egg-mass density was lower than 0.962 and 0.897 egg-masses per quadrant in seedling and paddy fields respectively, the population was aggregatedly distributed, and beyond the above densities, the population would tend gradually to random distribution. The factors caused the egg-mass population aggregated were also discussed in this present paper.
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