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作者从1978—1983年对棉红蜘蛛的为害进行研究。结果表明,棉花苗期受害后,棉株高度降低,果枝数和青铃数减少。蕾铃期受害后,青铃数明显减少。棉株受害后影响产量。为害指数(x)与减产率(y)的关系式为:苗期y=10.40x±1.21(0≤x≤2.36),蕾铃期y=12.53x±1.5(0≤x≤2.5)。在田间调查时,可根据红斑株率(n)与红斑株平均为害指数(m)的关系式m=0.2165+0.00889n±0.14推算出减产率。利用y=10.40x±1.21,y=12.53x±1.5和m=0.2165+0.00889n±0.14,结合当地棉花的生产水平,可确定以红斑株率表示的防治指标。红斑株率易于调查和推广应用。
The author studied the damage of cotton spider mites from 1978-1983. The results showed that the height of cotton plant decreased, the number of fruit branches and the number of green bell decreased after cotton seedlings were damaged. After the damage of budding period, the number of green bell decreased obviously. Affected yield after cotton plant damage. The relationship between the damage index (x) and yield (y) was: seedling y = 10.40x ± 1.21 (0≤x≤2.36), budding period y = 12.53x ± 1.5 (0≤x≤2.5). In the field investigation, the rate of yield reduction could be calculated based on the relationship between erythema strain rate (n) and the average damage index (m) of erythema plant (m = 0.2165 + 0.00889n ± 0.14). The control index of erythema plant can be determined by y = 10.40x ± 1.21, y = 12.53x ± 1.5 and m = 0.2165 + 0.00889n ± 0.14 according to the local cotton production level. The erythema strain rate is easy to investigate and popularize.