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第二代菜青虫为害甘蓝损失模型及防治指标的研究
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摘要:
1984——1985年在淮南市,通过田间塑料纱网大棚接虫,进行了第二代菜青虫为害甘蓝的损失测定,利用1984年试验数据建立了虫口密度x与甘蓝损失率y之间的Weibull损失模型(回归式)为y=1-exp{-((x-0)/47.4042)~(0.9569)},结果1985年田间试验实测值与理论值之间误差很小。本文还根据经济阀值原理,利用Weibull损失模型,二代菜青虫幼虫期生命表及幼虫各龄食叶量等导出幼虫三龄末防治指标X_(ET(3))=4.2864(头/株),即429头/百株;幼虫四龄末防治指标X_(ET(4))=2.1043(头/株),即210头/百株。
关键词:  菜青虫,甘蓝,Weibull模型,防治指标
DOI:
基金项目:
STUDIES ON THE LOSS MODEL OF CABBAGE BY THE SECOND GENERATION PIERIS RAPAE AND CONTROL INDEX
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Abstract:
Cabbage infested by the 2nd generation pieris rapae was studied to measure the yield loss and to determine the control insex for Huainan Area from 1984 to 1985. A loss model, Weibull' S model, is established between the population density x and the rate of yield loss y:Y=1-exp{-(x-0/47.4042)~(0.9596)}Based on economical threshold, life table, and defoliation amount, the present study suggests a control index for the 3rd instars concluded as X_(ET(3))=429 (per100 cabbages)and for the 4th instars as X_(ET(4))=210.
Key words:  Pieris rapae, Cabbage, Weibull's model, Control index.

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