【摘要】 1983—1986年在河北省邯郸地区农科所采用自然感虫与人工控制虫量的开放式方法,设不同类型田、不同虫量的处理,研究了棉铃虫的为害作用、虫量与产值损失率的关系、棉株的补偿能力及其主要影响因素。同时研究了棉铃虫的自然种群生命表、虫量、农药的防治次数及防治效果,在此基础上组建了棉铃虫的动态EIL模型: 并综合考虑经济效益、生态效益和防治成本,用模糊综合评判的方法进行两级综合评判得出了高、中、低产田二、三代棉铃虫的经济阈值。经大面积大田示范验证,证明新经济阈值是可行的。更多还原

【Abstract】 The economic injury level and economic threshold of the cotton bollvorm, Heliothis armigera(Hbn.),were studied at Handan,Hebei in 1983-1986 from the following aspects:the injuries due to different generations of the bollworm and the population densities of each;the compensative ability of cotton plants;the life table of the natural population of the bollworm;the fertility levels of cotton fields; the relationship between the population density of the bollworm and the number of insecticidal applications and the efficiency of control. According to the results obtained and the concept of EIL, a model of EIL was formula ted as follows:where C is the cost of control,P is the unit price of lint cotton, M is the efficiency of control, T is the Tth generation, K is the type of cotton field, E is the rate of natural survival of the bollworm,A and b are constants of regression.Fuzzy integrated judgement was used to establish the economic threshold for the bollworm as follows:Fields with high yield level:The second generation: 34 larvae/100 plants;The third generation:16 larvae/100 plants.Fields with medium yield level:The second generation:23 larvae/100 plants;The third generation:10 larvae/100 plants.Fields with low yield level:The second generation:12 larvae/100 plants;The third generation: 7 larvae/100 plants.Actual use of these values in a large scale bollworm control at seven counties in Handan District verified that these economic thresholds are practicable for boll worm control.更多还原