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本文应用生命表及Morris-Watt数学模型作为分析害虫天敌作用的方法。 文内应用了M-值,即如果组份“i”被除去,种群数量发展趋势指数“I′”将比原有的种群数量发展趋势指数“I”将增加M(si)倍。根据1976～1981年稻纵卷叶螟第二世代平均生命表的组份分析,M-值表示出天敌起着控制种群数量的重要作用。按照推算,如果排除了捕食性天敌,寄生性天敌及病原,种群数量发展趋势指标将比原来的增长358.69倍,或这种害虫的第三代将比第二代种群数量增长31.78倍。 应用生命表方法及Morris-Watt数学模型分析,在对稻纵卷叶螟不同处理的试验中,广谱性杀虫剂(1.5％1605+3％666)在施用一天后或数天后引起高死亡率,但同时由于杀死天敌的副作用,其种群数量发展趋势指标H对照为高。散放松毛虫眼峰的处理中,引起不孵的死亡百分率低于化学杀虫剂引起一龄幼虫的死亡。由于稻纵卷叶螟种群数量于卵期开始下降,相对来说,天敌的作用于幼虫期及蛹期增长了,种群数量增长趋势指标下降至0.067,表现出明显的好效果。 文内还讨论了植物抗虫性与天敌的关系,应用了简单的数学模型以估计植物的抗虫性指标。
In this paper, the life table and the Morris-Watt mathematical model are used as a method to analyze the effect of natural enemies of pests. The M-value is applied in the text that if the component “i” is removed, the population trend index “I” will increase by M (si) times the original population trend index “I”. Based on the compositional analysis of the average life table of the second generation of rice leaf roller Cnaphalocrocis medinalis from 1976 to 1981, the M-value indicates that the natural enemies play an important role in controlling the population size. It is estimated that if the exclusion of predators, parasitic natural enemies and pathogens, population trends in the number of indicators will be 358.69 times the original increase, or the third generation of pests than the second generation population increased 31.78 times. Using the life table method and the Morris-Watt mathematical model, the broad-spectrum insecticides (1.5% 1605 + 3% 666) caused high mortality on day one or several days after the application of different treatments to C. medinalis Rate, but at the same time due to the side effects of killing natural enemies, the trend of population quantity index H was high. The percentage of uncapped deaths during the release of the pine eye drops was lower than the first-instar larvae killed by chemical insecticides. As the population of Cnaphalocrocis medinalis began to decline in the egg stage, the effects of natural enemies increased relatively at larval stage and pupal stage, and the trend of population growth index decreased to 0.067, showing a good effect. The paper also discussed the relationship between plant pest resistance and natural enemies, and applied a simple mathematical model to estimate plant insect resistance index.