对害虫具自然控制能力的益害比指标模型的研究——1 益害比指标模型的建立与分析

本文通过害虫种群自然控制的阻滞增长摸型分析天敌对害虫具控制能力的益害比指标在设定害虫种群呈logistic曲线增长的基础上,通过稳定性钟分析,建立了具自然控制能力的益害比指标模型。摸型分析表明、天敌对害虫的控制能力大小由害虫种群增长率、害虫种群数量、天敌相互干扰以及环境容纳量等因素决定。这些因素随季节变化而发生变化,因而具控制能力的益害比指标并非一恒定值,而是随时发生变化。故此,具控制能力的益害指比标只能根据某时的实际情况,利用本文提出的摸型或建摸方法来确定。本文的研究对害虫测报和生防工作具有实际意义。

TUDYON INDEX MODEL OF ENEMY-PEST RATIO OF HAVING NATURL CONTROL TO INSECT: I. CCNSTRUCTION AND ANALYSES OF ENEMY-PEST RATIO INDEX MODEL

A bloched increase model of pest insect population with natural control was used to analyse the ratio index of enemy to pest under which the enemy can co- ntrol the increase of pest population. Based on the assumption of logistic increase of logistic increase of pest pooulation, an index model of enemy-pest ratio of having natural control to pest was introduced through the analyses of stability. This model indicates that: the control forces of enemy to pest are determined by the increase rate and number of pest population, the eating number of enemy and the environmental capacity for pest and so on. Since these factors change with time, the enemypest ratio index change with time too, So the ratio index is not a constant but a variable Therefore, the enemy-pest ratio index can be determi- ned only by the actual situation of certain time through using this model or using the method of developing this model. The results of this paper have practical significance on pest prediction and on biological control experience.