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对河南省兰考县１９８５ ～１９９５ 年泡桐大袋蛾治理情况、虫口密度以及寄生率的数据进行分析，结果表明：按受害面积可以将泡桐大袋蛾的发生划分为蔓延期（１９８５ ～１９９０） ，这时的年平均扩散速率为１１５ ％ ；高峰期（１９９１ ～１９９２） ，年平均扩散速率约为０ ％ ；消亡期（１９９３ ～１９９５） ，这期间大袋蛾种群急剧消亡．防治措施能有效保护泡桐叶片．但由于对有虫树木不能彻底地防治，因而不能有效防止害虫的扩散；同时，这种防治措施也不是导致大袋蛾种群消亡的原因．数据分析还表明大袋蛾的发生周期更象是与寄生天敌相互作用的结果，天敌的作用是大袋蛾种群消亡的促进因子之一，但不是决定性的因子．本文提出了泡桐大袋蛾种群破产阈值的观点，并计算得到破产阈值指标 Ｔｃｒ ＝ ３５５ 头／ 百叶，即当幼龄（１ ，２ 龄） 虫口密度超过３５５ 头／ 百叶、扩散速率为０ ％ 时，大袋蛾种群将自然、迅速地消亡．因为极高的虫口密度导致了剧烈的种内竞争，并且环境负荷量已无法满足种群的需要．
The results showed that the occurrence of Paulownia mongolica can be divided into spreading period (1985 ~ 1990) according to the area of victimization, and the data of parasitism rate and management density of Paulownia moth, from 1985 to 1995 in Lankao County, Henan Province, were analyzed. The annual average rate of diffusion was 115%. During the peak period (1991-1992), the annual average rate of diffusion was about 0%. During the period of extinction (1993-1995), the population of the giant-bagged moths had rapidly disappeared. Control measures can effectively protect the leaves of paulownia. However, the insects can not be effectively prevented because the insects can not be completely prevented and controlled. At the same time, the prevention and control measures are not the cause of the demise of the giant moths. The data analysis also suggests that the cycle of the moth is more likely to be the result of an interaction with parasitic natural enemies whose role is one of the contributing factors to the demise of the moth population but not the decisive factor. In this paper, we put forward the viewpoint of bankruptcy threshold of Paulownia moth population and calculate the threshold value of bankruptcy Tcr = 355 heads / leaf. When the population density of young (1 and 2 years old) exceeds 355 head / leaf and the diffusion rate is 0% Large bag moth population will naturally and quickly die. Because of the high density of insects caused intense intraspecific competition, and the amount of environmental burden has been unable to meet the needs of the population.