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通过１０多年系统调查棉田捕食性天敌及棉铃虫卵的消长动态，与８０年代相比，９０年代棉田捕食性天敌种类和数量锐减，种群结构发生变化，增殖速率十分缓慢。相关分析表明，化学农药使用次数增加是棉田天敌下降的主要原因，其次是气候条件，此外，农药品种的变化对天敌也有较大影响。对比分析棉铃虫与天敌系统调查资料，得出棉田天敌的控制期、药剂的控制期和天敌的保护期，为保护利用天敌和药控棉铃虫相协调提供科学依据。
After more than 10 years of systematic investigation of the dynamics of the predatory natural enemies and the growth and development of cotton bollworm eggs in cotton fields, the species and numbers of predatory natural enemies dropped sharply in the 1990s compared with those in the 1980s. The population structure changed and the rate of proliferation was very slow. Correlation analysis showed that the increase of the number of chemical pesticides used was the main reason for the decline of natural enemies in cotton fields, followed by the climatic conditions. In addition, the changes of pesticide varieties also had a great impact on the natural enemies. By comparative analysis of the investigation data of cotton bollworm and its natural enemies, the control period of natural enemies and the control period of natural enemies and the protection period of natural enemies were obtained, providing a scientific basis for the protection and utilization of natural enemies and drug-control bollworm.