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近十年来,由于耕作制度的变化,改变了粮菜间作的习惯,保护地栽培面积迅速扩大,重作连茬多,为病虫的滋生繁殖提供了良好的环境条件,加之不合理的使用农药,使病虫抗药性增强,害虫天敌大量被杀伤,严重地破坏了生态平衡,病虫害越来越重,蔬菜上农药残留量越来越高。1979年南昌市抽样检查小白菜、甘兰中“六六六”残留量超过
In the recent decade, due to the change of farming system, the habit of intercropping food and vegetables has been changed. The cultivated area in protected areas has been rapidly expanded. The continuous cultivation of heavy crops has provided good environmental conditions for the breeding of pests and diseases. Combined with unreasonable use of pesticides , So that pest resistance increased, a large number of pest natural enemies were killed, seriously undermining the ecological balance, pests and diseases more and more heavy, vegetable pesticide residues higher and higher. 1979 Nanchang sampling cabbage, cabbage in the “BHC” residual more than