记者近日在山东采访时,有农民和经销商反映,在病虫害防治过程中,只有施药量不断增加的情况下才能有防治效果。山东农业大学植保学院的王开运教授认为,国内使用农药品种大多数为过专利期产品,一些所谓新农药在中国连续应用都在20年以上,其药效逐年降低,加之不能科学地施用,使农业有害生物的抗药性水平提高。如何 Reporters recently interviewed in Shandong, farmers and distributors reflect the pest control in the process, only the case of increasing doses of pesticides to have control effect. Professor Wang Kaiyun from Plant Protection College of Shandong Agricultural University believes that the majority of pesticide varieties used in China are over-patent products. Some of the so-called new pesticides are used continuously for more than 20 years in China, and their efficacy is decreasing year by year. In addition, they can not be applied scientifically to make agriculture Pest resistance levels improve. how is it