防治虫害的目的在保产,因此需要研究各类虫害对作物的为害而引起的产量损失,以便制定出合理的防治指标,从而适时进行防治达到最大的经济效益。作物产量损失是由各种因素相互影响的结果,因此是一个很复杂的问题。有一些因子不好控制(如天气、土壤类型等),其他如种植材料、耕作方式、肥料、杀虫剂等也因目的不同而有改变。但无论如何,应当研究投资与获得最高利润的指标。从植保的观点来说就是要保证作物损失最小,并获得 The purpose of pest control is to protect the production, therefore, it is necessary to study the yield loss caused by the damage caused by various pests to crops in order to formulate a reasonable prevention and control index so as to achieve the greatest economic benefits in a timely manner. Crop yield loss is a result of the interplay of various factors and is therefore a complex issue. There are some factors that are not well controlled (weather, soil types, etc.) and others, such as planting materials, farming methods, fertilizers, pesticides, etc., also vary depending on the purpose. In any case, however, one should study the indicators of investment and maximum profit. From the plant protection point of view, it is necessary to ensure that the loss of crops is minimal and available