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了解和掌握病虫数量变化规律,是做好病虫防治工作的重要前提.一般地说,估测病虫发生数量达不到防治指标、为害损失超不过经济允许水平,就可不防治;当发生量有明显上升趋势,但田间天敌足以抑制病虫发展时,也不必防治;当病虫数量超过防治指标、天敌数量不足以控制其发展或为害损失超过经济允许水平,那就要从速防治.下面简介病虫发生数量的预测方法.
Understanding and mastering the regularity of changes in the number of pests and diseases is an important prerequisite for the prevention and control of pests and diseases.Generally speaking, it is not necessary to control the number of pests and insect pests that can not reach the prevention and control index, and the damage and loss exceed the economic allowable level. However, the natural enemies of the field are sufficient to suppress the development of pests and diseases and do not have to be controlled. When the number of pests and diseases exceeds the control index and the quantity of natural enemies is insufficient to control their development or cause damage to exceed the allowable economic level, they should be prevented and controlled as soon as possible. Introduction Predict the number of occurrence of pests.