一、用药时机把握不准打药务必抓住时机,只有了解病虫发生的规律,适时用药,方能奏效。例如治蝗虫必须在卵孵化高峰期用药,如果等到蚁螟已蛀入茎秆再用药,防效肯定不佳。二、施药方法不当病虫在作物上都有特定的危害部位,防治时要重点喷药。如防治蝗虫要对准心叶喷药,防治稻飞虱要对着稻株下部喷药。 First, the timing of medication is not allowed to fight drugs must seize the opportunity, only to understand the law of pests and diseases, timely medication, before they can work. For example, treatment of locusts must be at the peak of egg hatch, if the ants have been moulted into the stalks and then medication, control ineffective. Second, improper application methods Pests and diseases in the crop has a specific site of harm, prevention and treatment should focus on spraying. Such as prevention and control of locusts should be sprayed leaflets, planthoppers against the rice plant spraying the lower part.