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1.病虫害诊断错误 如将苗期立枯病误以为是蝼蛄、蛴螬危害;而有些由螨类引致的黄叶、卷叶、落叶又误以为是病菌所致。这样病当虫治,虫当病治,即使用药再多,也没有防治作用。 2.没有对症下药 农药是一类特殊的化学药物,有杀虫剂、杀菌剂、除草剂、杀螨剂、杀鼠剂等,此外还有植物生长调节剂、保鲜剂、防腐剂等,它们的作用和性质各不相同,防治对象和范围也不同,必须对症下药才能达到预期的效果。例如扑虱灵对白粉虱有特效,而对蚜虫无效;辟蚜雾对菜蚜特效,而对瓜蚜效果差。杀菌剂瑞毒霉对各种蔬菜霜霉病、疫病等高效,但不能防治白粉病。 3.施药时期不当 有害生物对农药有敏感期和不敏感期,应根据其发生规律,找出薄弱环节,及时施药,才能收到事半功倍的效果。初龄幼虫食量小,抗药性差,是药剂防治的有利时机;病害发生初期施药,将其控制和消灭在大量发生危害之前;杂草以萌芽至3叶前抗药性最弱。 4.用药量不准确 药量过高,不仅增加成本,还易造成药害,加重污染;药量少了,则达不到防治目的。另外,也
1. Insect pests and diseases diagnosis error If the blight at the seedling blight mistakenly thought it was scabies, scabies harm; and some caused by mites yellow leaves, curly leaves, leaves and mistakenly thought to be caused by bacteria. This disease when a worm, worm disease, even if more medication, there is no prevention and treatment. 2. There is no right medicine Pesticide is a special type of chemical drugs, insecticides, fungicides, herbicides, acaricides, rodenticides and so on, in addition to plant growth regulators, preservatives, preservatives, etc., their The role and nature of different objects and the scope of prevention is also different, must be the right medicine to achieve the desired results. For example, buprofezin has special effects on whitefly, but is not effective against aphids. Pest repellent has effects on cabbage aphids, but on cucurbits. Fungicide Reese mold on a variety of vegetables downy mildew, blight and other efficient, but can not control powdery mildew. 3. improper pesticide application Pesticide sensitive and insensitive to the period, should be based on its occurrence, identify the weak links, timely application of pesticides, in order to receive a multiplier effect. Early instar larvae have small appetite and poor resistance, which is a good time for the prevention and treatment of pesticides. In the early stage of the disease, pesticides are applied and controlled before being destroyed in large quantities. Before the weeds germinate to 3 leaves, resistance is weakest. 4. Inaccurate dosage medication is too high, not only increasing costs, but also easy to cause injury, aggravating the pollution; less drug, then reach the purpose of prevention and treatment. In addition, too