Planters often have poor control effects when using pesticides to control diseases, pests and weeds. In the case of unknown reasons and without correct guidance, the dosage, concentration, frequency and repeated use of drugs will often be increased, and even the use of highly toxic pesticides and other prohibited pesticides, in order to achieve better control effects. This not only increases the cost of medication and labor for users, but also puts pressure on our agricultural food safety, environmental protection and sustainable agriculture. In particular, the author sorted out and summarized 10 reasons for the poor control effect, with a view to discussing, studying and seeking more reasonable ways and means to improve the control effect and utilization rate of pesticides.

1、 Backward application equipment

At present, the domestic spraying equipment is mainly backpack type and stretcher type. In addition, the drug supply system is simple and backward, and the phenomenon of "running, emitting, leaking, dripping and blocking" can be seen everywhere, which often leads to uneven atomization effect and poor spray quality. In addition, the commonly used high-volume method is easy to cause large and uneven fog drops, large fog drops are easy to lose, small fog drops are easy to drift and volatilize, and poor adhesion, which leads to low pesticide utilization.

2、 Spray technology is not up to standard

The occurrence, harm and development of diseases and insect pests will have a major hazard location or target on crops. For contact pesticides, if the spray can not accurately hit the target, it is difficult to have a better control effect; For the internal absorption pesticide, if the droplets cannot be evenly distributed on the target, there will be no good internal absorption effect, and the control effect will be greatly reduced. For example, for the prevention and control of red spider, try to spray the liquid medicine evenly on the back of the leaves (contact killing) or the front of the leaves (internal suction); The control of corn borer should be done with heart-leaf pesticide; To control planthopper and sheath blight, it is necessary to aim at the lower part of the plant; To control leaf roller, rice blast and bacterial blight, attention should be paid to upper leaf spray.

3、 Improper selection of application liquid

The amount of liquid medicine applied refers to the amount of liquid medicine sprayed on the farmland per unit area. At present, the conventional spray in China is mainly high volume method and medium volume method, which use large amount of water and can be evenly wetted. However, there is less liquid medicine on the target or crop surface, and the liquid medicine is wasted and lost seriously. Modern agriculture needs modern plant protection concepts. We also need to select appropriate water consumption according to local conditions. When necessary, we need to add appropriate spray additives (such as organic silicon, mineral oil, vegetable oil), which can be used together with spray devices (nozzles) and pesticide preparations to increase the retention of liquid medicine on the target or crop surface, and promote the stability of drug efficacy.

4、 Improper mixing of chemicals

Generally, the mixed use of two or more agents with different action modes and mechanisms can not only improve the control effect and concurrent treatment effect of diseases, pests and weeds, but also avoid or delay the emergence of drug resistance of harmful organisms, and save the time cost and labor cost of users. However, it is necessary to understand the nature, function and control object of various types of pesticides for mixed use, and scientifically and reasonably mix and use them, rather than mix and use them indiscriminately, otherwise it may not only fail to achieve the purpose of prevention and control, but may even cause serious adverse consequences. For example, when acid pesticides are mixed with alkaline pesticides, it is easy to change the physical properties of pesticides, produce acid-base reactions, cause pesticide degradation failure, and even cause pesticide damage. In addition, when mixing pesticide preparations, attention must be paid to the mixing method (such as mother liquor method or secondary dilution method) and mixing sequence, and clean water should be used as much as possible.

5、 Influence of agent itself

The chemical composition, physical and chemical properties, dosage form, mechanism of action, dosage and processing properties of pesticides directly or indirectly affect the efficacy of pesticides; There will be differences between different dosage forms with the same content of the same ingredient. The production process and production capacity of the preparation of each company are different, and the efficacy of the drug is also very different. In recent years, the rise of precision spray devices such as hot foggers, unmanned aerial vehicles, and electrostatic spray has also put forward higher requirements for the matching use of pesticide preparations.

(Article source: Farmers Daily is only for learning and exchange)