Principles and matters needing attention in the mixed use of pesticides in "remembering Agriculture and Pesticide"

The mixed application of two or more pesticides in the field is called the mixed use of pesticides. Now in agricultural production, most farmers will mix pesticides. However, if you do not understand the characteristics of pesticides, pesticides mixed together will reduce the efficacy and even cause harm.

Advantages of mixed use of pesticides

First, enhance the effect of prevention and control.

It can treat two or more simultaneous diseases, insects and weeds during the crop growth period in one application, so that repeated field operations can be completed at one time, labor can be saved, and prevention and control can be done in time.

Second, one-time use of drugs has multiple effects.

The mixed use of pesticides can expand the scope of control, learn from each other, improve imitation or prolong the residual period.

Third, to some extent, it overcomes the drug resistance of pathogenic bacteria and prolongs the drug resistance.

The mixed use of pesticides can prevent and overcome the resistance of pests and prolong the service life of pesticide varieties.

Fourth, it can improve the hit rate of unknown diseases.

5. The mixed use of some new and old drugs can greatly prolong the service life of old pesticides.

6. The mixed use of some imported pesticides and domestic pesticides can not only improve the efficacy, but also reduce the dosage of pesticides, thus reducing the cost. It can also reduce environmental pollution and harm to natural enemies.

Principles of mixed use of pesticides

When mixing pesticides, bad chemical reactions should be avoided as far as possible, and different pesticides have different chemical properties, so it is necessary to understand the possible chemical changes of all kinds of pesticides. When mixing pesticides reasonably, we should pay attention to the following points.

First, the chemical stability of the active ingredients should not be affected.

In the mixed use of pesticides, there is no adverse chemical reaction (such as hydrolysis, alkaline hydrolysis, acidolysis or redox reaction, etc.), which ensures the normal efficacy or efficiency, and does not affect the physical properties of the agent (such as emulsification, suspension rate reduction, etc.).

Organophosphorus and carbamate pesticides are sensitive to alkaline pesticides. Pyrethroid insecticides and dithioamino fungicides can also be decomposed under strong alkaline conditions.

After the mixed use of acid pesticide and alkaline pesticide, complex chemical changes will take place and destroy its effective components.

Second, the physical properties of the agent should not be destroyed.

The mixture of two kinds of EC is still required to have good emulsification, dispersibility and wettability.

The mixed use of two kinds of wettable powder requires good suspension rate and wettability. This is not only a condition to exert its efficacy, but also to prevent failure, reduction of efficacy or drug damage due to changes in physical properties.

Powder should not be mixed with wettable powder and soluble powder.

In the mixed use of all kinds of pesticides, inorganic pesticides are the most prone to chemical reactions, reduce efficacy and harm. Among the inorganic pesticides, alkaline pesticides and pesticides containing metal elements are the most common, and they are most likely to break down or cause drug damage in the mixed use of other pesticides.

Third, the mixed use of different varieties can not cause drug damage to crops.

The mixture of organophosphorus insecticides and paspalum will cause drug damage to rice, and the mixture of Bordeaux solution and stone sulfur mixture can easily cause drug damage to crops.

Fourth, the mixed pesticides will not increase the toxicity and ensure the safety to human beings and animals.

The mix should be reasonable. Including the reasonable collocation among varieties, such as the control of Gramineae weeds in soybean field, it can be controlled only by catching and stamping. Although the mixture of the two is feasible in terms of chemical stability, it is unreasonable and does not increase efficiency and expand the scope of control. Mixed use is not necessary.

Fifth, pay attention to the antagonistic effect of pesticide varieties to ensure the effect of mixed use, such as bentazone and nachujing reduce the control effect of Gramineae weeds because of antagonistic effect.

Sixth, the mixed price of pesticides should be reasonable.

In order to save labor and time and improve economic benefits, the mixed use of pesticides should generally be lower than the monthly cost. For the same control object, the mixed use of pesticides with high cost and low cost often has obvious economic benefits as long as there is no resistance. The cost of mixing more expensive new internal absorption fungicides with cheaper protective fungicides and pyrethroids pesticides with organophosphorus insecticides is lower than that of single use. If the mixture is made, the additional cost is very high and can not be allowed.

7. Pay attention to the scope of use of mixed medicament.

There is not only a relationship but also a difference between the scope of use of mixed pesticides and the range of use of various active ingredients contained in single agents. mixed pesticides must have their own characteristics in the scope of use, so that mixed pesticides can be effective.