Chemical changes in a variety of pesticides have certain chemical properties, in the complex mix of pesticides, if the chemical properties of complex mix of different pesticides, some chemical changes occur. According to their role in biological, chemical changes can be divided into two kinds of beneficial and harmful, to improve the control effect of agents to reduce the toxicity of warm-blooded animals, to reduce injury or some other useful features to increase the chemical change is beneficial. But this situation is the minority, the majority is to reduce the efficacy, increased toxicity and injury. Pesticides should be in the mix as far as possible to avoid adverse chemical reactions, different pesticides have different chemical properties, and thus understand the various types of pesticide chemical changes may occur, considering the complex mix of pesticides is necessary.
The majority of organophosphorus pesticides with acidic, unstable under alkaline conditions, easily decomposed substances without biological activity, loss of control effects. Such as parathion, methyl parathion, fenitrothion, malathion, dimethoate and other pesticides and the rice blast net, net, etc. different rice blast fungicides, pesticides can not and alkaline complex mix. In contrast, phosphorus in alkaline medium bajia stable in acidic medium but break down easily. Carbamate pesticides and organophosphorus pesticides in the same case of failure of alkali break down easily, and basic pesticides should not be mixed compound.
Class of organic sulfur fungicides, dithiocarbamate derivatives, such as Dyson zinc, ziram, thiram and so on, although a certain degree of stability, but also in strong alkaline conditions, decomposition of failure, should not and basic pesticides complex mix.
Trichloro-methylthio basic fungicide containing captan and folpet, although the strong alkaline can also make complex chemical changes occur, but usually is more stable. So they are relatively wide range of complex mix, especially with the mixture of captan large quantities.
The absorption of fungicides such as carbendazim, thiophanate, tricyclazole, which have a certain degree of stability, suitable for mixing with a number of protective fungicides. Phenoxy acid herbicides such as 2,4-D and other chemical properties tend to be more stable, mixed with metallic elements to produce pharmaceutical salt, but generally will not significantly reduce the efficacy in the herbicide agent containing the metal element is less, so its complex mix of relatively wide range.
More complex nature of plant pesticides in general and organic synthesis of pharmaceutical compound can not afford much when you mix chemistry, little effect on the agents. Complex mix of various types of pesticides, the most vulnerable to chemical reaction, reduce the efficacy, there is phytotoxicity of inorganic pesticides. Inorganic pesticides, basic chemicals and pesticides in the most metal elements, which in the complex mix of the most vulnerable to failure of other pesticides break down, or produce injury. Thus, for two or mixtures of several pesticides are mixed and must be confirmed by experiment. Changes in the physical mixtures of pesticides should be noted first of all whether the changes in physical properties. Complex mix of pesticides after physical changes of no more than three ways.
(1) pesticides complex mix, the physical properties did not change basically, to keep with the original formulation of the physical properties. And thus will not affect the control effect, it will not happen injury, such agents can be considered a mixed compound.
(2) improved after the pesticide compound physical properties of formulations to improve the control effect of Pharmacy. If Dan herbicide propanil and mixture of EC is not prone to crystallization, emulsification properties, thereby enhancing the efficacy
(3) pesticide compound after a bad physical changes, such as the EC demulsification; poor dispersion of various formulations; WP suspension reduced; Xu Results or precipitation, so that a good agent lost its original physical properties, reduce the control efficacy, it might even cause injury. Adduct with the efficiency of pesticide mixtures of two or several together, the biological (including the prevention and control objects, protected objects, people and livestock, etc.) are likely to enhance the role.
(1) strengthen co-operation with a complex mix of biological pesticides on the virulence of the same composition of the mixture with a variety of pharmaceutical toxicity alone is equal to the sum of the combined effects of belonging to strengthen co-operation, also is the additive effect. Such as carbaryl and culling Wei 1Η1 complex mixture of confrontation and black-tailed leafhopper is a typical example. In general, the chemical structure is similar to the same mechanism of action of pesticide mixtures together and strengthen co-operation shown by the majority. As quick result, residual activity, ovicidal activity, biological activity spectrum and price differences, with certain pharmaceutical compound, the toxicity test results, while the performance of co-operation with Canada, but can learn from each other in the performance, there is a practical value. Such as carbaryl - speed off powder, mites ester - mites alcohol WP.
(2) increasing efficiency or toxicity of a mixture of biological agents on the virulence of the same than in the pharmaceutical composition of the mixture toxicity of single-dose and large, their combined effect in the case of synergies, synergies with this changes in the ratio changes. Such as benzene parathion, net, etc. on the decomposition of rice blast malathion carboxylic acid ester has high inhibition, so that the biological toxicity can be strengthened. Another example is the herbicide propanil or herbicides, or the spiritual and organic phosphorus compound carbamate insecticides mixed rice injury when the level of increase; eliminate mites and Diazinon EC Meng and pharmaceutical mix phytotoxicity of apple trees ; Captafol and the EC pharmaceutical mix of citrus trees produce injury; more fruit set increased with the EC pharmaceutical mix of injury to pear.
In general, a separate application prone to injury pharmacy mix of pharmaceutical and EC, increased injury. Antagonism of the same complex mixture on the virulence of a biological agent than the pharmaceutical composition of mixed virulence alone and significantly lower, it is called antagonism. Antagonistic effect in the fight against the performance of lower body injury protection to reduce the object table. Such as diclofop-methyl and 2,4-D, mixed cresol dinitro reduced diclofop when the control effect on wild oat; multi-element oxygen neomycin and blast off mix, lower and more oxygen ADM on rice sheath blight control effect. Antagonism to reduce injury to the protected object also has many examples, such as zinc sulfate and maneb mix, can reduce the injury maneb. Preparation of copper and streptomycin mix, reducing the phytotoxicity of streptomycin on the cabbage. Trifluralin - Metribuzin Metribuzin mix reduced the phytotoxicity of soybean. Use of these antagonistic effects, can expand the scope of application of pharmaceutical
A mixture of a control object is the best, but not necessarily ideal for another control object. Such as zinc mixture of carbendazim and Dyson have synergistic effect on grape gray mold, powdery mildew on melons only strengthen co-operation with the performance.
A mixture of the control object is efficiency, and on the protected object does not increase the injury, why is it possible to use mixtures of different pesticides on biological efficiency, increase cooperation or antagonism, selected ideal for efficient and safe drug, and has new features, and become a new pesticide. Complex mixture of pesticides is a complex, if mix is unreasonable, many adverse consequences that may arise, resulting in the loss, it is necessary to promote a reasonable mix, without a comprehensive test of the complex program it should not be promoted.
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