What precautions should be taken when mixing pesticides? Includes a table of pesticides that must not be mixed

Mixing pesticides is a very common pesticide application method nowadays, because the rational mixing of pesticides can improve the control effect, delay the development of pest and disease resistance, improve the control effect, and reduce the amount of pesticide used. Mixing pesticides for controlling different pests and diseases can also reduce the number of applications, thereby lowering labor costs. However, pesticides must be mixed rationally, otherwise it will greatly affect the actual efficacy, and may even be counterproductive.

Precautions for mixing pesticides

OnePesticides whose efficacy decreases after mixing must not be mixedMany insecticides and fungicides easily decompose and become ineffective or have reduced efficacy when mixed with alkaline substances, for example: organophosphorus, carbamate, and pyrethroid insecticides and dithiocarbamate derivative fungicides (thiram, zineb, mancozeb, etc.) decompose under alkaline conditions, so they must not be mixed with alkaline pesticides. These agents should not be mixed with alkaline lime sulfur or Bordeaux mixture. (However, the acaricide hexythiazox has the advantage of being able to be mixed with alkaline pesticides, so it is not included in this list.) Most organic sulfur fungicides are relatively sensitive to acidic reactions, so caution is needed when mixing. For example: shuangxiaoling (that is, copper amino acid) decomposes and releases copper ions when it encounters acid, which not only reduces efficacy but also very easily causes phytotoxicity. Some pesticides cannot be mixed with drugs containing metal ions, for example: thiophanate-methyl, dithiocarbamate fungicides, etc. should not be mixed with copper preparations.

TwoThose that cause phytotoxicity after mixing must not be mixedMixing lime sulfur with Bordeaux mixture; mixing dithiocarbamate fungicides with copper preparations; mixing thiram and dithiane-type fungicides with alkaline drugs,all generate substances that cause serious phytotoxicity to crops, so they must not be mixed.

ThreePesticides with cross-resistance should not be mixedFor example, the fungicides carbendazim and thiophanate-methyl have cross-resistance. Mixing them not only fails to delay the development of resistance in pathogens, but instead accelerates the development of resistance, so they must not be mixed.

FourThose whose physical properties are changed must not be mixedWhen mixing pesticides, pay attention to whether the physical properties of the different components change. Those that produce layering, flocculation and precipitation, emulsion breakdown, reduced suspension rate, or even crystallization after mixing must also not be mixed.When mixing emulsifiable concentrates with aqueous formulations, you can first prepare the aqueous formulation liquid, then use the aqueous formulation liquid to prepare the emulsifiable concentrate liquid. Some acidic aqueous pesticide formulations containing large amounts of inorganic salts will exhibit emulsion breakdown when mixed with emulsifiable concentrate pesticides, and mixing must be prohibited. When organophosphorus wettable powders are mixed with other wettable powders, the suspension rate will decrease, making phytotoxicity likely, so they are not suitable for mixing.

Reference table of pesticides that must not be mixed

(Click the image to see the large version~)

Note:1、X indicates that the two agents cannot be mixed for use. 2、Fluridamide, sodium dichloroisocyanurate, junduqing, maleic hydrazide, etc. can only be used alone.

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