Don't mix pesticides blindly - remember these three rules

Pesticides are a particular thing, a medicine that follows rules; while killing insects and preventing disease, they must also be used skillfully to play their greatest role, otherwise blindly mixing them on a whim will not only reduce the efficacy but also burn the crops to death. Today, the editor will tell everyone what issues to pay attention to when mixing pesticides!

Organophosphorus, carbamate, and pyrethroid insecticides and dithiocarbamate derivative fungicides (thiram, zineb, mancozeb, etc.) decompose under alkaline conditions, so they cannot be mixed with alkaline pesticides. These agents should not be mixed with alkaline lime sulfur or Bordeaux mixture. (However, the acaricide nissol has the advantage of being mixable with alkaline agents, 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, amino acid copper) decomposes upon contact with acid and precipitates copper ions, which not only reduces efficacy but also very easily causes phytotoxicity. Some pesticides cannot be mixed with drugs containing metal ions, such as thiophanate-methyl and dithiocarbamate fungicides, which should not be mixed with copper preparations.

1. Those that cause phytotoxicity after mixing cannot be mixed

Mixing lime sulfur with Bordeaux mixture; mixing dithiocarbamate fungicides with copper preparations; mixing thiram and disulfiram-type fungicides with alkaline drugs - all will generate substances that cause severe phytotoxicity to crops, so they cannot be mixed.

2. Pesticides with cross-resistance should not be mixed

For 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 cannot be mixed.

3. Those whose physical properties are changed cannot be mixed

When mixing pesticides, pay attention to whether the physical properties of the different components change. If after mixing there is layering, flocculation and precipitation, emulsion breakdown, reduced suspension rate, or even crystal precipitation, they also cannot be mixed. When mixing emulsifiable concentrates and aqueous formulations, 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 show 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, easily causing phytotoxicity, so mixing is not advisable.