A Complete Guide to Pesticide Mixing Principles and Formulation Knowledge

In pest and disease control, single agents are gradually fading from the stage of history. To increase efficacy and achieve the effect of controlling multiple targets at once, the mixing of pesticides has been promoted and applied. The rational mixing of pesticides can improve control efficacy, delay the development of pest and disease resistance, improve control results, and reduce the amount of pesticide used. Mixing pesticides for controlling different pests and diseases can also reduce the number of spray applications, thereby lowering labor costs.

Order of Pesticide Mixing

1. The order of pesticide mixing must be accurate. The usual order for mixing foliar fertilizers with pesticides is: micronutrient fertilizer, water-soluble fertilizer, wettable powder, water-dispersible granule, suspension concentrate, microemulsion, emulsion in water, water, and emulsifiable concentrate added in sequence (in principle, no more than three pesticides should be mixed together). After adding each one, stir thoroughly to mix evenly, then add the next.

2. Add water first, then add the pesticide. When performing secondary dilution mixing, it is recommended to first add more than half a bucket of water to the sprayer, add the first pesticide, and mix well. Then, pre-dilute the remaining pesticide in a plastic bottle, pour the diluted mixture into the sprayer, mix well, and so on (if you want good efficacy, never cut corners).

3. No matter what agents are being mixed, always remember “mix and use immediately, do not leave standing for long.” Although the solution may show no reaction when first mixed, this does not mean it can be left standing for a long time, otherwise slow reactions are likely to occur, gradually reducing efficacy.

Principles of Pesticide Mixing

Mixing pesticides with different toxic mechanisms. Mixing pesticides with different mechanisms of action can improve control efficacy and delay the development of pest and disease resistance.

Mixing pesticides with different toxic effects. Insecticides have modes of action such as contact poisoning, stomach poisoning, fumigation, and systemic action; fungicides have modes of action such as protection, treatment, and systemic action. If these agents with different control effects are mixed, they can complement each other and produce very good control results.

Mixing insecticides that act on different insect stages. Mixing insecticides that act on different insect stages can kill pests at various stages in the field, providing thorough control and thereby improving efficacy.

Mixing pesticides with different durations of effectiveness. Some pesticides have good fast-acting control effects but short residual activity; some have poorer fast-acting efficacy but long-lasting action. Mixing such pesticides not only provides good efficacy after application but also achieves long-term control.

Mixing with synergists. Although synergists have no direct toxic effect on pests and diseases, mixing them with pesticides can improve control efficacy.

Pesticides that act on different pests and diseases. When several pests and diseases occur simultaneously, using this method can reduce the number of spray applications, reduce work time, and thereby improve efficiency.

Precautions for Pesticide Mixing

Although pesticide mixing has many benefits, never mix at random. Unreasonable mixing is not only unhelpful but can produce opposite effects. The following points must be noted when mixing pesticides.

Do not change physical properties

That is, after mixing there must be no floating oil, flocculation, precipitation, or discoloration, and no heat generation or bubble formation. If they are both powders, or both granules, fumigants, or smoke agents, they can generally be mixed;

Between different formulations, such as wettable powders, emulsifiable concentrates, concentrated emulsions, suspension concentrates, aqueous solutions, and other water-based liquid formulations, arbitrary mixing is not advisable.

Do not cause chemical changes

1. This includes that many agents cannot be mixed with alkaline or acidic pesticides. Under alkaline conditions such as Bordeaux mixture and lime sulfur mixture, carbamate and pyrethroid insecticides, and dithiocarbamate fungicides such as thiram and zineb are prone to hydrolysis or complex chemical changes, thereby destroying their original structure.

2. Under acidic conditions, 2,4-D sodium salt, MCPA sodium salt, amitraz, etc. will also decompose, thereby reducing efficacy.

3. In addition to acidity and alkalinity, many pesticide varieties cannot be mixed with agents containing metal ions.

4. Mixing dithiocarbamate fungicides and 2,4-D herbicides with copper formulations can generate copper salts and reduce efficacy.

5. Thiophanate-methyl and thiophanate can complex with copper ions and lose activity.

6. Apart from copper formulations, other formulations containing heavy metal ions such as iron, zinc, manganese, nickel, etc. should be mixed with special caution.

7. Mixing lime sulfur mixture with Bordeaux mixture can produce harmful copper sulfide and also increase the content of soluble copper ions.

8. Propanil, butachlor, etc. cannot be mixed with organophosphorus or carbamate insecticides; some chemical changes may cause phytotoxicity.

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.

Biological pesticides cannot be mixed with fungicides

Many pesticide fungicides have killing effects on biological pesticides; therefore, microbial pesticides and fungicides cannot be mixed.

Shared Pesticide Mixing Formulas

1. Lambda-cyhalothrin + imidacloprid or acetamiprid can prevent green plant bugs.

2. Abamectin + 44% profenofos + chlorpyrifos, used on rice to control rice leaf roller and stem borers, is economical and affordable.

3. Emamectin benzoate + tebufenozide can be used to control noctuid pests, with a long residual period.

4. Thiamethoxam and dinotefuran granules have become new ingredients for preventing small insects.

5. Dinotefuran + lambda-cyhalothrin provides efficient and long-lasting control of whiteflies.

6. Lambda-cyhalothrin + profenofos is a popular formula with special effects against soil-dwelling pests.

7. Emamectin benzoate + triflumuron controls rice leaf roller and fruit tree fruit borers.

8. Emamectin benzoate · monosultap + isocarbophos, an old formula —— targeting various rice pests.

9. Chlorpyrifos + triazophos can prevent rice stem borers (triazophos is prohibited in some areas).

10. Abamectin + chlorantraniliprole + nitenpyram · pymetrozine, a full-spectrum formula for rice.

11. Nitenpyram · pymetrozine + butylcarbamate · imidacloprid/chlorpyrifos has a very good effect on resistant aphids on peach trees.

12. Spirotetramat + abamectin has a very good effect against pear psyllids.

13. Omethoate + fenvalerate has a good effect on killing wheat aphids and the price is not high.

14. Prochloraz + iprodione controls leafy vegetable leaf spots and anthracnose with excellent results.

15. Organic copper formulation + benzoyl prochloraz + iodine solution is economical and affordable for controlling cucumber target spot disease.

16. Abamectin + spirotetramat is absolutely reliable for controlling whiteflies, aphids, and thrips.

17. Emamectin benzoate + chlorfenapyr kills both insects and mites.

18. Buprofezin/chlorpyrifos + spirotetramat resists scale insects, safe and efficient.

19. Dimethomorph + polyoxin · mancozeb controls water spinach white rust and cucurbit downy mildew, drying up spots in three days.

20. Emamectin benzoate · hexaflumuron + cypermethrin controls fruit tree fruit borers with good results.

21. Conventional downy mildew and blight control agents + organic copper formulations increase control efficacy by more than 50%.

22. Flusilazole + organic copper, applied to cucurbit gummy stem blight, gives good healing results.

23. Monosultap + chlorpyrifos has an outstanding effect on killing ginger stem borers.

24. Metalaxyl-M · hymexazol/metalaxyl-M · azoxystrobin + organic copper controls root diseases.

25. Shenqinmycin + Jinglaya treats cucurbit gummy stem blight and Fusarium wilt.

26. Pyridaben + thiamethoxam is outstanding for treating flea beetles.

27. Abamectin + cyromazine controls leafminers.

28. Oxyfluorfen + pendimethalin, for sealing and killing small weeds in garlic fields, controlling both grass and broadleaf weeds, the best combination.

29. Thiamethoxam + bifenthrin, applied as a root drench to control root maggots and Chinese chive maggots.

30. Captan + Bacillus subtilis solves continuous cropping and replanting diseases.

31. Chlorantraniliprole + chlorpyrifos has a very good effect on controlling rice striped stem borer.

32. Emamectin benzoate + tebufenozide has a good effect against beet armyworm and tobacco cutworm.

33. Hydrargaphen + hymexazol/thiophanate-methyl · hymexazol, applied as a root drench to control root diseases.

34. Pyraclostrobin · thifluzamide prevents citrus resin disease (sand papaya disease) with a long residual period.

35. Abamectin + pyridaben/triazotin + bifenazate · Jingzhi treats highly resistant red and white spider mites on fruit trees.