Application Technology for Insecticide Combinations
I. Application Technology for Insecticide Combinations
Combining insecticides is not merely a matter of mixing agents together; it requires scientific and rational formulation based on factors such as application concentration, method of use, and efficacy. The following principles should be strictly observed during formulation:
(i) Synergism Principle: Mixing two or more insecticides can result in either synergistic (enhanced) or antagonistic (reduced) effects. Furthermore, varying the mixing ratios of the same two pesticides alters the degree of their impact. An "additive effect" occurs when the combined toxicity of the mixture against a specific organism equals the sum of the toxicities of the individual components used separately.
(ii) Toxicity Principle: The mixture should not exhibit increased toxicity compared to the individual components; the duration of efficacy should remain the same or increase; and residue levels should not exceed those resulting from the use of the individual agents.
(iii) Phytotoxicity Principle: Some insecticides are safe for crops when used individually but may cause phytotoxicity when mixed; therefore, crop safety must be carefully considered during formulation.
(iv) Resistance Principle: Select pesticide varieties that exhibit negative cross-resistance (where a pest develops resistance to one insecticide but becomes more susceptible to another) or, at the very least, avoid positive cross-resistance (where resistance to one pesticide leads to resistance against another). Generally, pyrethroids do not exhibit cross-resistance with organophosphorus or organonitrogen pesticides and can be mixed.
(v) Acid-Base Reaction Principle: Most insecticides currently used in production are neutral or slightly acidic. They should not be mixed with alkaline pesticides—such as lime-sulfur mixture or Bordeaux mixture—to avoid chemical reactions that could reduce efficacy.
It was first discovered that sesamin (found in sesame oil) acts synergistically with natural pyrethrins; subsequently, various synergists such as piperonyl butoxide (PBO), sulfoxide, MGK 264, and others were developed. These synergists do not possess direct insecticidal activity on their own; however, when added to insecticides, they inhibit the action of oxidative enzymes, preventing the insecticide from breaking down and thereby enhancing its efficacy. Nevertheless, synergists do not boost the effectiveness of all pesticides, and the degree of enhancement varies depending on the specific insecticide used.
Combining insecticides is not merely a matter of mixing agents together; it requires scientific and rational formulation based on factors such as application concentration, method of use, and efficacy. The following principles should be strictly observed during formulation:
(i) Synergism Principle: Mixing two or more insecticides can result in either synergistic (enhanced) or antagonistic (reduced) effects. Furthermore, varying the mixing ratios of the same two pesticides alters the degree of their impact. An "additive effect" occurs when the combined toxicity of the mixture against a specific organism equals the sum of the toxicities of the individual components used separately.
(ii) Toxicity Principle: The mixture should not exhibit increased toxicity compared to the individual components; the duration of efficacy should remain the same or increase; and residue levels should not exceed those resulting from the use of the individual agents.
(iii) Phytotoxicity Principle: Some insecticides are safe for crops when used individually but may cause phytotoxicity when mixed; therefore, crop safety must be carefully considered during formulation.
(iv) Resistance Principle: Select pesticide varieties that exhibit negative cross-resistance (where a pest develops resistance to one insecticide but becomes more susceptible to another) or, at the very least, avoid positive cross-resistance (where resistance to one pesticide leads to resistance against another). Generally, pyrethroids do not exhibit cross-resistance with organophosphorus or organonitrogen pesticides and can be mixed.
(v) Acid-Base Reaction Principle: Most insecticides currently used in production are neutral or slightly acidic. They should not be mixed with alkaline pesticides—such as lime-sulfur mixture or Bordeaux mixture—to avoid chemical reactions that could reduce efficacy.
It was first discovered that sesamin (found in sesame oil) acts synergistically with natural pyrethrins; subsequently, various synergists such as piperonyl butoxide (PBO), sulfoxide, MGK 264, and others were developed. These synergists do not possess direct insecticidal activity on their own; however, when added to insecticides, they inhibit the action of oxidative enzymes, preventing the insecticide from breaking down and thereby enhancing its efficacy. Nevertheless, synergists do not boost the effectiveness of all pesticides, and the degree of enhancement varies depending on the specific insecticide used.
