First, the principle of mixing pesticides
There are many advantages to mixing pesticides, but it is not that all pesticides can be mixed, and not all pesticides need to be mixed. Mixed use is strictly required, and it must be judged whether it can be mixed or mixed according to the chemical and physical properties of the drug itself, as well as the laws and life history of the pests and diseases. Whether the various pesticides can be mixed with each other should generally consider the following aspects:
1. It is necessary to clarify the purpose of the mixed use of pesticides: the mixed use of pesticides should mainly achieve the purpose of increasing efficiency, treating and expanding the scope of prevention and control. If you can't achieve the above purpose, it should not be mixed, otherwise it will cause waste, not get the effect it deserves, and even cause phytotoxicity.
2. No adverse chemical and physical changes should occur after the pesticide is mixed: if the agent is not decomposed after mixing, the emulsifiable concentrate is not destroyed, and the suspension does not produce flocculation or a large amount of precipitation. A large number of pesticides , fungicides and herbicides quickly decompose and fail when exposed to alkaline substances. Any agent that is easily decomposed under alkaline conditions cannot be mixed with alkaline substances.
3. No phytotoxicity after mixing: After mixing, the mixed liquid should not cause phytotoxicity on crops. If phytotoxicity occurs, it cannot be mixed with each other.
4, after mixing, to increase efficiency: after mixing the drug, it should improve the efficacy of the mixed liquid, at least should not reduce the efficacy, that is, after mixing to increase efficiency.
5. Toxicity is not enhanced after mixing: After mixing the agents, the acute toxicity of the mixture is generally not higher than the original toxicity, that is, it cannot be poisoned.
6. Strict use concentration: Some people mix 1000 times of the drug with 1000 times of the drug, and then mix it together. It is used as the A and B drugs of 1000. In fact, the dilution of the two pesticides A and B is mixed. The multiple is not 1000 times, but 2000 times. It should include 1 part of the medicine and 1 part of the medicine in the amount of water required to be 1000 times. Such as: 50 kg of water plus 50 g of nail medicine and 50 g of medicine, it is 1000 times a mixture of A and B.
7. Strictly harvested according to the safety interval: The safety interval refers to the number of days after the last application of a certain pesticide on the crop as specified in the pesticide safety use standard, mainly to ensure that the pesticide residue can be reduced to the allowable level at the time of harvest. Below the content. Therefore, the use of pesticides is prohibited for a period of time before the harvesting of tobacco. If the area of ​​tobacco pests and diseases is large, and it is really necessary to spray pesticides, the harvesting time of tobacco should be extended to reach a safe interval.
Second, the principle of mixing pesticides and fertilizers
1. After mixing, the original physical and chemical properties can be maintained, and the fertilizer effect, drug effect and hormone can be exerted.
2. No chemical reactions such as acid-base neutralization, precipitation, salting out, etc. occur between the mixtures.
3. The mixture will not cause toxic effects on crops.
4. The components in the mixture are consistent in the efficacy time, application site and use object, and can fully exert their respective effects.
5. If you are not sure, you can test it in a small area and mix it when it proves that there is no adverse effect.
Third, several factors need to be mastered to improve the synergy of pesticides
1. Different mechanism of action: Pesticides will synergistically increase each other, especially those with different mechanisms of action, and the synergy is more significant, thus improving the control effect.
2, the speed of drug efficacy is not the same: the speed of the two pesticides is not the same, if the rational mix, you can complement each other. For example, avermectin is mixed with beta-cypermethrin, the former is slow to kill insects, and the latter is fast in killing insects, which can accelerate insecticidal action after compounding. If the protective fungicide is slow in effect, the therapeutic fungicide has a quick effect, and the therapeutic fungicide is usually mixed with a protective fungicide, such as: a cream; manganese zinc.
3. Expanding the spectrum of prevention and control: Some pesticides have a good killing effect on lepidopteran pests, but they are not effective against mites. If it is mixed with a strong killing insecticide or a strong acaricide or acaricide , it can simultaneously control lepidopteran pests and mites. A multi-purpose medicine can save labor and time. For example: Avi Lingling. The combination of Hecao Ling and Isoproturon can improve the control effect on wild oats and broadleaf grass; the combination of paraquat and metformin can expand the range of grass killing.
4. Delaying drug resistance: Pyrethroid pesticides are compounded with various organophosphate insecticides, which have synergistic effects and can delay the development of resistance of pests.
5. Addition of active ingredients: When many pesticides are mixed, each component has a synergistic effect. For example, difenoconazole and propiconazole. Dimethoate neutral and acid bactericidal properties such as zinc, wet sulphur, colloidal sulfur, etc., the effect is not affected, but slightly improved.
Fourth, the precautions for mixing pesticides
1. pH is an important factor affecting the effectiveness of each component. Under alkaline conditions, dithiocarbamate fungicides such as carbamate, pyrethroid insecticides, thiram, and dexame ring are prone to hydrolysis or complex chemical changes, thereby destroying the original structure. Under acidic conditions, 2.4-D sodium salt, 2 potassium 4 sodium chloride salt, amitraz and the like are decomposed, thereby reducing the efficacy. Some pesticides will decompose in the presence of alkaline substances, such as organophosphorus pesticides. If the agents mixed with them are alkaline, they will be less effective, so not all pesticides will be synergistic. Some farmers' friends often take several insecticides and use them together in the field. This method of operation is not appropriate and should be used.
2. Organic sulfur and organophosphorus pesticides cannot be mixed with pesticides containing copper preparations. For example, a dithiocarbamate fungicide, a 2.4-D salt herbicide, and a copper formulation are inactivated by binding to copper ions.
3. Microbial insecticides and systemic organophosphorus pesticides cannot be mixed with fungicides.
4. Mixed use of emulsifiable concentrate and wettable powder requires no delamination, oil slick, precipitation and the like.
5, should avoid the phytotoxicity of the mixture, chemical changes in the composition of the mixture can produce phytotoxicity, such as stone sulphur mixture mixed with Bordeaux mixture can produce harmful copper sulphide, will also increase the content of soluble copper ions, enemy, diced grass Amines and the like cannot be mixed with organic phosphorus or carbamate insecticides.
5. Precautions for mixing fertilizers, pesticides and regulators
1. Alkaline pesticides such as Bordeaux mixture, stone sulphur mixture and rosin mixture cannot be mixed with ammonium nitrogen fertilizer and ammonium superphosphate such as ammonium carbonate, ammonium sulfate, ammonium nitrate or ammonium chloride, otherwise ammonium volatilization or precipitation may occur. Reduce fertilizer efficiency.
2. Alkaline fertilizers such as ammonia, lime, and plant ash cannot be mixed with pesticides such as trichlorfon, acesulfame, thiophanate, jinggangmycin, carbendazim, leaf mites, and pyrethroid insecticides. Because most organophosphorus pesticides will decompose and fail under alkaline conditions.
3, the fertilizer can not be mixed with the microbial pesticide, chemical fertilizers because volatile, corrosive, and if microbial pesticides such as fenitrothion bacteria, bacteria mix caterpillar, easy to kill microorganisms and reduce the control effect.
4, arsenic-containing pesticides can not be mixed with potassium salts, sodium salts, etc., such as calcium arsenate, aluminum arsenate, such as potassium salts, sodium salts mixed will produce soluble arsenic, resulting in phytotoxicity. In all the mixed use of fertilizers, the most mixed fertilizers and herbicides, followed by pesticides, and less fungicides.
6. Precautions for mixing fertilizer and fertilizer
1. Superphosphate cannot be mixed with alkaline fertilizers such as grass ash, lime nitrogen and lime, otherwise it will reduce the effectiveness of phosphorus; phosphate phosphate, bone powder and other insoluble phosphate fertilizers cannot be mixed with alkaline fertilizers such as grass ash, lime nitrogen and lime. Otherwise, because the organic acid in the soil is neutralized, the poorly soluble phosphate fertilizer is more difficult to dissolve, and the crop cannot be absorbed and utilized.
2. Alkaline fertilizers such as calcium, magnesium and phosphate fertilizers cannot be mixed with ammonium nitrogen fertilizers, because alkaline fertilizers, if mixed with ammonium nitrogen fertilizers, will increase ammonium volatilization.
3. Chemical fertilizers cannot be mixed with bacterial fertilizers because they have strong water absorption, corrosiveness and volatility. If mixed with bacterial microorganisms such as rhizobium, they will kill or inhibit live bacteria and invalidate bacterial fertilizers.
7. Interaction between pesticides and fertilizers
1, insecticide, acaricide and fertilizer mixed
(1) Insecticides have many effects on plant mineral nutrition. Production practices have proven that many chlorinated hydrocarbons, organophosphorus and carbamate pesticides can affect plant growth and mineral nutrition. In the study of the mixed effects of different nitrogen fertilizers and nematicides on cotton, nematicides significantly promoted cotton growth, increased yield and increased nitrogen and potassium content in cotton leaves; aldicarb was more effective than chlorpyrifos. The ratio of nematicidal agent to nitrogen fertilizer alone, nematicidal agent combined with nitrogen fertilizer (ammonium nitrate, ammonium sulfate, urea), cotton plant height, total peach per plant, plant dry weight and nitrogen and phosphorus content in leaves There has been a significant increase.
(2) The effect of fertilizers on pesticides. The combination of nitrogen, phosphorus and potassium fertilizers with pesticides may improve the surface activity of some pesticides, increase their permeability and adhesion, and thus increase their insecticidal activity. For some trace elements, it may react with different insecticides to increase or decrease their activity.
Some fertilizers can also be used as insecticides and fungicides. For example, Russians use ammonium nitrate as a nematicide to prevent and control soil nematodes and reduce environmental pollution caused by the application of pesticides.
Improvement of plant nutrition will also increase its resistance to pests. There is usually a positive correlation between nitrogen application and pest invasion, but a large amount of potassium fertilizer can reduce the invasion of insects. Sugar, amino acids and amides in plants are the feeding stimuli of most sucking insects. Changes in mineral nutrition of plants can affect the changes of these substances. Fertilization can adjust the accumulation of these low molecular organic compounds or can be used as insect repellent. The reduction of the compound has an effect on the insect resistance of the plant.
The deposition of mineral elemental silicon in plant epidermal cells is also a mechanical barrier to the needles of sucking insects, especially the upper jaw of chewing insects. Application of silicone in combination with insecticides in some silicon-deficient areas will enhance the efficacy of pesticides. . Reasonable mixing of pesticides and fertilizers can improve the insect-resistant ability of plants by increasing the penetration, absorption and conduction of pesticides in plants and pests, thereby improving the control effect and reducing the amount of pesticides.
2. Mixture of fungicide and fertilizer
(1) The effect of fungicides on plant mineral nutrition. The application of fungicides can also have a certain impact on plant mineral nutrition. Captan, thiram, pentachloronitrobenzene, dikesson, mancozeb, etc. can reduce the absorption of manganese by corn, increase the absorption of zinc, and increase the fresh weight of plants. Foliar application of carbendazim, methyl thiophanate, dexamethasone and thiram added increased nitrogen content in peanut leaves, and methyl thiophanate and carbendazim had the greatest increase in nitrogen; and methyl thiophanate, The application of carbendazim, high concentration of zinc and thiram also increased the content of phosphorus and potassium in the leaves.
(2) Effects of fertilizers and plant nutrition on pesticides. Fertilization often leads to an increase or decrease in the disease resistance of plants, thereby affecting the disease prevention effect of the fungicide. Spraying the fungicide propiconazole and urea mixture in wheat production increases the absorption of propiconazole in wheat due to the high leaf activity of urea and the high photosynthetic rate of crops after propiconazole and urea.
3. Mixing of herbicides and fertilizers
(1) The effect of mixed use on crop yield In the mixed use of pesticides and fertilizers, the combination of herbicides and fertilizers is the most studied, and the practice and application are also the most.
(2) The effect of fertilizer on herbicides, liquid fertilizer urea or ammonium sulfate mixed with glyphosate also increased the herbicidal activity of glyphosate.
(3) The effects of herbicides on plant mineral nutrition, different herbicides have different performances, and chlorpyrifos can promote mineralization and nitrification. In the case of high doses, chlordron also increases mineralization in soil. Nitrogen content. The application of phosphate fertilizer and potassium fertilizer can relieve the inhibition of corn growth by trifluralin, significantly increase the dry weight of plants and the content of phosphorus and potassium in the body, and decrease the content of magnesium and calcium.
Eight, the synergy of pesticides and other additives
When controlling crop diseases, pests and weeds, a small amount of vegetable oil, or mineral oil, or white sugar, or washing powder and salt equivalent pesticides can be mixed to significantly improve the efficacy and enhance the control effect.
1, Bordeaux mixture plus sugar to prevent precipitation. Bordeaux mixture is a fungicide for controlling a variety of crop diseases. Fruit trees and vegetables downy mildew, anthracnose, ulcer disease, etc. have good control effects, and are widely used in production. However, the outstanding problem in use is that the precipitation is fast, and it is easy to produce phytotoxicity after a little careless use. After the test, it was better to add white sugar to the Bordeaux mixture. The precipitation occurred after 15-20 minutes without the addition of white sugar, and no precipitation occurred when the Bordeaux mixture with white sugar was placed for 12 hours. The specific method is as follows: When preparing Bordeaux mixture, try to use high-quality quicklime and copper sulfate, and prepare according to the needs, then add 1 kg of white sugar per 100 kg of the prepared solution, and mix well. In this way, the stability of the Bordeaux mixture can be significantly improved, and after the sugar is absorbed by the crop, it is more effective in preventing diseases.
2, stone sulfur mixture plus washing powder and salt effect is good. Stone sulphur mixture is a commonly used special agent for controlling fruit tree leaf shrinking disease, powdery mildew, ring rot, pear rust, flower rot, rust and various mites, but the egg killing effect is not ideal, especially the stone sulphur mixture is used alone. The control of citrus red spiders decreased by 87%, 85%, and 39% after 1, 2, and 7 weeks, respectively. The technical staff of the Longhuahua Orchard in Lingguan Town, Jidong County, Hunan Province, used the method of adding washing powder and salt to the stone sulphur mixture, which can reduce the insect mitigation rate in the first, second and seventh weeks to 99%-100%. Their approach is: add 0.5% washing powder and 0.4% salt to 0.5-wave meto-sulfur mixture, mix well and spray. Dissolve the washing powder and salt completely before use, then mix well with the stone sulphur mixture and use it with your equipment. When spraying, the front and back sides of the blade should be sprayed evenly, and the effect is quite good.
3. Add vegetable oil to the pesticide. After blending vegetable oil such as cottonseed oil, rapeseed oil and soybean oil with pesticides, vegetable oil can not only play the role of oil-based surface activation, but also be a good anti-volatile agent, which can evenly cover the sprayed liquid. On the surface of plants, and to ensure that pesticides have a longer residual period. Among the synthetic pyrethroid pesticides, vegetable oil is also a good diluent. Use it as an adjuvant to avoid phytotoxicity to certain sensitive crops due to the use of mineral oil. When vegetable oil is mixed with pesticides, it can produce good permeability, increase the coverage of plants, is not easily washed away by rain, and maintain good efficacy after rain. Vegetable oil mixed with pesticides also has the characteristics of photolysis, which can reduce the strong drift during spraying and overcome the shortage of water due to minerals and reduce the active ingredients of pesticides. Vegetable oil is highly viscous and is ideal for low volume sprays and ultra low volume sprays. Studies have shown that using vegetable oil as an adjuvant spray can reduce the dose by 1/8 or more.
It is worth noting that although vegetable oil and pesticides are mixed, although vegetable oil can not be mixed too much, in order to prevent the nozzle from clogging due to excessive foam.
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