Hormone herbicides still have a lot of 2,4-D and 2 methyl 4 chlorine herbicides
In China, the application history of herbicides is only about 30 years. In the previous manual weeding stage, although it took time and effort, people who had experienced that stage said that the grass at that time was not as powerful as it is now. This is also because although chemical weeding has been implemented for 30 years, weeds in farmland are changing and resistance is increasing, so the corresponding herbicides are changing all the time.
Every year, new products and new active ingredients are launched, but some "old faces" play a role in the market and farmland. Among them, there is a "hormone" herbicide that the author wants to communicate with.
Hormone is transliterated as a hormone, which plays an important role in regulating the metabolism, growth, development and reproduction of living organisms. It is a highly efficient biologically active substance secreted by endocrine glands or endocrine cells, which acts as a messenger in the body to regulate the physiological processes of the body.
Hormone herbicides not only have the effect of weeding, but also have a wider combination of use in crop growth because they have the function of regulating and promoting the physiological functions of plants. When used as a herbicide, these products are more effective and effective, which is also due to their own characteristics. Below we will make a detailed review of several typical hormonal herbicides, analyze their advantages and disadvantages, and facilitate better application.
1, 2, 4-D
2,4-D is a very old product with a chemical name of 2,4-dichlorophenoxyacetic acid, a hormone-selective herbicide with systemic action. The salt preparation is easily absorbed by the plant roots, and the ester preparation is easily absorbed by the leaves. No matter which part is absorbed, 2,4-D will eventually accumulate in the meristematic zone of buds and roots, inhibit plant growth, appear a series of deformed manifestations, and finally die.
As we all know, 2,4-D is just a general term, and its preparations are not only esters, acids, derivatives, but also isooctyl esters. 2,4-D is widely used as an ester. Even now, the northeast market is still widely used to effectively contain the spinach, chicory, and orchid (Amaranthus). Let's take a look at the advantages and disadvantages of each product, the precautions, etc., and hope to help everyone.
2. 2,4-D butyl ester
2,4-D butyl ester, usually used in paddy fields and wheat fields, mainly 57% emulsifiable concentrate, mainly to control dicotyledonous (broad) weeds, heterosexual sage and some malignant weeds, such as ragweed, eyes Vegetables, striata, scorpion, ragweed, wild scorpion, scorpion, etc. It is also used in corn fields and grain fields, but the corresponding drug risk factor is large, so it is more rigorous to use.
2,4-D butyl ester, not only used as a herbicide, when the concentration is lower than 20ppm, it can also play the role of flower preservation and fruit preservation, and has an efficient regulation effect on plant growth, which is why there are some use 2 The use of 4-D butyl ester herbicides in wheat fields has a higher final yield than not being used. At the time of dilution, 2,4-D butyl ester can promote the reproductive growth of wheat and effectively increase wheat tillering.
When the concentration of 2,4-D butyl ester is more than 100ppm, it will hinder the growth of plants, and it has the effect of disturbing the hormone balance in plants, destroying plant conduction tissues and inhibiting photosynthesis. This is the mechanism of action of herbicides. Therefore, its two-sidedness determines that blindly increasing the concentration of the drug will have a negative effect, posing a risk to the safety of the crop itself.
The author has experienced the phenomenon that the use of 2,4-D butyl ester in the wheat field is too late and the concentration is too large, resulting in wheat not heading, or heading malformation and dysplasia.
Figure 1 2,4-D butyl ester applied too late, mild phytotoxic area
At high temperatures, if 2,4-D butyl ester is used in a corn field, the concentration is too large, which can cause the corn leaf leaves to not expand and twist into needle-like growth.
Figure 2 Symptoms of administration of 2,4-D butyl ester corn
The biggest "hazard" of 2,4-D butyl ester is residue and drift. There is no need to elaborate on the drifting. It is the atomized liquid that drifts to the nearby crops with the wind, causing phytotoxicity in neighboring crops. The well-known enterprise that the author knew was not cleaned when the 2,4-D original drug reaction kettle was relocated, and the residual droplets leaked to the road surface, causing large-scale damage to the poplar trees and cotton fields on both sides of the road, and the compensation losses amounted to several million.
In addition, pesticide residues have caused many ordinary people to suffer. A staff member of the 2,4-D original drug production workshop, after cleaning the work clothes many times, went to his home cotton field and went to the cotton field to smell the wind. The author also saw the medicinal damage of cotton, and at first glance determined that the bactericidal damage caused by 2,4-D butyl ester in the nebulizer.
Figure 3 Cotton suffers from 2,4-D butyl ketone symptoms
Northeast corn field for the prevention and treatment of "three dishes", pre-emergence and post-emergence stem and leaf treatment still add 57% 2,4-D butyl ester 500~1000 ml / hectare, but must pay attention to weather factors to avoid phytotoxicity. Due to soil factors, pre-emergence closure of soybean fields in Northeast China should avoid leaching and phytotoxicity. For malignant broad-leaved weeds, chicory, etc., some northeast areas can try to promote 2,4-D and glyphosate mixture, good control effect.
2. 2,4-D isooctyl ester
Herbicidal properties: Selective post-emergence stem and leaf treatment of contact herbicides.
Applicable crops: soybean, corn, wheat.
Control objects: small scorpion, chicory, comfrey, sage, scorpion, scorpion, rice, canary, ramie, ion grass, sorghum, leeks, valerian, Xanthium, sinensis, etc. Or perennial broadleaf weeds.
Control the broadleaf weeds in the wheat field, use 50% emulsifiable concentrate 66~88ml/mu, spray 30~40kg of water on the stems and leaves; control the broadleaf weeds in the corn field, use 50% emulsifiable concentrate 86~122ml/mu before sowing, 30~40kg of water is used for soil spraying; weeds are controlled in soybean fields. After sowing, 50% emulsifiable concentrate is used in 76~90ml/mu, and 30~40kg of water is sprayed on the soil.
2,4-D isooctyl ester appeared from one, more mixed with other products, and better circumvented or reduced many of the shortcomings of 2,4-D butyl ester (such as residue, low temperature resistance, etc. ). The "Mai Shida" of Dow AgroSciences is the most typical representative, and the resistance to the resistance of the wheat field is relatively prominent.
The 2,4-D herbicides have the advantages of relatively low cost and high efficiency, and the target herbicides are not easy to produce resistance. In the concentrated areas of food crops, the residual heat will continue to be exerted under certain circumstances. For example, Maijiagong, which is used to control wheat fields, is the best agent, 2,4-D butyl ester.
2,4-D low temperature resistance is also a must pay attention to avoid the occurrence of phytotoxicity during use. However, the residual wastewater and the wastewater treatment produced by the production of the original drug determine that their longevity will not be long-term. Even if new chemical derivatives appear, everyone should understand the commonality and inferiority of such herbicides, and really make such herbicides work effectively.
2, 2 A 4 chlorine
2 A 4 chlorine chemical name is 2-methyl-4-chlorophenoxyacetic acid, the principle of action is the same as 2,4-D, but the volatility and the speed of action are slightly worse, so in the drift, that is, the surrounding non-target The risk of phytotoxicity of plants is lower than 2,4-D. However, the drug efficacy is poor at low temperatures, especially in the early spring when the temperature of dimethyltetrachlorosodium salt is ≤15 °C, it is easy to cause wheat phytotoxicity.
Wheat field herbicides have transitioned from sulfonylurea single-agent products to sulfonylureas + acesulfame, whereas 2-methyl chloride has been a long-lasting agent for wheat fields. Although in the past two years, due to the unfavorable factors such as good soil moisture and frequent cold after the year, there are more or less problems in compounding or blending products. However, the unavoidable reality is the wheat field herbicide 2A4 chlorine. Using "flooding", from potassium salts, sodium salts, ammonium salts to isooctyl esters, 2 methyl 4 chlorine is also enriching its own family.
The emergence of diflufenacil is the perfect driving of the development of 2, 4, 4 chlorine, diflufenazone + 2 methyl 4 chlorine, like the cornfield, the combination of double swords, will continue to lead the development of wheat field herbicides . Nowadays, the selectivity of weeds in wheat fields is getting stronger and stronger. Manufacturers, sales terminals and ordinary people generally like to co-ordinate the products. It is nothing more than a mixture of drugs or a combination of drugs.
When you use it, you should still understand the weed target of the farmland, minimize the use of unrelated or non-essential agents, and avoid the problem of phytotoxicity caused by the mixing of various agents or the characteristics of the drug during use. Reduce the risk factor.
Figure 4: The field is full of fragrant aconite
After the cornfield herbicide entered the era of nicosulfuron, although nicosulfuron had good control effect on sedge weeds such as fragrant aconite, but after adding 2 to 4 chlorine, it was effectively upgraded, such as Qingdao Jiner “Nongmu†It has created miracles in some areas. Although the appearance of chloropyrimidin has a certain impact on this combination of products, due to the cost-effective, herbicidal spectrum has certain advantages and the improvement of drug technology, such product portfolio will not exit the market.
2 A 4 chlorine, whether in wheat fields, corn fields or paddy fields, safety is slightly higher than 2,4-D products, low temperature resistance is better than 2,4-D products, although active and killing grass The spectrum is slightly lower, but for crops, safety is the first and must be guaranteed. If the 2,4-D category exits the market, the stage of the 2A4 chlorine product may be wider.
2 A 4 chloro + glyphosate, in many cases its advantages surpass paraquat, this combination makes 2 methyl 4 chlorine further sublimation, the quick-acting effect of glyphosate is effectively improved, the herbicidal spectrum is more perfect, in paraquat Withdrawn from the stage, the market for such a mixture still has room for further development when glufosinate and diquat are not completely replaced.
Whether it is potassium salt, sodium salt or ammonium salt, 2 methyl chloride powder or granule dosage form, secondary dilution is very important when used. 2 methyl 4 chlorine is easy to absorb moisture and agglomerate, so it should be avoided.
2 A 4 chlorine is affected by the characteristics of the drug itself and various reasons. Although the amount of acre is increasing year by year and the safety is relatively guaranteed, its low temperature resistance is still a major factor to be considered. The author has experienced a kind of low-temperature wheat, and under the same circumstances, the use of 2 A 4 chlorine causes serious damage.
Figure 5 Wheat suffers from 2 methyl 4 chlorination at low temperatures
There are also some varieties of hormonal herbicides. Because of the low market share and usage, and the uncertain future of development, they are not stated here.
Through the above analysis, you can see:
(1) Hormone herbicides have unique characteristics, rapid effects, clear targets, and significant control effects. This is the biggest advantage of such herbicides.
(2) Hormone herbicides are double-edged swords. The advantages and disadvantages are the same. The disadvantages are as prominent as the advantages. It is the key to control safety.
(3) Hormone herbicides are systemic herbicides, mixed with glyphosate, which makes up for the delisting of paraquat. Although there are some places to pay attention to, it is undeniable to deal with some malignant Grass is still indispensable.
Hormone herbicides are powerful. The author believes that hormonal herbicides will continue to play a greater role in the agricultural arena in the future. I hope that everyone can really make good use of hormone herbicides, so that these herbicides can be made for Chinese agriculture. Greater contribution! (Pesticide market information)
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