Herbicides can effectively and quickly control farmland weeds. In recent years, the application rate and application area have been continuously expanded, and the effect is remarkable. However, when it is used, it often causes various phytotoxics in crops due to improper application, causing serious losses. In order to prevent and overcome phytotoxicity, attention should be paid to the diagnosis and use of herbicides.
First, the symptoms of phytotoxicity. The symptoms of phytotoxicity caused by herbicides are variability and diversity. Similar to the symptoms of certain diseases, they often cause misunderstandings in diagnosis. The general phytotoxicity is faster than the disease symptoms, and no pathogens appear. The identification of herbicide phytotoxicity should be strengthened in production.
(1) Phenoxycarboxylic acids: commonly used agents are 2,4-D, dimethyltetrachloride, 2,4-butyl butyl ester and the like.
Symptoms are leaf, flower, and ear deformity. Leaves thick, thick green, curly, chicken-claw or onion tubular; stems brittle, fragile, swollen stem; roots short and thick, no root hair, short plants; stop growing in severe cases, cortical cracking, falling flowers, fruit falling, and finally death .
(B) aryloxyphenoxypropionic acid: commonly used agents have a stable kill, grass, grass, canopy, weima, Hummer and so on.
Symptoms are mainly plant malformations, the growth point turns yellowish brown, and the heart leaves are purple or yellow.
(3) Diphenyl ethers: Commonly used agents are herbicides, weeds, and tigers.
Symptoms are brown necrotic spots on the leaves, severe leaf deformities, dry coke, and no new leaves.
(4) Amides: commonly used agents include cable, dur, propanil, butachlor and the like.
Symptoms are light yellow leaves, heavy spots appear spots, curled and shrunk, and finally die.
(5) Carbamates: Commonly used agents are herbicides, herbicides, oats and so on.
Symptoms are leaf curl, many tillers, stem base, new roots are short and short, and plants are short.
(6) Substituting ureas and trichlorobenzenes: mainly green merlon, chlorpyrifos, simazine and so on.
Mainly for chlorosis, heart and leaf tips, yellowing like fire, short plants, slow growth.
(7) Heterocyclics: mainly paraquat, glyphosate, Bean Kewei, oxacillin, and bentazon.
Symptoms are leaf discoloration, yellowing, and finally the plants die.
Second, the prevention of phytotoxicity. In order to prevent the use of herbicides from improper use, it is necessary to strictly follow the use of technology and standard operation.
(1) Pay attention to herbicides and sensitive crops. Different crops are not sensitive to different herbicides. Herbicides that control broadleaf weeds are sensitive to grass crops, while broadleaf crops are sensitive to herbicides that control grass weeds. Such as 2,
4-drip, dimethyltetrachloride is sensitive to cotton, melons, beans, fruit trees, etc.; grass cover, stable kill, etc. are sensitive to wheat, rice, and corn. Therefore, when using, be optimistic about the instructions, recognize the characteristics and performance of the herbicide, pay attention to sensitive crops, beware of misuse or drug drift.
(2) Pay attention to the sensitive period of crops. Under normal conditions, crops are particularly sensitive to herbicides during germination, pre-three-leaf and flower-filling, and are prone to phytotoxicity.
(3) Strictly control the amount and concentration of herbicides. In order to prevent the local phytotoxicity caused by the high dosage and concentration of the herbicide, when the herbicide is used, the liquid should be sprayed evenly, the walking speed, the width and width of the manual control spray, the speed should be uniform, and the working time is not too long.
(4) Mastering the operational points of herbicide use technology
1, "one flat": the ground should be flat. The field of application should be finely cultivated to ensure that the ground is flat, no large clods, no pits.
2, "two uniform": the drug should be evenly mixed on the carrier, spray or toxic soil should be even.
3, "San Zhun": the timing of application, the amount of application, the area of ​​the application of the plot. For example, 40% oatmeal is used to control wild oats, and 3 kg/ha is used before sowing.
4, "four look": look at the seedlings, grass, weather, soil quality. It is not easy to apply to unrooted or thin seedlings: according to the type and growth of weeds; when the temperature is low, the application rate is the upper limit; the weight of the soil is higher, the amount of sandy soil is less; the soil is dry. No medicine.
5, "five no": seedlings weak seedlings do not apply medicine; paddy field water is less than 3 cm or water depth flooded heart leaves do not apply; field soil is too dry to apply; when there is heavy rain or when there is dew on the leaves, do not apply; No rice is applied in the paddy field.
(5) Master the performance of the drug. Master whether the agent is volatile, photolyzed, and susceptible to physical or chemical reactions in the soil.
(6) Defining the “main attack locationâ€. In general, the herbicide "main attack site" of soil treatment is the part of weeds that has just sprouted, young stems and leaves, that is, before 3 leaves. Sulfosin is treated as stems and leaves at the weed stage, absorbed by stems and leaves and then transmitted to other tissues.
(7) The time of administration is reasonable. If the enemy is in the 2 leaf stage, the butachlor is 2-3 days before sowing, and the trace of glyphosate increases with the increase of the leaf area of ​​the weed.
(8) Play the role of water. Xicaojing, Guoer, Hedazhuang, Nongde, etc., keep the water layer 4-6 cm after application, can exert the effect of the drug, and no phytotoxicity; while the herbicide and herbicide ether are easy to accumulate in the field. Produce phytotoxicity.
(9) Prohibition of chaos and confusion. Mixture of herbicides can improve the efficacy and expand the spectrum of killing grass, but blindly mixed, easy to cause phytotoxicity. If the enemy can not be mixed with organophosphorus or carbamate; xyltetrachloride can not be mixed with acidic pesticides.
(10) Cleaning spray equipment. The sprayer that has used the herbicide should be cleaned first, then rinsed with water first, then repeatedly with soapy water or 2-3% alkaline water, and finally rinsed with water.
Third, the remedy of the drug. Once herbicides are used to cause phytotoxicity, effective measures should be taken to remedy and minimize possible losses.
(1) Detoxification: (1) When the drug is used the most, the field irrigation water should be drained immediately, washed with new water several times, and neutralized with acidic herbicides such as lime. (2) If there are many herbicides on the plant, it can be rinsed with sprinkler mechanical water to reduce the poison attached to the leaves. (3) When local phytotoxicity occurs in the field, first rinse the water, cultivate, and then replenish the seedlings, and then add quick-acting fertilizer. (4) If the field is poisoned seriously, the plot should be exposed to the sun, deep-washed after leaching, and then planted without affection, otherwise it will be re-irrigated. Or plant a small amount of sensitive crops and observe for 10-15 days.
(2) Strengthening field management. When the phytotoxicity is light, timely topping or removing the affected part, adding quick-acting fertilizer and rational irrigation; when severe, ploughing the land, replanting or replanting; when the cystic leaves are found in the grass, more fertilizer can be applied. Organic fertilizer can also be sprayed with dilute ammonia or 1% lime water and sprayed with hormone pesticides.
(3) Application of plant growth regulators. Spray 4% gibberellin EC to promote crop growth.
(4) Application of safety agents. Safeners, also known as antidotes, protect crops and detoxify a variety of herbicides. If the seeds are coated with activated carbon or roots, stalks, or evenly spread on the soil surface, simazine can be prevented from causing phytotoxicity to soybeans and wheat; guanidine phthalic anhydride can prevent sulfides such as acetaminophen against corn. The phytotoxicity.
First, the symptoms of phytotoxicity. The symptoms of phytotoxicity caused by herbicides are variability and diversity. Similar to the symptoms of certain diseases, they often cause misunderstandings in diagnosis. The general phytotoxicity is faster than the disease symptoms, and no pathogens appear. The identification of herbicide phytotoxicity should be strengthened in production.
(1) Phenoxycarboxylic acids: commonly used agents are 2,4-D, dimethyltetrachloride, 2,4-butyl butyl ester and the like.
Symptoms are leaf, flower, and ear deformity. Leaves thick, thick green, curly, chicken-claw or onion tubular; stems brittle, fragile, swollen stem; roots short and thick, no root hair, short plants; stop growing in severe cases, cortical cracking, falling flowers, fruit falling, and finally death .
(B) aryloxyphenoxypropionic acid: commonly used agents have a stable kill, grass, grass, canopy, weima, Hummer and so on.
Symptoms are mainly plant malformations, the growth point turns yellowish brown, and the heart leaves are purple or yellow.
(3) Diphenyl ethers: Commonly used agents are herbicides, weeds, and tigers.
Symptoms are brown necrotic spots on the leaves, severe leaf deformities, dry coke, and no new leaves.
(4) Amides: commonly used agents include cable, dur, propanil, butachlor and the like.
Symptoms are light yellow leaves, heavy spots appear spots, curled and shrunk, and finally die.
(5) Carbamates: Commonly used agents are herbicides, herbicides, oats and so on.
Symptoms are leaf curl, many tillers, stem base, new roots are short and short, and plants are short.
(6) Substituting ureas and trichlorobenzenes: mainly green merlon, chlorpyrifos, simazine and so on.
Mainly for chlorosis, heart and leaf tips, yellowing like fire, short plants, slow growth.
(7) Heterocyclics: mainly paraquat, glyphosate, Bean Kewei, oxacillin, and bentazon.
Symptoms are leaf discoloration, yellowing, and finally the plants die.
Second, the prevention of phytotoxicity. In order to prevent the use of herbicides from improper use, it is necessary to strictly follow the use of technology and standard operation.
(1) Pay attention to herbicides and sensitive crops. Different crops are not sensitive to different herbicides. Herbicides that control broadleaf weeds are sensitive to grass crops, while broadleaf crops are sensitive to herbicides that control grass weeds. Such as 2,
4-drip, dimethyltetrachloride is sensitive to cotton, melons, beans, fruit trees, etc.; grass cover, stable kill, etc. are sensitive to wheat, rice, and corn. Therefore, when using, be optimistic about the instructions, recognize the characteristics and performance of the herbicide, pay attention to sensitive crops, beware of misuse or drug drift.
(2) Pay attention to the sensitive period of crops. Under normal conditions, crops are particularly sensitive to herbicides during germination, pre-three-leaf and flower-filling, and are prone to phytotoxicity.
(3) Strictly control the amount and concentration of herbicides. In order to prevent the local phytotoxicity caused by the high dosage and concentration of the herbicide, when the herbicide is used, the liquid should be sprayed evenly, the walking speed, the width and width of the manual control spray, the speed should be uniform, and the working time is not too long.
(4) Mastering the operational points of herbicide use technology
1, "one flat": the ground should be flat. The field of application should be finely cultivated to ensure that the ground is flat, no large clods, no pits.
2, "two uniform": the drug should be evenly mixed on the carrier, spray or toxic soil should be even.
3, "San Zhun": the timing of application, the amount of application, the area of ​​the application of the plot. For example, 40% oatmeal is used to control wild oats, and 3 kg/ha is used before sowing.
4, "four look": look at the seedlings, grass, weather, soil quality. It is not easy to apply to unrooted or thin seedlings: according to the type and growth of weeds; when the temperature is low, the application rate is the upper limit; the weight of the soil is higher, the amount of sandy soil is less; the soil is dry. No medicine.
5, "five no": seedlings weak seedlings do not apply medicine; paddy field water is less than 3 cm or water depth flooded heart leaves do not apply; field soil is too dry to apply; when there is heavy rain or when there is dew on the leaves, do not apply; No rice is applied in the paddy field.
(5) Master the performance of the drug. Master whether the agent is volatile, photolyzed, and susceptible to physical or chemical reactions in the soil.
(6) Defining the “main attack locationâ€. In general, the herbicide "main attack site" of soil treatment is the part of weeds that has just sprouted, young stems and leaves, that is, before 3 leaves. Sulfosin is treated as stems and leaves at the weed stage, absorbed by stems and leaves and then transmitted to other tissues.
(7) The time of administration is reasonable. If the enemy is in the 2 leaf stage, the butachlor is 2-3 days before sowing, and the trace of glyphosate increases with the increase of the leaf area of ​​the weed.
(8) Play the role of water. Xicaojing, Guoer, Hedazhuang, Nongde, etc., keep the water layer 4-6 cm after application, can exert the effect of the drug, and no phytotoxicity; while the herbicide and herbicide ether are easy to accumulate in the field. Produce phytotoxicity.
(9) Prohibition of chaos and confusion. Mixture of herbicides can improve the efficacy and expand the spectrum of killing grass, but blindly mixed, easy to cause phytotoxicity. If the enemy can not be mixed with organophosphorus or carbamate; xyltetrachloride can not be mixed with acidic pesticides.
(10) Cleaning spray equipment. The sprayer that has used the herbicide should be cleaned first, then rinsed with water first, then repeatedly with soapy water or 2-3% alkaline water, and finally rinsed with water.
Third, the remedy of the drug. Once herbicides are used to cause phytotoxicity, effective measures should be taken to remedy and minimize possible losses.
(1) Detoxification: (1) When the drug is used the most, the field irrigation water should be drained immediately, washed with new water several times, and neutralized with acidic herbicides such as lime. (2) If there are many herbicides on the plant, it can be rinsed with sprinkler mechanical water to reduce the poison attached to the leaves. (3) When local phytotoxicity occurs in the field, first rinse the water, cultivate, and then replenish the seedlings, and then add quick-acting fertilizer. (4) If the field is poisoned seriously, the plot should be exposed to the sun, deep-washed after leaching, and then planted without affection, otherwise it will be re-irrigated. Or plant a small amount of sensitive crops and observe for 10-15 days.
(2) Strengthening field management. When the phytotoxicity is light, timely topping or removing the affected part, adding quick-acting fertilizer and rational irrigation; when severe, ploughing the land, replanting or replanting; when the cystic leaves are found in the grass, more fertilizer can be applied. Organic fertilizer can also be sprayed with dilute ammonia or 1% lime water and sprayed with hormone pesticides.
(3) Application of plant growth regulators. Spray 4% gibberellin EC to promote crop growth.
(4) Application of safety agents. Safeners, also known as antidotes, protect crops and detoxify a variety of herbicides. If the seeds are coated with activated carbon or roots, stalks, or evenly spread on the soil surface, simazine can be prevented from causing phytotoxicity to soybeans and wheat; guanidine phthalic anhydride can prevent sulfides such as acetaminophen against corn. The phytotoxicity.
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