How to judge and remedy crop phytotoxicity
2022-11-25 14:05:23
Phytotoxicity refers to improper use of pesticides and does not apply strictly according to requirements, causing various pathological reactions of protected crops, including plant damage caused by drugs, growth retardation, plant metamorphosis, production reduction, production, and even death. A series of abnormal physiological changes. Such as: defoliation, fruit drop, yellowing of leaves, leaf spots, wilting, burns, dwarfing, deformity, plant death, quality decline, etc., that is, crops have been tainted.
First, the symptoms of crop phytotoxicity:
According to the time when the symptoms of phytotoxicity occur, it can be divided into acute phytotoxicity, chronic phytotoxicity and residual phytotoxicity.
1. Acute phytotoxicity: The symptoms exhibited in a short period of time (usually within 10 days) after pesticide application are mostly spots, chlorosis, burns, wilting, defoliation, falling flowers, fruit drop, leaf curl deformity, young tissue scorching, Loss of green discoloration or yellowing.
2, chronic phytotoxicity: the phytotoxicity will not appear immediately after application, the symptoms are not obvious, it is not easy to judge in a short time, generally only 10 days after application. Mainly affecting the physiological activities of crops, mostly manifested by weak photosynthesis, slow growth, dysplasia, delayed results, fruit shape and small deformity, early fruit drop, grain imperfections, and decreased quality. Identification of chronic phytotoxicity should generally be compared to healthy crops.
3. Residual phytotoxicity: It is caused by pesticides or their decomposition products that remain in the soil. Since about half of the pesticides on the ground are sprayed on the ground, some of these pesticides decompose slowly, and they accumulate slowly after being adsorbed by the soil. Some residual periods are longer. When the pesticides are accumulated to a certain extent, the growth of the crops will be affected. Residual phytotoxicity is not caused by the application of pesticides in this sputum, but the result of the combination of pre- and pre-multi-crop crops. The symptoms are similar to those of chronic phytotoxics, and it is actually a kind of chronic toxicity.
Second, the cause of phytotoxicity: the cause of phytotoxicity is more complicated, mainly in the following aspects:
1. Pesticides: Pesticides are toxic substances used to control diseases, insects and grasses. Exceeding a certain amount, they often have certain toxic effects on plants, especially herbicides, and their control objects - comparison of physiological characteristics between weeds and crops Close, if the selectivity is poor, it is easy to cause phytotoxicity to crops. The main factors causing phytotoxicity include the physical and chemical properties of pesticides, the quality of pesticides, the use of mixed substances, the application amount and concentration, the unclean packaging containers, the frequency and time of application, the application methods, the cleaning of instruments, and the disappearance of labels.
2. Crops: (1) Crop types and strains: Different crops show different resistance and sensitivity to each pesticide. (2) Crop growth period: The sensitivity of crop growth period to pesticides is quite different. Generally, the drug resistance in seedling stage is poor, and it is easy to cause phytotoxicity. (3) Plant parts: The sensitivity of the plant parts to pesticides is large, the general stems are highly resistant, and the leaf resistance is poor, so the symptoms of phytotoxicity are first manifested on the leaves. (4) Crop growth: Crop malnutrition, weak growth is prone to phytotoxicity, and vice versa.
3. Environment: Crop phytotoxicity is closely related to natural environmental conditions such as temperature, humidity, rainfall, wind, wind direction and soil. (1) Temperature: The higher the general temperature, the higher the activity of pesticides and the metabolism of crops, and the more likely it is to cause phytotoxicity. (2) Humidity: If the humidity is too high, too much moisture may cause phytotoxicity. (3) Wind: spraying herbicides, causing damage to sensitive crops due to drift caused by wind. (4) Soil: The sandy soil has low organic matter content, weak adsorption to pesticides, easy leaching and diffusion, and is susceptible to phytotoxicity to some soil-treated crops. In addition, the pH value of the soil is also related to the production of phytotoxicity.
Third, ways to avoid the key:
1. Adhere to the application and application after the first test: First, it is necessary to clarify the application scope of the pesticide, the object of prevention and treatment, the appropriate period of treatment, the dosage or concentration of the pesticide, the application method and the precautions. In addition, different crops and different growth stages are not sensitive to pesticides. In order to expand the scope of use, it is necessary to expand the test crops.
2. Rational use of pesticides: The selection of pesticides should not only have good control effects on the control objects, but also require pesticides to be safe for the applied crops. Therefore, the sensitivity of crops should be considered when selecting pesticides, and pesticides that are sensitive to crops should not be used.
3. Strictly control the dosage of pesticides: strictly control the concentration and dosage, and do not increase the concentration and dosage.
4. Master the application period: select the appropriate stage for the control object during the period of crop resistance to avoid the occurrence of phytotoxicity.
5, the appropriate application method: according to pesticide performance and sensitivity to crops, pesticide formulations, weather conditions to determine the appropriate application method.
6. Pay attention to the quality of application: spray the pesticide evenly after spraying, and do not use it for pesticides that have been stratified or precipitated; at the same time, pay attention to uniform spraying and select the appropriate spray width to prevent re-spray.
7. Do not mix pesticides at random: When the pesticides are mixed, test them before use, and prove that they are effective and can be used in large areas without causing phytotoxicity.
Fourth, crop remedies:
When it is found that the pesticide field has caused phytotoxicity, corresponding remedial measures should be taken in time according to the cause of the phytotoxicity and the degree of crop damage, so as to minimize the phytotoxicity.
1. Flushing with water: If the pesticide is sprayed wrongly, the crop should be washed with a large amount of water immediately to reduce the absorption of pesticides by the plant; if the soil treatment agent is used incorrectly, the field irrigation should be repeated.
2. Neutralization of spraying: The phytotoxicity of acidic pesticides can be neutralized by spraying alkaline pesticides, and the alkaline pesticides are neutralized by acidic pesticides or other acidic substances. For example, the phytotoxicity caused by copper ions in Bordeaux mixture can be sprayed with 0.5%-1% lime water, the phytotoxicity caused by stone sulphur mixture, sprayed with 400-500 times rice vinegar, and the phytotoxicity of oxidized dimethoate. Spray 200 times of borax solution 1-2 times or decompose with a stone sulphur mixture.
3, fertilization remedy: after the occurrence of phytotoxicity in the crop, the growth is blocked, the growth is weak, and timely nitrogen, phosphorus, potassium or human excrement can promote the recovery of the injured plant. Especially for the phytotoxicity of the symptoms of the leaves, the application of fertilizer can reduce the degree of phytotoxicity.
4. Strengthen management: strengthen the cultivation and management of the affected crops. First, remove the dead leaves and leaves to prevent the spread or infection; secondly, cultivate the soil, improve the permeability of the soil, promote the development of roots, and enhance the absorption of water and fertilizer by the roots. Ability; third is to do a good job in pest control.
First, the symptoms of crop phytotoxicity:
According to the time when the symptoms of phytotoxicity occur, it can be divided into acute phytotoxicity, chronic phytotoxicity and residual phytotoxicity.
1. Acute phytotoxicity: The symptoms exhibited in a short period of time (usually within 10 days) after pesticide application are mostly spots, chlorosis, burns, wilting, defoliation, falling flowers, fruit drop, leaf curl deformity, young tissue scorching, Loss of green discoloration or yellowing.
2, chronic phytotoxicity: the phytotoxicity will not appear immediately after application, the symptoms are not obvious, it is not easy to judge in a short time, generally only 10 days after application. Mainly affecting the physiological activities of crops, mostly manifested by weak photosynthesis, slow growth, dysplasia, delayed results, fruit shape and small deformity, early fruit drop, grain imperfections, and decreased quality. Identification of chronic phytotoxicity should generally be compared to healthy crops.
3. Residual phytotoxicity: It is caused by pesticides or their decomposition products that remain in the soil. Since about half of the pesticides on the ground are sprayed on the ground, some of these pesticides decompose slowly, and they accumulate slowly after being adsorbed by the soil. Some residual periods are longer. When the pesticides are accumulated to a certain extent, the growth of the crops will be affected. Residual phytotoxicity is not caused by the application of pesticides in this sputum, but the result of the combination of pre- and pre-multi-crop crops. The symptoms are similar to those of chronic phytotoxics, and it is actually a kind of chronic toxicity.
Second, the cause of phytotoxicity: the cause of phytotoxicity is more complicated, mainly in the following aspects:
1. Pesticides: Pesticides are toxic substances used to control diseases, insects and grasses. Exceeding a certain amount, they often have certain toxic effects on plants, especially herbicides, and their control objects - comparison of physiological characteristics between weeds and crops Close, if the selectivity is poor, it is easy to cause phytotoxicity to crops. The main factors causing phytotoxicity include the physical and chemical properties of pesticides, the quality of pesticides, the use of mixed substances, the application amount and concentration, the unclean packaging containers, the frequency and time of application, the application methods, the cleaning of instruments, and the disappearance of labels.
2. Crops: (1) Crop types and strains: Different crops show different resistance and sensitivity to each pesticide. (2) Crop growth period: The sensitivity of crop growth period to pesticides is quite different. Generally, the drug resistance in seedling stage is poor, and it is easy to cause phytotoxicity. (3) Plant parts: The sensitivity of the plant parts to pesticides is large, the general stems are highly resistant, and the leaf resistance is poor, so the symptoms of phytotoxicity are first manifested on the leaves. (4) Crop growth: Crop malnutrition, weak growth is prone to phytotoxicity, and vice versa.
3. Environment: Crop phytotoxicity is closely related to natural environmental conditions such as temperature, humidity, rainfall, wind, wind direction and soil. (1) Temperature: The higher the general temperature, the higher the activity of pesticides and the metabolism of crops, and the more likely it is to cause phytotoxicity. (2) Humidity: If the humidity is too high, too much moisture may cause phytotoxicity. (3) Wind: spraying herbicides, causing damage to sensitive crops due to drift caused by wind. (4) Soil: The sandy soil has low organic matter content, weak adsorption to pesticides, easy leaching and diffusion, and is susceptible to phytotoxicity to some soil-treated crops. In addition, the pH value of the soil is also related to the production of phytotoxicity.
Third, ways to avoid the key:
1. Adhere to the application and application after the first test: First, it is necessary to clarify the application scope of the pesticide, the object of prevention and treatment, the appropriate period of treatment, the dosage or concentration of the pesticide, the application method and the precautions. In addition, different crops and different growth stages are not sensitive to pesticides. In order to expand the scope of use, it is necessary to expand the test crops.
2. Rational use of pesticides: The selection of pesticides should not only have good control effects on the control objects, but also require pesticides to be safe for the applied crops. Therefore, the sensitivity of crops should be considered when selecting pesticides, and pesticides that are sensitive to crops should not be used.
3. Strictly control the dosage of pesticides: strictly control the concentration and dosage, and do not increase the concentration and dosage.
4. Master the application period: select the appropriate stage for the control object during the period of crop resistance to avoid the occurrence of phytotoxicity.
5, the appropriate application method: according to pesticide performance and sensitivity to crops, pesticide formulations, weather conditions to determine the appropriate application method.
6. Pay attention to the quality of application: spray the pesticide evenly after spraying, and do not use it for pesticides that have been stratified or precipitated; at the same time, pay attention to uniform spraying and select the appropriate spray width to prevent re-spray.
7. Do not mix pesticides at random: When the pesticides are mixed, test them before use, and prove that they are effective and can be used in large areas without causing phytotoxicity.
Fourth, crop remedies:
When it is found that the pesticide field has caused phytotoxicity, corresponding remedial measures should be taken in time according to the cause of the phytotoxicity and the degree of crop damage, so as to minimize the phytotoxicity.
1. Flushing with water: If the pesticide is sprayed wrongly, the crop should be washed with a large amount of water immediately to reduce the absorption of pesticides by the plant; if the soil treatment agent is used incorrectly, the field irrigation should be repeated.
2. Neutralization of spraying: The phytotoxicity of acidic pesticides can be neutralized by spraying alkaline pesticides, and the alkaline pesticides are neutralized by acidic pesticides or other acidic substances. For example, the phytotoxicity caused by copper ions in Bordeaux mixture can be sprayed with 0.5%-1% lime water, the phytotoxicity caused by stone sulphur mixture, sprayed with 400-500 times rice vinegar, and the phytotoxicity of oxidized dimethoate. Spray 200 times of borax solution 1-2 times or decompose with a stone sulphur mixture.
3, fertilization remedy: after the occurrence of phytotoxicity in the crop, the growth is blocked, the growth is weak, and timely nitrogen, phosphorus, potassium or human excrement can promote the recovery of the injured plant. Especially for the phytotoxicity of the symptoms of the leaves, the application of fertilizer can reduce the degree of phytotoxicity.
4. Strengthen management: strengthen the cultivation and management of the affected crops. First, remove the dead leaves and leaves to prevent the spread or infection; secondly, cultivate the soil, improve the permeability of the soil, promote the development of roots, and enhance the absorption of water and fertilizer by the roots. Ability; third is to do a good job in pest control.
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