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Introduction of commonly used herbicides for weed species

1. Butachlor: Herbaceous weeds, annual sedges, such as valerian, thousand gold, sedge, broken sedge, cattle felt, ragweed, squash, cuspidate and squid , annual broadleaf weeds, have a good control effect.

2, acetochlor: alfalfa, ragweed, sedge grass and other annual grasses, some broad-leaved weeds, have a good control effect. Such as.

3. Acetochlor: It has good control effect on alfalfa, water leek, calf, ragweed, oxweed, thousand gold, squash, sedge, and sorghum.

4, bentazon: on water sedge, shaped sedge, broken sedge, squid, ox, grass, dwarf mushroom, wild sage, Alisma, sylvestris, ragweed, section vegetables, Mo Shang Weeds such as vegetables, water leek, and sausages have good control effects.

5, 2, 4-butyl butyl ester: for the control of broadleaf weeds such as ragwort, wild sage, and weeds such as striated grass, oxweed, etc., have better control effect.

6, 2 methyl 4-chlorosodium: mainly control amaranth, sedge, Jing Sanling, stalk sedge, ragweed, oxweed, wild sage, dwarf mushroom, wild scorpion, four leaf ping, eye dish, water leek , section dishes, etc.

7. Pyrazosulfuron-methyl: mainly for controlling ragweed, cultivar, kohlrabi, dwarf mushroom, cress, diarrhea, water dragon, green ping, sedge, water sedge, cattle grass, firefly, Broad-leaved weeds and sedge weeds such as calves, alfalfa and broccoli.

8, cyclamate: the main control rain long flower, eye dish, ragweed, section vegetables, valerian, Alisma, sage, Mo Shang, cuspid flower, wild sage, wolf grass, shaped sand Weeds such as grass, sedge, cow felt, broken sedge, firefly, water cotton, and small algae.

9, rushing grass net: mainly control eye vegetables, ragwort, oxweed, section vegetables, valerian, four leaves Ping, wild sage, shaped sedge, algae and so on.

10, enemy cockroaches: the main control of valerian, at the same time for the prevention and control of water purslane, ragwort and dry field crabgrass, foxtail, wild carp and other seedlings also have a good effect.

The above are some commonly used herbicide types, which basically cover the common weed types in the field. You can use them according to the types of weeds in your field.

Factors affecting the efficacy of herbicides

Herbicides are biologically active compounds whose efficacy depends on both the weed itself and the environmental conditions and methods of use. Take a look at the following factors to see if you have noticed during the herbicide application.

temperature

The high temperature is conducive to the herbicide being absorbed by the weeds, and the effect is good. (but not the higher the temperature, the better) The temperature is too high, and the sprayed mist is quickly evaporated. Especially for some volatile herbicides and photolysis-decomposing herbicides, the herbicidal effect will be reduced, such as 2.4-D. Fluorin, Heda Zhuang, Methoc tetrachloride, etc., will also cause phytotoxicity due to volatilization and drift to sensitive crops around. When the temperature is too low, the grass is used, and the plant can not be degraded in time, which is prone to phytotoxicity.

The correct application should be: high temperature season, sunny and windless before 11 am and after 4 pm; low temperature season should be between 10 am and 3 pm.

Air humidity

In general, the high humidity of the air is beneficial to the herbicide being absorbed by the weeds, and the effect is good. The best time is that there is no dew on the leaves, no rain, and the air humidity is above 60%. Do not apply if the dry heat season is too dry.

Soil Moisture

Adequate soil moisture, strong growth of crops and weeds, is conducive to the decomposition of pesticides and the absorption of pesticides by the crops and transported in the body, so as to achieve the best herbicidal effect, especially the soil treatment agent must have soil moist conditions to play. Good efficacy. If the soil is dry, the crops and weeds grow slowly, the crop tolerance is poor, and the weed stems and leaves form a thicker stratum corneum, which affects the absorption and conduction of the herbicide, thereby reducing the efficacy of the herbicide. At the same time, in order to adapt to the arid environment, most of the pores are closed, which affects the absorption of the medicament, and the root system is more developed, which increases the difficulty of prevention. Therefore, in the dry weather, high limit is recommended, and the amount of water spray should be increased at the same time.

precipitation

Rain soon after application, the liquid is easily washed away, affecting the efficacy.

illumination

Paraquat, herbicide ether, and accompanying farmer are all photoactivated herbicides, which only kill grass under the action of light. Photosynthetic inhibitors such as simazine, diuron, and chlorpyrifos also need to inhibit the photosynthesis of weeds in the presence of light and exert herbicidal effects. Fluorin and other applied to the soil surface is volatile, easy to decompose when light is used, and it should be mixed with the topsoil in time.

Soil pH

When the pH is between 5.5 and 7.5, most of the herbicides can work well. The soil with acid and alkali can decompose some herbicides, thus affecting the efficacy. If the soil-blocking herbicide is acidic, the herbicidal effect in the saline-alkali soil is poor or even ineffective. For example, the bio-sulfuron degradation rate in acid soil is fast, affecting the drug effect, and the degradation rate is slow in alkaline soil, which is easy to cause phytotoxicity to the susceptible crop.

Soil texture and organic matter content

Soils with loose texture and low organic matter have low adsorption capacity, and excessive amounts are easily leached to cause damage to crop roots. The soil with high content of cohesive soil and organic matter has strong adsorption capacity, so that the liquid can not move in the soil solution to form a uniform soil layer, which may cause the phenomenon of “unable to seal” and affect the effect. Therefore, the dosage should be appropriately increased, or Recommended usage limit. Herbicides are generally not used in soils with high organic matter and high water fertility.

Water quality

Refers to the hardness and pH of the water that is applied during the application. Hardness refers to the amount of Ca2+ and Mg2+ ions contained in 100 ml of water. Since the active ingredients of some herbicides are easily fixed by complexing with these two ions to form a salt, the hardness of the water may reduce the efficacy of the herbicide. Pesticides with acid-base are mixed with water with higher basicity or higher acidity, which will affect the stability of the agent and thus reduce the herbicidal effect.

Wind speed

Herbicides should be applied in the absence of wind or breeze. Wind-dried herbicides are prone to mist drift and harm sensitive surrounding crops. Especially volatile herbicides should be used with special care.

Grass age

Weeds are the best control period in the 2~3 leaf stage. The weeds are too old and the resistance is increased, and the dosage must be increased.

What are the technical requirements for the use of herbicides?

First, the use of herbicides: There are two ways to use herbicides, namely stem and leaf treatment and soil treatment. The soil treatment can be divided into pre-treatment and post-sowing soil treatment.

1. Stem and leaf treatment: The method of spraying herbicide directly on the stems and leaves of weeds is called stem and leaf treatment. This method is generally carried out after weed emergence. The herbicide is used as the stem and leaf treatment, and the liquid is sprayed on the stems and leaves of the weeds to ensure the safety of the crop.

2, soil treatment: soil treatment, is to spray the herbicide, spray, pouring, watering, dusting or poisonous soil, etc., applied to the soil surface or soil to form a certain thickness of the soil layer, contact weeds Seeds, shoots, seedlings and other parts are absorbed to kill weeds.

3. Time of use: The use time of herbicides is divided into three periods: one is that there is no crop growth before sowing, and the weeds are treated with stems and leaves or soil treatment with weeds to eliminate weeds, which is called soil treatment before sowing. Second, after the crops are planted, the soil is blocked with a herbicide, and the soil is treated before seeding. The third is in the growing season of crops, generally using selective herbicides to spray the stems and leaves, killing weeds, called stem and leaf treatment. Pre-emergence treatment after sowing, also known as pre-emergence treatment, is the use of herbicides before emergence of crop seeds after seeding. This period is relatively short, only a few days, to be strictly controlled, according to the situation, use herbicides before the seedlings. Soil treatment before sowing, the effect of controlling weeds is better, but the application is not timely, it will affect the emergence of seedlings and phytotoxicity.

Two: technical requirements for the application of herbicides:

1, one level: the ground should be flat. The field to be applied should be finely cultivated to ensure that the ground is flat, no large clods, no pits.

2, two uniform: the drug should be mixed evenly on the carrier (medicine, medicine, fertilizer), spray or toxic soil should be even.

3, Sanzhun: the application time should be accurate, the application amount should be accurate, and the area of ​​the application site should be accurate.

4, four look: look at the seedlings, see the grass, look at the weather, look at the soil, flexible control of the application period, the amount of application and application methods.

5, five no: seedlings weak seedlings do not apply medicine, paddy field water is less than 3 cm deep or water depth flooding heart leaves do not apply medicine, poisonous soil is too dry or the soil is too dry to apply, there is dew on the leaves, rain does not apply a certain Some herbicides, no leakage of water. If the drug is applied in the above five cases, it is prone to phytotoxicity and the drug efficacy is not good.

What are the measures to improve the effectiveness of herbicides?

First, the accurate choice of herbicide: accurate choice of herbicides, weeding effect is good. Each herbicide has a certain herbicidal spectrum, which is destructive and selective. Killer herbicides have a wide spectrum of herbicides, some herbicides can kill monocotyledonous weeds, some can kill broadleaf weeds, others kill only a few or one weed, and some have one In addition to the safety of crops, it is not safe for other crops.

Second, strict control of the amount of herbicide: strict control of the amount of herbicides, is one of the measures to improve drug efficacy and prevent phytotoxicity. The recommended dosage of each herbicide is the result of many years of practice and various tests. The dosage should not be increased or decreased arbitrarily, so as to ensure the herbicide effect and no phytotoxicity. Otherwise, safe herbicides can also cause phytotoxicity.

Third, adhere to the best time to apply the drug: the best time to apply the drug, is the technical requirements to improve the herbicidal effect. The best time to apply the drug will be inaccurate, which will reduce the efficacy of the drug and even cause phytotoxicity.

Fourth, pay attention to the temperature of the application: temperature is an important factor affecting the growth of weeds and the efficacy of herbicides. Generally, when the temperature is high, it is beneficial to the herbicide effect and the herbicide effect is good.

5. Ensure proper temperature: Whether it is soil treatment or stem and leaf treatment, soil moisture is an important factor affecting the efficacy of herbicides.

6. Pay attention to soil properties: soil properties have a great influence on the efficacy of herbicides. Soils with high organic matter content have good agglomerate structure, large amount of herbicide adsorption, large amount of soil microbes, strong activity, and herbicides are easily degraded. The dosage is safe for crops, but the herbicidal effect is poor, so it is necessary to increase the dosage appropriately.

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(Source: Good Agricultural Resources Network)