At present, the resistant weeds in rice crop fields in China mainly include alfalfa, Qianjin, weedy rice, wild sage, ragwort, and hollow lotus seed (water peanut). The main varieties of herbicides used in paddy fields are quinclorac, cyhalofop-lam, penoxsulam, oxazolamide, butachlor, pretilachlor, bensulfuron-methyl, pyrazosulfuron-methyl and benzene. Dasong, 2 methyl 4-chloro and its compound preparation. The following 15 herbicides are specifically described below:
1, pyrazosulfuron
Pyrazosulfuron-methyl is a sulfonylurea herbicide, which is a selective systemic herbicide. It is mainly absorbed by roots, rapidly transfers in weed plants, inhibits growth, and weeds gradually die. Rice can decompose the agent and has little effect on rice growth.
The drug has stable efficacy and high safety, and the duration of action is 25 to 35 days. Applicable to rice fields, live fields, transplanted fields. It can control annual and perennial broadleaf weeds and sedge weeds, such as heterosex sedge, water sedge, sedge, ragweed, cress, squash, wild sage, sage, qingping, é³¢intestinal. It is not effective against valerian and thousand gold.
Generally used in the 1~3 leaf stage of rice, 15~30 grams of 10% wettable powder per acre is mixed with poisonous soil, and it can also be sprayed with water. Keep the water layer for 3 to 5 days after the medicine. Transfer the field, use the medicine 3 to 20 days after the insertion, and keep the water for 5 to 7 days after the medicine.
Precautions:
Pyrazosulfuron-methyl is safe for rice, but late rice varieties (ç²³, japonica) are relatively sensitive, and should be avoided in the late bud stage, otherwise it is easy to produce phytotoxicity.
2, bensulfuron-methyl
Bensulfuron is a selective systemic herbicide for rice field. It can effectively control 1-year-old and perennial broad-leaved weeds and sedges, which can be absorbed by weed roots and leaves and transmitted to other parts. For rice safety, the method of use is flexible. Suitable for rice fields to control 1 year old and perennial broadleaf weeds and sedges.
Rice paddy field and direct seeding field can be applied after sowing to weeds within 2 leaf stage. Control 1 year old broadleaf weeds and sand grass, use 20% wettable powder 20-30g per acre, spray 30kg of water or 20kg of mixed tidal soil. Keep the water layer 3-5cm for 3-4 days.
Rice transplanting fields can be used for 3 weeks before and after transplanting, but it is better to apply them 5-7 days after transplanting. Use 10-30 grams of 10% wettable powder per acre to prevent perennial weeds and remove valerian, and the dosage can be increased to 30-50 grams. The water-repellent layer is applied 5cm, which can be sprayed on water or mixed with fine soil. The water layer can be kept for 3-4 days and naturally dried. Bensulfuron-methyl has a good effect on weeds within the 2-leaf stage, and has a poor effect over 3 leaves.
Precautions:
It is not suitable for alfalfa, and it should not be used in the field of alfalfa. The spray equipment should be rinsed after use. At the time of application, there must be a water layer of 3-5 cm in the rice field to evenly distribute the agent. 7 days after application, it will not drain or string water, so as not to reduce the efficacy.
3. Butachlor
Butachlor, also known as Marsett, is a special herbicide for rice fields with high selectivity. Gramineous weeds, annual sedges and some annual broadleaf weeds, such as valerian, thousand gold, sedge, broken sedge, cattle felt, etc. It has a good preventive effect on the ragweed, knuckle, cusp flower and flamingo
The wet nursery in the south of Putian is completed 2-3 days before sowing. For each hectare, use 60% emulsifiable oil of 1125-1500 ml (75-100 ml per acre), add 450 kg of water (30 kg per acre), spray on the soil surface, keep water for 2-3 days after application, and sown after draining. When applying the medicine, the bed surface should be level without water, so as to avoid phytotoxicity.
The live field is 2-3 days before sowing or after the seedling. Use 1200-1500 ml of 60% emulsifiable concentrate per hectare (80-100 ml per acre), spray with water, keep the shallow layer of water, and then drain the seeds. After the seedling application, it must be carried out before the seedling 1 leaf 1 heart to 2 period, before the 2 leaf stage of valerian, use 60% emulsifiable milk 150-1875 ml per hectare (100-125 ml per acre), spray with water, spray When the field is wet, there is no water layer. In order to prevent rain and water in the field, the gap in the field can be opened.
3-7 days after transplanting the transplanted field, the weeds were in the germination to 1.5 leaf stage. In the southern region, 1500-1650 ml (60-110 ml per acre) of 60% emulsifiable concentrate per hectare, and 1650-2100 ml (110-140 ml per acre) per hectare in the northern region, mixed with fine soil. When applying the medicine, there should be 2-3 cm of water in the field, and keep water for 3-5 days after application.
5-7 days after throwing the hoe in the field, the seedlings have survived, and the weeds are in the germination to the l.5 leaf stage with 60% emulsifiable concentrate of 1500-1650 ml per hectare (100-110 ml per acre), and mixed with fine soil. When applying the medicine, there should be 2-3 cm of water in the field and keep water for 3-5 days.
Precautions:
In the transplanting of the field, the quality of the seedlings is not good, and it may cause phytotoxicity if it rains or is too deep after application.
The use of butachlor in water live field and open field wet field is less safe and prone to phytotoxicity. It should be tested in the community and gained experience before it can be applied.
The application period should be better before the weed seeds or psyllium germination, and the effect after the two-leaf stage of valerian decreased significantly.
If it is not possible to transplant in 3-4 days after land preparation, it is recommended to apply the medicine immediately after site preparation to effectively control weed sprouting and increase rice safety.
4, pretilachlor
Acetochlor, also known as Swift, is a herbicide for rice fields with high selectivity. It is safe for rice and has a wide spectrum of killing grass. Weed seeds absorb the medicinal agent during germination and the roots are poorly absorbed. It can only be used for pre-emergence soil treatment.
Rice germination is also sensitive to pretilachlor. To ensure early drug safety, pretilachlor is often added to the safener CGA123407. Applicable to rice control of alfalfa, bald oyster, thousand gold, goosegrass, cow felt, narrow leaf diarrhea, water leek, shaped sedge, broken sedge, clove scorpion, ragweed, etc. 1 year old grass undergraduate and broad Leaf weeds.
In the water live field and the use of the field, first well, and then germination sowing. 2-4 days after sowing, shallow shallow water layer, use 100-115 ml of 30% emulsifiable concentrate per acre, spray evenly 30 kg of water or 20 kg of mixed tidal soil or spread the whole field, keep it moist, and there is no water in the field. Mainly used to control grass weeds.
The product belongs to 2-acetyl acetanilide herbicide, which is a cell division inhibitor. It can be used for soil treatment to control rice field sedge, sedge, cow felt, ragweed, and narrow leaf diarrhea. Usually used 3 to 5 days before transplanting. This product has a poor selectivity for wet-growing rice when applied alone, and has excellent selectivity for in-line rice when used together with chlorpyrifos.
Precautions:
After the ground is well prepared, it is necessary to sow and use the medicine in time, otherwise the weeds will be unearthed and affect the efficacy. The sowing rice has root buds normal. Avoid buds without roots. In the northern rice area, the application period should be extended appropriately, first test, and then promoted in large areas to avoid phytotoxicity.
5, grass enemy
A herbicide with a systemic action of herbicides. Can be absorbed by the roots and buds of weeds. Particularly easy to be absorbed by the sheath. It has special effects on alfalfa. And the application period is wider. But the grass is narrow. Applicable to rice fields to control alfalfa, cattle grass, and sedge.
It can be applied before planting, first make a good field, make a seesaw, then use 100-150 ml of 96% emulsifiable oil per acre, 10 kg of fine moist soil, evenly spread the soil surface and immediately mix the soil. Keep the shallow water layer, and after 2-3 days, you can sow the rice seeds that have been germinated and exposed. Normal management will be carried out later.
It can also be used when the rice seedling grows to the 3rd leaf stage, and the psyllium is in the 2-3 leaf stage, with 96% emulsifiable concentrate of 100-150 ml per acre, and 10 kg of mixed tidal soil. Keep the water layer 4-5cm for 6-7 days. If the valerian is 4-5 leaf stage, the dosage should be increased to 150-200 ml.
Precautions:
1 The grass is highly volatile, and the water layer is kept for 7 days after application and after application, otherwise the efficacy cannot be guaranteed.
2 Indica rice is particularly sensitive to grasses, and the dosage is too high or the drug is not uniform, which is easy to cause phytotoxicity.
3 Grass has special effects on alfalfa, and it is not effective against other broad-leaved weeds and perennial weeds. If it is combined, it can be mixed with other herbicides.
6, Hecao Dan
Hecaodan is a systemic selective herbicide for internal absorption, mainly used for weed roots and shoots, and used as a soil treatment agent. It is safe for rice and has excellent control effect on alfalfa. Suitable for rice, wheat, soybeans, peanuts, corn, vegetable fields and orchards, such as valerian, cattle grass, sedge, thousand gold, crabgrass, valerian, foxtail, broken sedge, sage, see Mai Niang and so on.
The water live field can be applied before or after sowing. Use 50-300 ml of 50% emulsifiable concentrate per acre and spray 35 kg of water. Keep the water layer 3-5cm, 5-7 days when applying. Dry live broadcast can be evenly sprayed at 30-40 kg.
Precautions:
Mixing with enemy can get better results.
7. Oxazolamide
Oxazolamide is an aryloxyphenoxypropionate herbicide developed by the Korea Institute of Chemical Technology. It is excellent for controlling most annual grass weeds. Oxazolamide is safe for rice and can effectively prevent it. Main weeds in paddy fields, such as valerian, Qianjin, Matang and Goosegrass.
It is mainly used for transplanting and directing rice fields for weeding. Low toxicity, environmentally safe, widely miscible, and expected to be used for weeding other crops and lawns, is a promising herbicide.
It is mainly degraded in the soil by both chemical and microbial pathways. At 25 °C, the half-life in soil under normal conditions is 40-60 days. A single dose through the foliar spray, mainly to prevent transplanting and directing the annual grass weeds in the field. It is an ACC enzyme inhibitor that inhibits the synthesis of plant fatty acids.
Precautions:
Within a few days after administration, the sensitive varieties showed leafy greening and inhibited growth. Some varieties showed dryness and even died 2 weeks after application.
8. Quinclorac
Quinclorac is a selective herbicide for controlling rice sedge, and it is a hormone-type quinoline carboxylic acid herbicide. The symptoms of weed poisoning are similar to those of auxin. It is mainly used for controlling valerian and has a long pot life. Both 1-7 leaf stages are effective. Rice is safe. Residues in the soil are mainly through photolysis and degradation of microorganisms in the soil.
Mainly used in rice paddy sedge. It can also control rain long flowers, Tian Jing, cress, ragweed, and saponin. It can be applied in the 1-7 leaf stage of 秧田秧è‰, using 13.5-26 grams of active ingredient per mu, spraying, draining the water before the medicine, releasing the water back to the field after the medicine, and maintaining the 3-5 cm water layer. The live Tianji seedlings were applied after 2.5 leaf stage, and the dosage was the same as above.
Precautions:
1 The amount of residue in the soil is large, which is easy to cause phytotoxicity to the sputum, and the sorghum can be used to grow rice, corn, and sorghum. Solanaceae (tobacco, potato, pepper, etc.), Umbelliferae (carrot, celery), Polygonaceae (spinach, beet) Malvaceae, Cucurbitaceae (various melons), Leguminosae, Compositae, Convolvulaceae The crop is sensitive to the drug.
2 can be mixed with chlorpyrifos, bensulfuron-methyl, pyrazosulfuron, propanil, cyhalofop-butyl ester, etc. to expand the herbicidal spectrum.
In some parts of the region, chloroquine acid was used excessively throughout the year, resulting in cumulative phytotoxicity in the field. If used too early, excessive, or water retention over the heart leaf susceptible to phytotoxicity, the typical symptom of quinclorac on phytotoxicity in rice is the emergence of green onion seedlings (heart leaf vertical roll and heal into onion tube, more tips Can be unfolded), the leaf color is more normal; the new leaves cannot be extracted due to the healing of the upper tissue, and the stalk is peeled off, and the new leaf is seen. The heart of the seedlings with severe damage is curled into a tubular erect, and they are usually dead after transplanting to the field; if they can survive, the formed tillers are also deformed, and some even the whole cluster of rice plants die. The seedlings with light phytotoxicity, the base of the stem is swollen, hardened and brittle, the heart leaves are narrowed and twisted into deformities, but the tiller seedlings that grow after transplanting to the field still grow normally. Symptoms of phytotoxicity usually appear 10 to 15 days after application.
9, bis-oxalate
Bispyr is a pyrimidine salicylic acid herbicide and is a highly active acetolactate synthase (ALS) inhibitor. It can be quickly absorbed by the stems and leaves of weeds and transmitted to the whole plant to inhibit plants. The meristem grows to kill the weeds. Efficient, broad spectrum, and very low dosage.
It can effectively control weeds and other grass weeds in rice fields, and treat most broad-leaved weeds, some sedge weeds and valerian which are resistant to other herbicides. Such as: valerian, double-spotted gar, rice lychee, horse tang, stalk, stalk, stalk, maiden, northeast sweet grass, wolf grass, sedge, sunshine, sedge, broken sedge, Firefly, Japanese grass, stalk grass, ragweed, rain long flower, wild sage mushroom, Alisma, kohlrabi, cereal grass, cow felt, section vegetables, mozzarella, water bamboo leaves, hollow lotus seeds Most of the weeds commonly found in rice fields such as grass and flower buds. It has special effects on older sedge and double-spotted gar. It can kill valerian in the 1-7 leaf stage.
Direct seeding rice fields: can be used after the emergence of direct seeding rice and before heading, and the best effect is applied in the 3-5 leaf stage of Valerian. The direct seeding rice field uses 20% bispyribyl ether wettable powder per acre, 18-24 g, and water 25-30 kg, evenly spray the weed stems and leaves.
Transplanting fields or throwing fields: Rice transplanting fields or throwing fields should be applied after 15 days of transplanting or throwing, and then applied after the seedlings are returned to avoid premature use, and the resistance of the seedlings is poor, resulting in phytotoxicity. Use 20% bispyribyl ether wettable powder per acre 12-18 grams, water 25-30 kg, evenly spray weed stems and leaves.
Drain the field water before application, expose all the weeds, fill the water 1-2 days after application, and keep the 3-5 cm water layer for 4-5 days. Can only be used for weeding in paddy fields, do not use it for other crops.
Indica rice varieties have yellowing after spraying this product, which can be recovered in 4-5 days without affecting the yield. Valerian 1-7 leaf stage can be used, small sorghum, low dose, large valerian, high dose. Adding silicone additives during use can improve the efficacy.
Precautions:
After the application of cyhalofoprin and bispyribofin for two consecutive years, the chloroquine-resistant valerian also developed resistance to cyhalofop-butyl ester and bis-oxalyl, and the resistant valerian population had compound resistance. In some areas where bis-oxalate has been used, it is necessary to pay attention to this and be cautiously optimistic about field control to avoid poor control.
10. Pyrimidine
Pyrimidinyl ether is a novel oxime ester compound, a broad-spectrum selective post-emergence herbicide. The mechanism of action is similar to sulfonylureas and imidazolium herbicides, all of which are acetolactate synthase (ALS) inhibitors.
It has selective super-efficient post-emergence herbicidal activity against rice, common wheat and Zoysia, and has no pre-emergence herbicidal activity. It is used to control various grasses and broadleaf weeds such as valerian, big stalk, maiden and spicy sorghum. The effect of the plan is outstanding, and it is safe for rice and common wheat.
Precautions:
The herbicide weeding rate is slower and can inhibit weed growth after application, but it must die after 2 weeks. The drug is moderately broad and effective for the 1.5 to 6.5 leaf stage of valerian. In the 2.5-3.5 leaf stage, 100% control can be achieved at a dose of 10g/h; a dose of 20g/h can be achieved at a dose of 3.5% to 4.5%.
11, penoxsulam
Penoxsulam is a conductive herbicide with a wide spectrum of herbicides. It has good control effects on various weeds commonly found in paddy fields, including alfalfa, annual sedge and various broadleaf grasses, and has a long-lasting effect. Up to 30 to 60 days, a single medication can basically control the hazards of all seasons.
At present, the dosage form registered in China is 2.5% oil suspension agent (Taojie), and penoxsulam is safe for rice. It can be used from rice leaf stage to maturity stage, and it is safe for pupa. Some weeds that have developed resistance to sulfonylurea herbicides also have better control effects with this product.
It is absorbed by stems, leaves, shoots and roots, and is transmitted to the meristem through the xylem and phloem to inhibit plant growth and chlorotic growth. After 7~14 days, the buds turn red and necrotic, and the plants die in 2~4 weeks. The agent is a strong acetolactate synthase inhibitor, and the agent appears to be slow, and it takes a certain time for the weeds to gradually die.
It is suitable for dry land, rice, live fields, and throwing and transplanting fields of rice. The dosage is 15~30ga.i./hm2. The direct seeding field was applied to the seedlings in the early stage after the buds or after the irrigation. The transplanting cultivation was applied 5~7 days after the transplanting.
The application method can be sprayed or mixed with soil. The product is very safe for rice. When it is at a high dose, it has a certain inhibitory effect on the growth of rice roots in the early stage, but it recovers quickly and does not affect the yield. Penoxsulam can be quickly adsorbed by the soil.
It is weakly leached in the soil of most rice fields. Its adsorption capacity in clay soil and soil containing high organic matter is higher than that of light soil and low organic matter content. It has a risk of aggravating phytotoxicity in soils with a pH > 8.0.
The agent is easily migrated in the soil and is not retained for long periods of time. Because the saturated vapor pressure of the agent is low, it is not easy to evade from the water; in the paddy field, the half-life of the agent is 2~13d; photolysis and microbial degradation are the main disappearance pathways of penoxsulam.
It can resist hydrolysis in water, but it can disappear rapidly in the shallow water layer by photolysis. The photolysis of the aqueous solution is three ways: sulfonamide bridge cleavage, triazolyl and its substituents are gradually degraded, and sulfonyl photooxidation. This photolysis product can remain for a long time. In paddy soil, anaerobic microbial degradation is an important process for the disappearance of agents, and its disappearance rate is as fast as photolysis.
Precautions:
Penoxsulam has attracted attention due to its low toxicity, high efficiency and safety, and it will be further developed in rice application and become one of the important products.
12. Cyhalofoprin
Cyhalofop is a aryloxyphenoxypropionic acid herbicide. Selective herbicides in paddy fields can only be treated as stems and leaves, pre-emergence treatment is ineffective, and it has certain control effect on young sorghum, and can also control, crabgrass, double-spotted gar, foxtail, goosegrass, and maiden Wait.
Ineffective for sedge weeds and broadleaf weeds. It is efficient for thousands of gold. Cyhalofop is a uniquely safe variety of rice aryloxyphenoxypropionic acid herbicides, and like other varieties, it is also a systemic herbicide.
The absorption from cyhalofoprin to weeds is relatively slow and usually takes 1-3 weeks. The symptoms of weeds after application are as follows: the buds in the four-leaf stage shrink and cause death. The old leaves in the two-leaf stage are extremely small and remain green.
Rice (transplanted and broadcast) has excellent selectivity to rice, and selectivity is based on different metabolic velocities. In rice, cyhalofop-butyl ester can be rapidly degraded into diacids inactive to acetyl-CoA carboxylase. It is therefore highly safe for rice. Because of its rapid degradation in soil and typical paddy fields, it is safe for crops.
Precautions:
The drug is highly toxic to aquatic arthropods and avoids influx into aquaculture sites. It may exhibit antagonism when mixed with some broad-leaved herbicides such as pyrisulfuron, which shows a decrease in the efficacy of cyhalofop.
13, flupiroxyacetic acid
Chlorfluoxetine is a systemic post-emergence herbicide that is quickly absorbed by plants after the drug, causing the response of typical hormone herbicides to sensitive plants. The plants are deformed, distorted, and eventually die. Fluroxypyroxyacetic acid is a pyridinoxyacetic acid herbicide with systemic conduction and a typical hormonal herbicide reaction.
After seedling use, sensitive crops react with typical hormonal herbicides. Applicable to wheat, barley, corn, grapes, orchards, pastures, woodlands, lawns and other places to control broadleaf weeds; such as piglets, coiled stalks, purslane, nightshade, snails, scorpions, scorpions, etc. It is not effective for grass weeds.
The conversion of isooctyl clofibrate to flupiroxyacetic acid is herbicidal, and 288 g/l of isooctyl clofibrate corresponds to 200 g/l of flupiroxyacetic acid. As the area of ​​direct-seeded rice grows larger, flupiroxyacetic acid is slowly applied to direct seed rice to control some broad-leaved weeds, the most common being purslane, duck broad grass, alfalfa and water peanut.
Precautions:
Do not add silicone when clofibrate is weeded, and secondly, use it before the jointing stage of rice four-leaf stage.
14, dimethyl tetrachloride
Methyltetrachloride is harmful to the roots of rice. It used to be used in many places before plucking. It is thought that this will make the seedlings expand and become thicker or cracked. It is a selective hormonal herbicide.
Its mode of action is the same as that of 2, 4 drops. However, its volatility and speed of action are lower and slower than that of 2,4 drops of butyl acrylate, so it is safer to use in 2, 4 drops in cold regions. Gramineae plants are very sensitive at the seedling stage, and the resistance is gradually enhanced after the 3~4 leaf stage. The tillering stage is the strongest, and the sensitivity to the differentiation of the young ears is increased. Therefore, it is best to apply at the end of rice tillering.
Suitable for rice, wheat and other dryland crops to control Triloba, Agaricus, Alisma, Wild Citrus and other broadleaf weeds.
Precautions:
Methyltetrachloride is harmful to the roots of rice. It used to be used in many places before plucking. It is thought that this will make the seedlings better.
15, chlorpyrifos
Cedar pine, also known as bentazon, is a selective contact-type post-emergence herbicide used for weed seedling stem and leaf treatment. Mainly control water sedge, sedge, broken sedge, stalk sedge, squid, ox, grass, dwarf mushroom, wild sage, Alisma, sage, sage, squash, Vegetables, water leek, sausage, etc.
Putian and live field saplings 4-5 leaf stage, weed 3-5 leaf stage with 48% liquid 2250-3000 ml per hectare (150-200 ml per acre), add 450 kg (30 kg per acre) spray. Drain the field water in the evening before the application and moisten the spray. Inject 3-4 cm of water layer 1-2 days after the drug, and return to normal tube water after 3-5 days of water retention.
20-30 days after transplanting the transplanted field, weeds 3-5 leaf stage with 48% liquid 2250-3000 ml per hectare (150-200 ml per acre), spray with water. The day before the application of the drug, the field water was drained, the weed plants were all exposed, and all the plants were sprayed with the liquid medicine. The water was poured into the field 1-2 days after the application, and the normal water was restored.
Precautions:
It is not effective for grass weeds, and is generally mixed with other herbicides such as cockroach, but it cannot be mixed with enemy cockroaches, and it cannot be used in a short time.
Sprayed when the temperature is high and the sun is sufficient, the activity is strong, the weeding effect is good; when it is cloudy and the temperature is low, the spraying effect is poor. Therefore, it is better to apply the medicine on a sunny day.
(Article source: Zhuangjia Technology)
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