How to use corn post-emergence herbicide?

1. How to choose corn post-emergence herbicide

At present, the main problem of jade chemical weeding is that the user did not undergo training before the herbicide, and carefully studied the basic knowledge, use method and safety evaluation standard of the herbicide. The only criterion for choosing a herbicide is that it is cheap.

A variety of herbicides can be divided into recommended varieties, high prices, good safety, and large profits; limited use of varieties, less safety, or residual phytotoxicity problems, reduced use of drugs, improved application Technology, get better security, make small money; eliminate varieties, also called non-use varieties, safe travel, or long residual herbicides, there are already alternative varieties, lose money varieties.

1.1 Choose a safe variety

1.1.1 Recommended varieties

Sulfosone, mesotrione, bentazone, clopyralid, broadleaf, rimsulfuron, and oxafluridone.

1.1.2 Restricted use of varieties

Nicosulfuron, oxazinone, cyanazine, atrazine, dicamba, bromoxynil, glyphosate, etc. and mixtures thereof.

1.1.3 Elimination (not recommended) varieties

After corn seedlings, 2,4-D (butyl ester, dimethylamine, isooctyl ester), 2 methyl 4 -chloro, paraquat and the like were eliminated .

1.2. Analysis of common safety problems after corn seedlings

(1) Analysis of nicosulfuron

1 The sensitivity difference between the nicosulfuron-methyl varieties is very significant. Most sweet corn varieties are sensitive to nicosulfuron, while a few corn hybrids are also sensitive. This sensitivity is controlled by single dominant genes. In breeding, application 1 A patient with tolerance can overcome this sensitivity. Only a very small number (> 5% ) of the dent corn hybrids are sensitive to nicosulfuron, a sensitivity that is a simple inheritance of nuclear genes. Nicosulfuron is suitable for dentate, semi-dental and durum corn, and its safety order is dentate > hard grain corn > popcorn > sweet corn.

It is safer for nicosulfuron. The corn varieties that are relatively safe when used are Laiyu No. 2 , Laiyu No. 9 , Gaonong No. 1 , Gaonong 9 01 , Xing Kang No. 2 , Yuyu No. 9 and Xiyu 3. No., Taiyu No. 2 , Nongda 108 , Dongdan No. 8 , Dongdan No. 16 , Liao 31 , Liao 120 , Liaodan No. 37 , Tidan 12 , Tidandan 17 , Tidandan 19 , Zhengdan 14 , Zhengdan 18 , Zhengdan 518, 90 blessed, Chuandan 21, single 984 Lu, Lu 8009 single, single economic No. 7, No. 5 Gimhae, Gimhae 26, Xiyu 3, Danyu 39, Jiyu No. 9, No. 1 Yong Yu, 306 single, planted Yu 1, Liaoning original No. 1, 215 Dan Shen agriculture 87, 50 Lu Shan Lu Shan 98, Yedan 4, Yedan 20, No. 7 Ji single, Lian 15, high aGRICULTURAL No. 1 , No. 18 , Liao 526 , Yuyu No. 25 , Ludan No. 284 , etc.

Under adverse conditions, there may be phytotoxicity (moderately sensitive) to nicosulfuron. In the case of high temperature, low temperature, drought, corn growth retardation and other adverse conditions, the use of nicosulfuron or excessive use may cause symptoms of phytotoxicity. varieties are Yong Yu No. 1, No. 9 Yu Ji, 958 Cheng, Zhengdan No. 14, No. 17 Shenyu, single 981 Lu, 19 into a single, Yuyu 22, CP 12, No. 5 single agricultural, Den No. 11 ( 9313 ), Shendan No. 16 , Danyu 413-2 , Lianyu 19 , Danyu 35 , Hudan 2000 , Qiangsheng 31 , Shendan No. 10 , Taiyu No. 2 , Wuyue 206, etc.

Smoke sensitive ethyl, not recommended Zhang maize varieties No. 9, No. 3 Den, Den No. 6, 9, etc. No. Den. There single 306, No. 26, 2 Yuyu Yuyu --25, 211 Yu, Lu Shan No. 50, No. 3 fresh sticky, waxy into 1, North, three (three North 2132) 2, high-priority 8, 22 new single, white corn stick, Dongdan 13, Beifeng 58, No. 1 Jingdan, Suyu (waxy) 19, Den No. 11 (3119), Liaodan 36, 19 into a single, high-priority 8 No., Shenyu No. 17 , Chengyu No. 1 , Eyu 10 , Shengshi 2000 , a certain variety of the Pioneer series. The new corn variety was introduced after the safety identification was carried out and nicosulfuron was used.

Corn 3-5 leaf stage â‘¡ application date of smoke ability to metabolize ethyl strongest, gradually reduce after 6 leaves, the use of corn after the 6-leaf stage, there may cause injury. Due to drought and low temperature in the northern spring corn field, the growth of corn is slow and the weeds are not tidy. When the weeds are out of the seedlings, the corn has exceeded the leaf stage; some of the first application is not effective, and the use of nicotin Long; summer corn field is mostly wheat interplanting corn, wheat is harvested after the third leaf stage of the corn, the weeds are not emergence, when the weeds are out of the seedlings, the corn has a leaf stage, and the application is too early or too late to cause phytotoxicity.

3 Temperature influence After the application in the north, the temperature is lower than 10 °C for 2 days, and the metabolism of nicosulfuron in the corn is slow, that is, phytotoxicity occurs.

4 The dosage is too large or repeated application. Excessive use of nicosulfuron is more common, and the dosage is as high as 200-240 g.ai/hm2.

5 mixed with other herbicides caused by phytotoxicity of corn seedlings, nicosulfuron and 2, 4 drops, 2 methyl 4 chlorine mixed, often occur 2 , 4 drops, 2 methyl 4 chlorine hormone herbicides, often put this type The phytotoxicity is treated as a nicosulfuron. Symptoms of phytotoxicity: the leaves are thick green, twisted, onion-like leaves, plant deformed short, tassels are difficult to extract, and heavy tassels.

6 use of additives improperly aggravated phytotoxicity using synthetic non-ionic surfactants, mineral oil-type additives will increase the harm.

⑦ mixed with the organic phosphorus pesticide or organophosphorus pesticides before and after administration within 7 days.

8 non-mixable varieties: chlorpyrifos, 2, 4- drip, bentazone + atrazine mixture.

9 Residues and rotations are long-lasting herbicides of Nicosulfuron. The dosage of nicosulfuron is more than 60 g (active ingredient) / hectare, wheat and barley should be separated by 8 months; soybeans, peas and cotton should be separated by 12 months. • Beet, flax, rapeseed, sorghum, millet, potato, kidney bean, tobacco, sweet potato, onion, pumpkin, watermelon, cucumber, sage, pepper, eggplant, cabbage, radish, cabbage, spinach, carrot, etc. month. In order to solve the problem of residual phytotoxicity of the crops after the crop, it is recommended to reduce the dosage of nicosulfuron and the combination of atrazine, and the dosage of nicosulfuron is 30-40 g (active ingredient)/ha.

( 2) Why is cornfield restricted to use oxazinone? Azinone can only be used in soil organic matter before corn seedlings

Above 2% of the soil, the soil with less than 2% organic matter in the corn field was exposed to heavy rain after application in the pre-emergence seedlings. After the corn seedlings began to turn yellow from the lower first leaf, the serious whole plant died. In the single-crossing of corn, the father's phytotoxicity in the inbred lines is heavier than that of the female parent, often resulting in the death of the father.

( 3) Why is corn field restricted to use cyanazine?

Cyanazine is not recommended for use after corn seedlings. Cyanazine is applied after corn seedlings, under low temperature and rainy conditions, or too late, and more than 5 leaves after corn seedlings, which may cause phytotoxicity. Symptoms of phytotoxicity are inhibition of growth, leaves chlorotic and yellow, and severe leaves die.

( 4) Why is cornfield restricted to use dicamba?

The dicamba is a hormonal herbicide. It is used at low temperature before seedlings, and the metabolism is slow. The dicamba can accumulate in the germinated seeds, so that the primary roots increase, the growth is inhibited, the upward growth is weakened, and the leaf shape is narrowed. In the early stage of supporting the root growth of corn seedlings, the use of excessive dicamba can make the supporting roots flatten, and the onion-like leaves appear, and the stems are fragile and easy to fold. It is not recommended for use in the alpine region before seedlings. After the seedlings, the dosage should be strictly controlled, and it must be sprayed evenly.

( 5) Why does the corn field limit the use of bromoxynil?

Bromobenzonitrile is highly effective in the corn field or is applied under high temperature conditions. The symptoms are that the leaves have burning spots and the disease is aggravated. After the corn seedlings, the water consumption is too large, and the spraying mist is large. The liquid medicine is concentrated in the bell mouth of the corn seedlings, causing contact poisoning, and the heart leaves are dry and dry, and the leaves do not spread after tight packaging. It is necessary to apply at a suitable temperature. The TeeJet80015110015 fan-shaped nozzle is equipped with a 100-mesh column filter to reduce the spray volume to 100-150 liters/ha of artificial spray; the sprayer sprayer is below 100 liters/ha. .

( 6) Why not recommend 2, 4- drops after corn seedlings ?

2, 4- Dose is the oldest and most widely used herbicide. The processing dosage forms are esters and salts. Commonly used 2 , 4- butyl butyl ester, 2 , 4- diisooctyl ester, 2 , 4- D dimethylamine and other dosage forms. Hormone herbicides belonging, when trace amounts (less than 0.001%) of inhibition of plant growth when the plants growth stimulating effect, a high concentration (greater than 0.01%). The old book introduces the use of 2 , 4- drip weeding in the 4-6 leaf stage of corn seedlings. It refers to the corn farmer variety. With the development of science, the corn hybrids are promoted, and the phytotoxicity often occurs. The symptoms of the corn are damaged by the leaves. Forming a cylindrical leaf, commonly known as a cow tail seedling, does not open for a long time, the stem is brittle and easy to fold, the leaves are dark green, and when it is severe, the leaves turn yellow, dry and no ears; severely inhibit root growth, root enlargement, fibrous roots Less or no roots; the disease is aggravated; the tassel is difficult to extract, does not stick, or has a stick that is not agglomerated by powder, causing severe reduction in production.

After research, it was found that maize inbred lines were sensitive to 2, 4- tact, some single crosses were sensitive, double crosses were more resistant, and farmer varieties were resistant. Later, experts suggested that after the sensitivity identification, confirm that the corn varieties you planted are resistant and reused. The corn varieties in production are frequently replaced, and no one is sensitive to the identification of corn varieties. For the sake of production safety, it is no longer recommended to use 2 , 4- dose after corn seedlings , but also 2 to 4 chlorine is not recommended for corn seedlings.

2, mixed use can reduce phytotoxicity and residual phytotoxicity ‍‍

2.1 mixed good formula

3.36% suspending topramezone of 75 to 90 ml / ha atrazine + 38% + liquid discharge +2500 ml 1% vegetable oil type spray adjuvant.

10% mesotrione 1500 ~ 2000 ml / ha + 38% atrazine 2000 ~ 3000 ml; or 10% mesotrione 1500 ml / ha + 38% atrazine 2000 ml + spray volume 1% vegetable oil type Spray auxiliaries.

4% nicosulfuron 1000 ml / ha + 38% atrazine 3000 ml; or 4% nicosulfuron 750 ml / ha + 38% atrazine 2000 ml + spray amount 1% vegetable oil type spray auxiliaries.

15% sulcotrione 3000 ~ 4000 ml / ha + 38% atrazine 2000 ml + spray volume 1% vegetable oil type spray auxiliaries.

4% nicosulfuron 1000 ml / ha + 38% atrazine 2000 ml + 75% clopyralid 75 ~ 100 g.

4% nicosulfuron 750 ml / ha + 38% atrazine 2000 ml + 22.5% bromoxynil 750 ~ 900 ml.

4% nicosulfuron 750 ml / ha + 25% sulfimsulfuron 40 ~ 50 g / ha (spring corn).

4% nicosulfuron 350 ml / ha 25% + rimsulfuron + 50 g of 38% atrazine 2,200 milliliters.

48 % bentazone 1 5 00 ml / ha + 4% nicosulfuron 1000 ml + 38% atrazine 2000 ml.

48 % bentazone 1 200 ml / ha + 4% nicosulfuron 750 ml + 38% atrazine 2000 ml + spray amount 1% vegetable oil type spray aid.

3.36% oxazolone 75~105 ml +90% atrazine 1050 g, or 38% atrazine 2 500 ml + spray amount 1% vegetable oil type spray aid.

3.36% oxazolone 75~105 ml + 4% nicosulfuron 750 ml spray volume 1% vegetable oil type spray aid.

4% nicosulfuron 1000 ml / ha + 70% oxazinone 100 g, or 4% nicosulfuron 750 ml / ha + 70% oxalofen 80 + spray amount 1% vegetable oil type spray aid.

Special Recommendations: functional plant nutrients added in corn fields with herbicide - 50 ml per acre prime graminicola care benefits + 50 ml herbicide effective to prevent injury, or injury to rescue, prevention of late maize large, Small spot disease, stem-based rot, ear rot and other diseases occur.

2.2 Maize seedlings herbicide compounding technology evaluation data

Numbering

Pharmacy

Dosage gram (ml) / hectare

usage time

Control object

safety

1

Carfentrazone-one 3.36% benzene + 38% SC atrazine

75-90 ejection amount +2500 + 1% vegetable oil type spray adjuvant.

After the corn seedlings are 2 to 4 leaf stage , the weeds are applied at the 2 to 5 leaf stage .

Annual grass weeds and broadleaf weeds (

Safe for corn, safe for later

2

10% mesotrione suspension + 38% atrazine

1500~2000+2000~3000 or 1500+2000+ spray amount 1% vegetable oil spray additive

After the corn seedlings are 3 to 5 leaf stage , the weeds are applied at the 2 to 5 leaf stage .

Annual grass weeds and broadleaf weeds

Under low temperature conditions, mesotrione has slight phytotoxicity to corn, does not affect yield, and is safe for later.

3

4% nicosulfuron +38% atrazine

1000+3000; or 750+2000 spray volume 1% vegetable oil spray aid.

The application was carried out before the corn seedlings 3 to 5, the weeds 2 to 4 leaf stage, and the perennial weeds 6 leaves.

Annual grass weeds and broadleaf weeds

Some varieties are sensitive to nicosulfuron-methyl, which is harmful to the crops.

4

15% sulcotrione + 38% atrazine

3000~4000+ 2000+ spray amount 1% vegetable oil type spray auxiliaries.

After the corn seedlings are 3 to 5 leaf stage , the weeds are applied at the 2 to 5 leaf stage .

Annual grass weeds and broadleaf weeds

Sulfolone has slight phytotoxicity to corn under low temperature conditions, does not affect yield, and is safe for later use.

5

Nicosulfuron 4% 38% + 75% + atrazine clopyralid

750+2000+75+ spray volume 1% vegetable oil spray additive

After the corn seedlings are 3 to 5 leaf stage , the weeds are applied at the 2 to 5 leaf stage .

Annual grass weeds and broadleaf weeds increase the control effect of perennial expanded leaf weeds

Some varieties are sensitive to nicosulfuron-methyl, which is harmful to the crops.

6

4% nicosulfuron + atrazine% +38 22.5% bromoxynil

1000+2500+750~ 900 or 750+2000+750+ spray amount 1% vegetable oil type spray auxiliaries.

Early corn seedling

Gramineae and broadleaf weeds

Some varieties are sensitive to nicosulfuron, which is harmful to high temperature or high water consumption. Bromobenzil has contact toxicity to corn, and then it is safe.

7

4% nicosulfuron + 70% oxazinone

1000+100 or 750+80

+ Spray amount 1% vegetable oil type spray aid.

3 to 5 leaf stage after corn seedling, 2 to 4 leaf stage of weed, and 6 years before perennial weed

Gramineae and

Broadleaf weed

Some varieties are sensitive to nicosulfuron, serious phytotoxicity, and safe for later crops

8

4% nicosulfuron + 25% sulfonamide + 38% atrazine.

500+40+2000

3 to 4 leaf stage after corn seedling, 2 to 4 leaf stage of weed, and 6 years before perennial weed

Gramineae and

Broadleaf weed

Some varieties are sensitive to nicosulfuron, serious phytotoxicity, and safe for later crops

9

9% nicosulfuron + 25% sulfonamide

750+40~50

3 to 4 leaf stage after corn seedling, 2 to 4 leaf stage of weed

Gramineae and

Broadleaf weed

Some varieties are sensitive to nicosulfuron, serious phytotoxicity, and safe for later crops

10

48 % bentazone + 4% nicosulfuron + 38% atrazine

1 500+1000+2000 or

1 200+750+2000+ spray volume 1% vegetable oil spray aid.

3 to 4 leaf stage after corn seedling, 2 to 4 leaf stage of weed

Gramineae and

Broadleaf weed

Some varieties are sensitive to nicosulfuron, serious phytotoxicity, and safe for later crops

2.3 corn cultivars refractory weed mixed formula

2.3.1 Chicory, thorns, comfrey

48% bentazone 2000 ml / ha + 5% nicosulfuron 1000 ml.

48% bentazone 3000 ml / ha + 38% atrazine 3000 ml.

25% sulfimsulfuron 75 g / ha + 75% thifensulfuron 15 g (restricted to use in the Northeast).

25% sulfimsulfuron 75 g / ha + 38% atrazine 2250 ml.

5% nicosulfuron 1000 ml / ha + 25% sulfimsulfuron 75 ~ 90 g.

2.3.2 Xiang Fuzi

25% sulfimsulfuron 75 g / ha + 38% atrazine 2000 ml.

48% bentazone 1500 ml / ha + 5% nicosulfuron 1000 ml.

48% bentazone 2000 ml / ha + 5% nicosulfuron 1000 ml.

48% bentazone 3000 ml / ha + 38% atrazine 3000 ml.

45% valerian 2000 ∼ 3000 g / ha + 38% atrazine 3000 ml

70.5% 2-methyl isothiazolone 700-900 / ha.

2.3.3. Tianxuanhua, bowling flowers, morning glory

20% fluoxetine 750 ∼ 1000 ml / ha + 5% nicosulfuron 1000 ml.

48% bentazone 2250 ml / ha + 5% nicosulfuron 1000 ml.

2.3.4 question Jing

70% oxaconazole 300 g / ha + 48% dicamba 300 ml.

2.3.5 small root garlic (è–¤ (xie ) white)

5% fluorosulfuron-methyl 540 g / acre + 38% atrazine 150 ∼ 200 ml / mu mixed. .

2.3.6 Xanthium

4% nicosulfuron 1000 ml / ha,

10% mesotrione 1500 ∼ 1950 ml / ha + 38% atrazine 2250 ∼ 3000 ml.

33.6% oxazolone 90 ∼ 112 ml / ha + 90% atrazine 1050 g (or 38% atrazine 2500 ml).

20% fluoxetine 750 ∼ 1000 ml / ha + 5% nicosulfuron 1000 ml.

48% bentazone 1000 ml / ha + 5% nicosulfuron 1000 ml.

70% oxazolone 300 g / ha + 38% atrazine 3000 ml.

45% valerian 2000 ∼ 30200 g / ha + 38% atrazine 3000 ml.

3, post-emergence herbicide use technology‍‍‍

3.1 Promote the "two downs and one plus" spraying new technology

In order to solve the problem of poor efficacy of spraying herbicides under high temperature and drought conditions, the plant protection station of Heilongjiang Provincial Land Reclamation Bureau has proposed a new technology of “two drops and one plus” spraying after many years of research . "Two drops and one plus" spray new technology to reduce the amount of liquid spray, reduce the amount of medication, add vegetable oil spray additives.

3.1.1 Reduce the amount of liquid spray

( 1) Select the outer water nozzle body

It is recommended to use the fast-assembled ARAG external water jet nozzle body, which has its own anti-drip valve. It has the same function as the anti-drip filter. The liquid does not take the pipeline and does not corrode the spray bar. It is not recommended to install the nozzle body quickly in the water. Because the liquid passes through the nozzle, it is easy to corrode the spray bar.

( 2) Select nozzles, filters

The artificial spray selects the SF80015 fan nozzle with a 100 mesh column anti-drip filter. The general sprayer sprayer selects the SF80015 fan nozzle with a 100 mesh column type anti-drip filter. The self-propelled sprayer chooses the SF8002 fan nozzle with a 50 mesh column anti-drip filter. It is not recommended to use a cone nozzle for a boom sprayer.

( 3) Spray droplet size and density requirements

Suitable sprayed postemergence herbicide spray droplet diameter field requires 250 to 400 microns, systemic herbicide spray droplet density of 30 to 40 / cm 2, spraying pesticides tag droplet density of 50 to 70 / cm 2 .

( 4) Design the spray root according to the spray droplet diameter and the droplet density

The manual knapsack sprayer sprays 100-150 liters/ha, and the sprayer sprayer sprays 75-100 liters/ha.

( 5) Spray pressure selection

The manual knapsack sprayer has 2 atmospheres, and the spray bar sprayer sprays the spray to 3 to 5 atmospheres.

( 6) Walking speed selection

Manual knapsack sprayer spray speed of 3 ~ 4k km / h, the general boom sprayer speed of 6 ~ 8 km / h. The high-powered self-propelled sprayer has a speed of 10 to 12 km/h.

3.1.2 Add vegetable oil spray aid

( 1) Suitable weather conditions

Spraying post-emergence herbicides is suitable for meteorological conditions (temperature 13 ~ 27 °C, gas relative humidity greater than 65% , wind speed less than 4 m / s; generally sunny before 8 am, after 6 pm, it is best to spray at night without dew The effect is best.), add 0.5% vegetable oil spray aid strip to the medicine box when spraying .

( 2) Unsuitable for meteorological conditions (temperature greater than 27 °C, air relative humidity less than 65% , wind less than 4 m / s) is generally not recommended. If you add 1% of vegetable oil spray aid in the medicine (or prevent refractory weed) box, you can work

3.1.3 reduce the amount of medication

(1) Determination of the amount of herbicide used

The recommended principle of post-herbicide is the test results under suitable meteorological conditions; the test results under unsuitable meteorological conditions are not used as the basis for the recommended dosage. The amount of herbicide used is based on the registered amount, and the addition of the vegetable oil type spray auxiliaries reduces the amount of the drug.

(2) Reduce the amount of medication

The use of vegetable oil spray aid can reduce the amount of herbicide by 30% to 50 % under suitable meteorological conditions. Under the meteorological conditions of high temperature and drought, the herbicide dosage can be reduced by 20% to 30 %.

( 3) Interval requirements for rainfall after application of post-emergence herbicides

Rainfall will cause the herbicide to be washed away from the weed leaves, causing significant losses. Generally rainfall of 1 to 2 mm, water soluble

The herbicide is washed away from the weed leaves; the rain is 5 to 10 mm, and the oil-soluble herbicide can be washed away from the weed leaves.

Different herbicides have different requirements on the interval between rainfalls. Pay attention to the weather forecast before application, and avoid the application of drugs and the interval between rainfalls is too short to affect the efficacy. For the herbicides to be used, please refer to Wang Xianfeng Xin Mingyuan, editor-in-chief of the "Herbalide Safety Application Manual", 2013 China Agricultural Press.

3.2. Plant protection machinery should be standard, and the use of technology should be standardized.

The use of standard plant protection machinery is the basic requirement for spraying herbicides. The non-standard performance is poor in the preparation of key components, the spray is not standard, the pressure is insufficient or too large, the leakage is dripping, the speed is too fast, and the final spraying is uneven, heavy spray or leakage. Severe spray, causing grass shortage or phytotoxicity.

Vigorously popularize the technical specifications for the use of plant protection machinery. The use of plant protection machinery is an agronomic measure. Every agricultural technician and boom sprayer operator should master the agricultural machinery and operators for plant protection machinery standards and technical specifications.

The use of plant protection machinery is not adjusted and operated according to the specifications, resulting in heavy drug damage and poor efficacy. The evaluation criteria are as follows:

Before the operation, it should be carefully adjusted according to the practical techniques of plant protection machinery, and the spray operation should be carried out after the standard is reached. The field work must be carried out in accordance with the technical specifications.

(Source: Pesticide Market Information )

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