Distribution and best control methods of weeds in corn fields in China! (comparative table of weed control effects of all kinds of herbicides)

According to the results of the national weed survey, there are 22 families, 38 genera and 43 species in corn field. The main harmful weeds in corn field are: Magnolia mandshurica, barnyard grass, dogtail grass, sagittaria, amaranth, purslane, iron amaranth. Li (fennel), thistle (large thistle and small thistle), field twisty flower, duck metatarsus, etc., and the seedling stage is the most harmful, which can cause maize plant dwarf, thin leaves and yellow stalks to seriously affect corn yield, and the yield can be reduced by about 35%.

1. Distribution areas and characteristics of weeds in corn fields in China.

Corn planting in China is divided into six regions: northern spring sowing corn area, Huang-Huai-Hai summer sowing corn area, northwest irrigated corn area, southern hilly corn area, southwest mountain corn area and Qinghai-Tibet Plateau corn area.

The grass damage in corn field is also divided into six regions: northern corn field grass damage area, Huang-Huai-Hai corn field grass damage area, northwest corn field grass damage area, Yangtze River valley corn field grass damage area, South China corn field grass damage area, Yunnan-Guichuan corn field grass damage area.

2. Carding of herbicides in corn field

Using herbicides to control weeds, on the one hand, we must kill weeds, on the other hand, we must avoid causing damage to crops in the same field or even subsequent crops, which puts forward high requirements for the scientific use of herbicides!

1. Main classification of herbicides in corn field.

(1) according to the time of use, corn herbicides can be divided into three categories:

The first category is post-sowing pre-bud herbicides, commonly known as closed herbicides, such as Acetochlor, atrazine, Metolachlor and so on.

The second type is the early post-seedling herbicide, that is, the small grass herbicide mentioned by farmers, (usually treated in the stems and leaves of corn with 3-5 leaves, it is often an internal selective herbicide), such as nicosulfuron, atrazine, nitrosulfonone (3-8 leaf stage of corn), 2min 4-drop, etc.

The third category is post-seedling herbicides, that is, what farmers call large herbicides (inactive herbicides) such as paraquat, glyphosate, etc.

(2) the herbicides in corn field can be divided into three types according to the treatment method.

1. Closed herbicide-pre-seedling soil treatment

2. stem and leaf treatment agent-post-seedling stem and leaf treatment

3. Universal type before and after seedling-with soil closure and stem and leaf treatment.

Scientific weeding of corn

2. Universal type before and after seedling-with soil closure and stem and leaf treatment.

3. The table of chemical weeding in corn field is clear.

4. Introduction of main herbicides in corn field.

5. Comparison of weeding spectrum and weeding effect of common herbicides in corn.

3. Control strategies of malignant weeds in corn field.

1. Duck metatarsus

(1), fenvalerate: 48% AS100-200ml/ mu of fenvalerate pine was used in 4-6 leaf stage of corn, stem and leaf treatment.

(2) chlorofluoropyloxyacetic acid + prednisone.

(3) chlorofluoropyloxyacetic acid + oxazolidone.

(4), Harry (70.5% 2A? Zolone WDG): 60 grams per mu after 5-leaf stage in corn field.

2. Abutilon:

The optional agents are: azosulfonamide, sulfenesulfuron, thiophenesulfuron, azazinone, propargyl fluoxetamine, promethazone, trimethopyr, nitrazenone, chloropyrone, formamidosulfuron, fluorosulfuron, chlorofluoropyloxyacetic acid.

3. Tian Xuan Hua

The optional agents are: prednisone, chlorofluoropyloxyacetic acid, 2-methyl-4-dioctyl ester, 2-methyl-4-chlorine, glyphosate, oxamidophos.

4. Ask Jing:

The optional medicaments are: 2pyrrine 4-diisooctyl ester, trimethoprim, trimethoprim, glyphosate, fluorosulfuron, azosulfonamide.

5. Borage, thorn, thorn (thistle):

Optional medicaments are: prednisone, 2meme 4-isooctyl ester, fluorosulfuron-methyl.

6. Rhizoma aconite:

(1) Dimethyl tetrachloride: 56% SP75-100g/ mu of dimethyl tetrachloride sodium salt can be sprayed on the stems and leaves of Rhizoma Cyperi by spraying water 30kg/ mu.

When spraying, it should be mainly sprayed on the stems and leaves of Rhizoma Cyperi, and sprayed on corn as little as possible. The suitable period of pesticide application should be strict, and it should be in 5-7 leaf stage and 5-6 leaf stage, not too early and too late, otherwise it is easy to cause drug damage, and if the application temperature is too high (above 32 ℃), it is also easy to cause drug damage to corn.

(2), 24-butyl ester: 3-5 days after corn sowing, 72% 2 4-butyl ester EC50-100ml per mu was used before emergence, and about 35 kg of water was evenly sprayed with soil surface and unearthed weeds. It can also be sprayed on weed stems and leaves with 72% 2 min 4-butyl EC40-65 ml per mu and about 35 kg of water at the 4-5 leaf stage after maize emergence.

(3), fenvalerate: 48% AS100-200ml/ mu of herbicide pine was used in 4-6 leaf stage of corn, and the stems and leaves were treated.

(4), azolidone: in the 3-5 leaf stage of corn, 50% oxazolidone DF5.3-8g/ mu and 30 kg of water can be used to control broad-leaf weeds such as Abutilon, Abutilon, amaranth, Chenopodium, Pig calamus, Solanum nigrum, White Mustard, Wild Sesame, Red Heart Chenopodium and other broad-leaf weeds and Cyperus.

Different from hormone herbicides such as dimethyltetrachloride and chlorofluoropyloxyacetic acid, azolidone has little effect on aerial rooting of corn. However, the use of high temperature on corn is easy to cause drug damage, which has a certain impact on the growth of corn. The pesticide must be applied before 8 o'clock in the morning and after 4 o'clock in the afternoon on a clear day, and the temperature should not exceed 30 ℃.

(5), Harry (70.5% 2A? Zolone WDG (60 grams per mu after 5-leaf stage in corn field) has a good control effect on stubborn weeds such as nicosulfuron and nitrosulfonone, which can not be solved by nicosulfuron and nitrosulfonone, such as Cypermus roxburghii, Rhizoma przewalskii, Portulaca oleracea, borage and other refractory weeds.

(6), 75% chlorosulfuron WDG: in the 3-5 leaf stage after maize seedling, 3-5 leaf stage of weeds, the best period is 4-5 leaf stage. The dosage of the preparation is 75%WDG45-60 g / ha and 15-30 liters of water.

It has high herbicidal activity for some common broad-leaved weeds in corn field and Cyperaceae weeds such as Cyperaceae, and is safe for most maize varieties. As a herbicide in corn field, it should be used with antidote MON13900.