How to choose herbicides for peanut fields and mung bean fields? Application timing and precautions

Weeds have a great impact on crop growth. Chemical herbicides have the characteristics of fast effect and saving labor and time. So what herbicides should be used in peanut fields and mung bean fields? When is the best time to apply them? What are the precautions?

Herbicides for peanut fields

The common weeds currently found in peanut fields mainly include crabgrass, goosegrass, foxtail, barnyardgrass, Chinese sprangletop, lambsquarters, purslane, copperleaf, cocklebur, velvetleaf, Asiatic dayflower, small bindweed, thistle, and purple nutsedge, etc.

There are many types of herbicides for peanut fields currently sold on the market. Let us talk about the advantages and disadvantages of a few common formulations, and then choose specifically according to the weed situation.

1. Quizalofop-p-ethyl + fluoroglycofen-ethyl: The price is very cheap, but weeds tend to rebound, and it is also ineffective against purple nutsedge;

2. Quizalofop-p-ethyl + fomesafen: The price is a bit more expensive than the first one, but it is less prone to rebound. It is likewise ineffective against purple nutsedge. What needs attention here is that data reflect that using this formulation in the north is prone to cause phytotoxicity, while it is relatively stable in the south.

3. Quizalofop-p-ethyl + bentazone: The price is higher than the above two. It mainly targets purple nutsedge, but the amount should be appropriately increased. It will not leave residue, and its effect on other weeds is average.

4. Quizalofop-p-ethyl + bentazone + acifluorfen: A three-way compound. First, about the effect: it is certainly better than the above two-way compounds. It has good effects on common weeds in peanut fields as well as purple nutsedge, and it also leaves no residue. The only difficult thing to accept is the price, which can be 2-3 times more expensive than commonly used ones.

5. Quizalofop-p-ethyl + bentazone + fomesafen: It is also a three-way compound, and its weed control effect is also good, but compared with point 4, this formulation can also be used on soybean, that is, a herbicide suitable for both peanut and soybean. Likewise, the price is not low.

Now that the formulations and how to choose the herbicide have been explained, next let us talk about some precautions or methods during application:

1. The best application period for peanut herbicides is the 2-4 leaf stage of weeds. If the weeds are too small, some will still grow out later; if the weeds are too large, their resistance is greater and the weeds will not be killed thoroughly.

2. Do not apply the herbicide during the high-temperature period at noon. There are two reasons: first, evaporation is too fast and the effect is poor; second, to prevent heatstroke and ensure personal safety. Generally choose to apply before 10 a.m. or after 16 p.m.

3. When mixing the pesticide, remember to dilute it twice. The specific method: pour the pesticide into a bucket (or sprayer tank), first add part of the water to dilute it, and after it is diluted, add a large amount of water. The purpose of doing this is to make the pesticide solution more uniform, so that in the same field one patch will not suffer phytotoxicity due to a large amount of pesticide while another patch does not kill the weeds.

4. When there is standing water in the field and rainwater or dew on the peanut leaves, do not apply the herbicide. Why? For fear of phytotoxicity. When there is water on the peanut leaves, after the herbicide is sprayed, large water droplets form and then flow into the heart leaves. At this time, the concentration of the herbicide in the heart leaves is too high, which can very easily cause phytotoxicity.

5. Do not apply herbicides when the seedlings are weak. What is weak seedlings? Short plants, yellowing, and wilting, which may be caused by seeds, pests, diseases, and other reasons. No matter the cause, do not apply herbicides at this time, because the peanut seedlings themselves are already weak, and once the herbicide is not used well, phytotoxicity is unavoidable.

6. Pay attention to drift. For example, if corn, vegetables, sesame, and other crops are planted nearby, and the pesticide is applied on a windy day, the wind may blow the pesticide solution onto the neighboring crops, causing phytotoxicity to those neighboring crops.

Herbicides for mung bean fields

Barnyardgrass, crabgrass, foxtail, amaranth, lambsquarters, copperleaf, and others are the main weeds in mung bean fields. Their damage seriously affects the yield and quality of mung beans, and manual control is time-consuming and labor-intensive. Applying chemical herbicides has become the main measure for weed control in mung bean fields. According to different application periods, chemical weed control in mung bean fields can be divided into pre-sowing soil treatment, post-sowing pre-emergence soil treatment, and post-emergence stem and leaf treatment.

1. Pre-sowing soil treatment: Before sowing mung beans, use 70-100 ml of 48% trifluralin per mu, dilute with 30-45 kg of water, spray evenly and thoroughly on the soil surface, then form ridges, and wait 5-7 days until the chemical has fully diffused in the soil before sowing.

2. Post-sowing pre-emergence soil treatment: Use 200-300 ml of 48% alachlor (Lasso) emulsifiable concentrate per mu, dilute with 30-45 kg of water, and spray evenly on the soil surface after sowing and before emergence. Or use 60-80 ml of 96% metolachlor (Dual Gold) emulsifiable concentrate per mu, dilute with 30-45 kg of water, and spray evenly on the soil surface after sowing and before emergence. Under unfavorable conditions such as drought, after spraying it is best to shallowly incorporate it into the soil to preserve efficacy.

3. Post-emergence stem and leaf treatment: ① Imazethapyr (Pursuit, imazethapyr), which can be used in mung bean fields to control grass weeds and annual broadleaf weeds. Use 5% imazethapyr aqueous solution, 100-130 ml per mu, dilute with 30-35 kg of water, and spray evenly at the 2 compound leaf stage of mung bean and the 2-4 leaf stage of weeds. It should be noted that imazethapyr has a long residual effect period and may affect the following crop, so when using it, attention should be paid to considering the safety of the following crop. ② Bentazone (Basagran), which can be used in mung bean fields to control broadleaf weeds. The dosage of 48% bentazone aqueous solution is 100-120 ml per mu, dilute with 30 kg of water, and spray evenly at the 3 compound leaf stage of mung bean and the 3-5 leaf stage of broadleaf weeds. ③ Fomesafen (Flex), which can be used in mung bean fields to control broadleaf weeds. Use 60-70 ml of 25% fomesafen (Flex) aqueous solution per mu, dilute with 30 L of water, and spray evenly after mung bean emergence at the 1-2 compound leaf stage and the 2-4 leaf stage of broadleaf weeds. When using fomesafen (Flex), the dosage per mu should be less than 70 ml, otherwise phytotoxicity may occur.

There are relatively many agents for controlling grass weeds. Sethoxydim (Nabu), quizalofop-p-ethyl (Jinghecaoke), fluazifop-p-butyl (Jingwenshade), and clethodim (Select) can all be used after mung bean emergence to control grass weeds. Per mu, choose 60-80 ml of 12.5% sethoxydim (Nabu) emulsifiable concentrate, or 60-80 ml of 5% quizalofop-p-ethyl (Jinghecaoke), dilute with 30 kg of water, and spray evenly at the 2 compound leaf stage of mung bean and the 3-5 leaf stage of barnyardgrass. Per mu, you can also choose 30-45 ml of 15% fluazifop-p-butyl (Jingwenshade) or 50-60 ml of 12% clethodim (Select), dilute with 30 kg of water and spray, and spray evenly at the 3-5 leaf stage of grass weeds. It has a very good control effect on grass weeds.

For mixed use of agents, in order to effectively control grass weeds and broadleaf weeds, you can choose 25% fomesafen (Flex) aqueous solution + 15% fluazifop-p-butyl (Jingwenshade) emulsifiable concentrate, 21.4% acifluorfen (Blazer) aqueous solution + 15% fluazifop-p-butyl (Jingwenshade) emulsifiable concentrate, and 15% fluoroglycofen-ethyl (Kuochu) emulsifiable concentrate + 15% fluazifop-p-butyl (Jingwenshade) emulsifiable concentrate. All can achieve the purpose of effectively controlling grass weeds and broadleaf weeds, and are safe for the crop.

Stem and leaf treatment is the most commonly used method of chemical weed control in mung bean fields. In production practice, attention should be paid to the rotation and mixing of herbicides in order to delay the emergence and development of weed resistance and achieve the best control effect.

Using herbicides can effectively prevent weed damage. Therefore, when using herbicides, everyone must master the concentration and application period well, and use them strictly according to the dosage specified in the instructions.