For the corn seedlings after the herbicide, corn growers around the country every year in use, but every year there will be corn drug damage, no effect after the beating and other issues, sometimes there will be herbicides after the corn seedlings, weeds are not dead, corn is dead, it is a headache for farmer users.
Today, I will talk in detail about when is the safest herbicide after corn seedlings, how to play the best effect, the best spraying time, spraying method, and what are the precautions for the use process? With a series of questions, let's take a look at it together:
The best time to spray the herbicide after corn seedlings
Since the absorption process of herbicide after the spray of maize seedlings takes 2-6 hours, in these 2-6 hours, whether the medicinal effect is good or not (that is, whether the weeding effect is ideal) is closely related to the temperature and air humidity.
In the high temperature, dry weather in the morning, noon or afternoon spraying, due to high temperature, strong light, liquid evaporation fast, spray after a while of liquid evaporation, so that the amount of herbicide into the body of the weed is limited, the amount of absorption is obviously insufficient, thus affecting the effect of weeding; at the same time, spraying at high temperature and drought, corn seedlings are also prone to drug damage.
The best spraying time is after 6 pm, because this time spraying, the temperature after application is low, the humidity is larger, the liquid stays on the weed leaf surface for a long time, the weed can fully absorb the herbicide ingredients, ensure the weed control effect, and the evening medication can also significantly improve the safety of corn seedlings, which is not prone to drug damage.
Several leaves of corn seedlings can be sprayed with herbicide after the corn seedlings
Maize 3-5 leaves, weed 2-4 leaf stage is the best, especially Yu Nongle mixed with 2,4-d butyl ester can not be applied after the 5-leaf stage of maize.
The weeds in the field are basically in place, and most of the weeds are sprayed at the 2 to 4 leaf stage. The application period is too late, the weed resistance is enhanced, and the weed control effect is affected. When spraying, the temperature is required to be 15 ~ 25 ° C, the relative humidity of the air is more than 65%, and the wind speed is less than 4 m / s. Select the spray equipment and nozzle according to the requirements and apply the drug according to the spray operation specifications.
How to play a good effect of herbicide after corn seedlings
To tell you a practical medicine process, summed up a method, under the premise of sufficient dosage, the more water the better (of course, not to say that there is no limit to adding water, relatively speaking), for example, the purchase of herbicides, it is recommended to buy a bottle of 1 bucket of water 1 acre of land, that is, about 15 kg of water, sprayed in an acre of land, but if you mix 20-25 kg of water, the same spray in an acre of land, the effect is better than 15 kg of water.
In the common point, 1 bottle of 1 bucket of water 1 acre of land into 1 bottle of 2 buckets of water 1 acre of land, interested friends can try, but pay attention, spray volume must be uniform, must not be more than a piece of less situation.
Look at the size of the grass
When spraying herbicides after spraying corn seedlings, many farmers have a misunderstanding that the smaller the weed, the smaller the resistance, the easier the grass is to kill. In fact, it is not, because the grass is too small to have a medicinal area, and the weeding effect is not ideal. The optimal grass age is 2 leaves, 1 heart to 4 leaves and 1 heart stage, when the weed has a certain medicinal area, the weed resistance is not large, and the weed control effect is remarkable.
Corn varieties
Because most of the herbicides after corn seedlings are now chimney sulfuron components, some corn varieties are sensitive to this ingredient and are prone to drug damage, so the corn fields that grow sweet corn, waxy corn, Denghai series and other varieties cannot be sprayed to prevent drug damage. For new corn varieties, try them before they can be promoted.
Pesticide mixing problems
For 7 days before and after the herbicide spraying, it is strictly forbidden to spray organophosphorus insecticides, otherwise it is easy to cause drug damage. However, it can be mixed with permethrin insecticides, and when spraying, it is necessary to pay attention to avoiding the heart lobe as much as possible and preventing the liquid from filling the heart.
This year, some cornfield Swedes and thrips have been severe, and imidacloprid or acetamidine can be used to control these two small pests, but do not mix with post-seedling herbicides when spraying, although imidacloprid or acetamiprid are not organophosphorus.
Because the control of two small pests requires the spray of heart leaves, if the spray heart leaf is mixed, it is easy to cause drug damage, and can be sprayed separately: the herbicide is sprayed after the seedling is sprayed in the front, followed by the heart leaf with imidacloprid or acetamidine.
The resistance of the weeds themselves
Since in recent years, the weeds themselves have been strengthened to resist stress, in order to prevent excessive evaporation of water in the body, weeds have not grown so watery and thick, but grow gray and short, and the actual grass age is not small (that is, the so-called "little old man"). Most of these weeds are covered with small white fuzzes to reduce the evaporation of water.
When spraying pesticides in this way, the liquid is topped by these small villi on the surface of the weed stems and leaves, the weeds themselves absorb very little, naturally affect the exertion of the medicinal effect, so no matter what medicine is applied in high temperature and drought, the amount of liquid sprayed should be increased to not affect the exertion of the medicinal effect, please do not spare the water when the farmer friend applies the medicine, do not spare the medicine.
Precautions for the use of herbicides after corn seedlings
1. Carry out regular spray according to the prescribed dose, and the dosage cannot be increased at will.
2, the use of "secondary dilution method", first mixed into the mother liquor, and then sprayed evenly on the water.
3. In general, the appropriate period for the use of herbicide after corn seedlings should be after 2 leaves of visible leaves of corn to 5 leaves of visible leaves. If the drug is used in the 5th to 7th leaf stage, it should be used between corn rows to avoid spraying the liquid into the heart leaf.
4. Some herbicides after corn seedlings are sensitive to sweet corn, farming, and inbred lines, and should not be used. Should be used in strict accordance with the herbicide label instructions.
5. Corn treated with organophosphorus agent is sensitive to post-seedling herbicides. The interval between the two doses is at least 7 days.
6. Use a motorized sprayer to apply the drug, do not increase the amount of medicine without authorization, and it is forbidden to repeat the spray.
7. Before the use of herbicides, pay attention to cleaning the sprayer that has sprayed organophosphorus pesticides.
8. The effect of medication is good after 4 pm, and the continuous high temperature weather (temperature exceeds 35 ° C) should be avoided.
It rains after the corn has been herbicide, and the next day is it still heavy sprayed?
First of all, we do not recommend hitting the herbicide after the second pass of seedlings.
So some farmer users are afraid that the grass will not die, and want to play a second time, what to do?
1. It rains immediately after the medicine.
2, heavy rain or heavy rain, a long time.
3, broad-leaved grass 3-5 days, sharp-leaved grass after 5-7 days, there is no poisoning phenomenon, corn also grows normally.
Meet the above 3 points can be resprayed once.
opposite:
1, the rain is not large, and the time is short.
2. After 6 hours of herbicide after spraying corn seedlings, it rains.
3. Weeds have been poisoned.
If the above 3 points are met, it is not recommended to respray to avoid drug damage.
Some friends will say, I do not meet the above conditions, but when playing the second time, do not hit the corn, only hit the weeds, directional spray, can you.
A: That's certainly possible!!
The mixing of pharmacies is to pay attention to scientificity, before the mixing of pharmacies, we must first understand the physicochemical properties of the pharmacy, the characteristics of action and biological activity, etc., and then through the field application test, and finally can be used in a large area, to not stop mixing abuse, the consequences are unimaginable.
So can corn herbicides be mixed with insecticides, what kind of insecticides can be mixed with them, and what is the effect after mixing? With a series of questions, let's take a look at the following:
Why do so many people wonder about this question? It's nothing more than wanting to be lazy and lazy! Whether it is possible or not, let's first study the following:
The principle of mixed use of pesticides
1. There is no adverse chemical reaction (such as hydrolysis, alkalil solution, acidolysis or redox reaction, etc.) between the mixed varieties, which ensures normal efficacy or efficiency, and does not affect the physical properties of the agent (such as emulsification, suspension rate reduction, etc.).
For example, most organophosphorus insecticides cannot be mixed with Bordeaux liquid, stone sulfur compounds, etc.; powders cannot be mixed with wettable powders and soluble powders.
2. After the mixing of different varieties, the crop cannot be harmed. For example, after the combination of organophosphorus insecticides and barnyards, rice will produce medicinal harm, and Bordeaux liquid is mixed with stone sulfur compound, which is easy to cause chemical harm to crops.
3. After the pesticide is mixed, it does not increase the toxicity and ensures the safety of people and animals.
4. Mixed use should be reasonable. Including the reasonable combination between this species, such as the prevention of soybean field grass weeds, only with the capture of net, cover grass can be prevented, and then use the two mixing, although from the stability of the drug is feasible, but it is unreasonable to mix, neither increase efficiency, nor expand the scope of prevention and control, stick use is not necessary.
The purpose of mixing pesticides is to save labor and time, improve economic benefits, such as after making a mixture, the additional cost is very large, which is not allowed.
5. Pay attention to the antagonism between pesticide varieties to ensure the effect of mixing, such as the mixing of bendarone and nayu net due to antagonism and reduce the control effect of grass weeds.
Can corn herbicides be mixed with insecticides
For crops, there is pre-seedling (or pre-bud) treatment, which mainly refers to the pre-sowing (or pre-transplanting) of crops, or before the emergence of seedlings after crop sowing, and the soil spray treatment is closed to kill unborn weeds.
Such herbicides in maize fields include amide acetochlor, fine isopropylmethylamide, triazenzothene thymudine, etc., which can prevent a variety of annual grasses and some small seed broad-leaved weeds in the field, if it is in the three northeastern provinces, it will also use mixture varieties of herbicides such as 2,4-d butyl ester to expand the herbicide spectrum or increase the efficacy.
If there is no application during this period or the soil sealing effect is not good, you can choose to use a post-seedling herbicide to spray the stem and leaf of the weeds that have emerged from the seedlings, including sulfonylurea-type nicosulfuron (Japan Ishihara Corporation), etc., the control effect is OK.
remind:
We must pay attention to strict use of the technical points and precautions of the label and instructions of the herbicide pesticide to avoid causing drug accidents.
suggestion:
It is best not to mix, the two drugs have different emphases, one hit grass, one hit corn. In addition, insecticides may contain organophosphorus components, which are easy to mix with corn seedling products and cause drug damage, so it is not recommended to mix.
Analysis of the reasons why corn herbicides and insecticides are not mixed:
1, do not know what the herbicide and insecticide are what ingredients, in terms of corn herbicides, herbicides containing chimney sulfuron and insecticides containing organophosphorus mixed, there will be drug damage, that is, within 7 days after the corn herbicide, organophosphorus insecticides can not be used.
2, put aside the medicinal harm, corn herbicide is mainly sprayed on the grass, so that the grass to absorb the medicinal solution, and then kill the weeds, and the insecticide is hit on the corn leaf, so that the corn leaf absorbs the medicinal solution, to achieve the purpose of insect prevention and insect control. If you mix it up, do you say it's mainly on corn or on weeds?
Source: New Sannong