When is the best time to hit the herbicide after corn seedlings? How to play? What should be paid attention to?

For corn post-seedling herbicides, corn growers use them every year, but every year there will be problems such as corn drug damage and no effect after beating, and sometimes there will be herbicides after beating corn seedlings. The weeds have not died, but the corn has died, which is a headache for farmers. When is the best time to hit the herbicide after the corn seedlings? How to play? What should be paid attention to?

The best spraying time of herbicide after maize seedling

As it takes 2-6 hours to absorb the herbicide after spraying corn seedlings, whether the efficacy is good (that is, whether the weeding effect is ideal) is closely related to air temperature and air humidity in these 2-6 hours.

Spraying in the morning, noon or afternoon when the temperature is high and the weather is dry, because the temperature is high, the light is strong, and the liquid volatilizes quickly, the liquid will evaporate soon after spraying, so that the amount of herbicide entering the weed body is limited and the absorption is obviously inadequate. thus affecting the weeding effect; at the same time, spraying in high temperature and drought, corn seedlings are also prone to drug damage.

The best spraying time is after 6 o'clock in the evening, because at this time, the temperature is lower, the humidity is higher, the liquid stays on the weed leaf for a long time, and the weeds can fully absorb the herbicide components to ensure the weed control effect. the use of medicine in the evening can also significantly improve the safety of corn seedlings and is not easy to cause drug damage.

Several leaves of corn seedlings can be sprayed with herbicides after corn seedlings.

3-5 leaves of maize and 2-4 leaf stage of weeds were the best, especially the mixture of Yunongle and 2mem4murD butyl could not be applied after the 5-leaf stage of corn.

The weeds were almost all in the field, and most of the weeds were sprayed at the stage of 2 to 4 leaves. When the application period was too late, the weed resistance was enhanced and the weeding effect was affected. Spraying should be carried out when the temperature is 15: 25 ℃, the air relative humidity is more than 65%, and the wind speed is less than 4 m / s. Select spray equipment and nozzles as required and apply according to the operation code of spraying operation.

How to get a good effect of herbicide after corn seedling

To tell you a method summed up in the actual drug administration process, under the premise of sufficient dosage, the more water the better (of course, it does not mean unlimited addition of water, relatively speaking). For example, if you buy a herbicide, it is recommended that one bottle of water per mu of land, that is, about 15 kilograms of water, is sprayed in an acre of land, but if you mix 20-25 kilograms of water, it is also sprayed on one mu of land. The effect is better than 15 kilograms of water.

In the vulgar point, a bottle of 1 bucket of water 1 mu of land into a bottle of 2 buckets of water 1 mu of land, interested friends can try, but note that the amount of spray must be uniform, must not be more than one piece of less.

Look at the size of the grass

When spraying herbicides after corn seedlings, many farmers have a misunderstanding that the smaller the weed, the less resistant the grass is, the easier it is to kill the grass. In fact, it is not, because the grass is too small to apply medicine area, the weeding effect is not ideal. The best grass age is from 2 leaves and 1 heart to 4 leaves and 1 heart, when the weeds have a certain drug area, the weed resistance is not big, and the weeding effect is significant.

Maize varieties

At present, most of the post-seedling herbicides of corn are nicosulfuron, and some corn varieties are sensitive to this composition and are prone to drug damage, so the corn fields planting sweet corn, waxy corn and Denghai series can not be sprayed to prevent drug damage. For new corn varieties, please try them first and then popularize them.

Mixed use of pesticides

It is forbidden to spray organophosphorus insecticides 7 days before and after spraying herbicides, otherwise it is easy to cause drug damage. But can be mixed with pyrethroids and carbamate insecticides, spray should pay attention to avoid heart leaves as far as possible, anti-drug liquid perfusion.

Swedish flies and thrips have occurred seriously in some corn fields this year. Imidacloprid or acetamiprid can be used to control these two small pests, but they should not be mixed with post-seedling herbicides, although imidacloprid or acetamiprid are not organophosphorus.

Because spray heart leaves are needed to control two kinds of small pests, if mixed with spray heart leaves, it is easy to cause drug damage, which can be sprayed separately: spray seedlings and herbicides in front, followed by imidacloprid or acetamiprid spray heart leaves.

The resistance of weeds themselves

In recent years, the resistance of weeds has been strengthened, in order to prevent excessive evaporation of water in the body, weeds do not grow so stout, but grow gray and short, and the actual age of the grass is not small (that is, the so-called "little old man"). Most of these weeds are covered with small white hairs 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 stems and leaves of the weeds, and the weeds themselves absorb very little, which naturally affects the exertion of the efficacy, so no matter what medicine is applied in high temperature and drought, the amount of liquid sprayed should be increased so as not to affect the exertion of the efficacy. Please do not cherish the water or medicine when applying the medicine.

Matters needing attention in the use of herbicides after Maize seedlings

1. Spray in accordance with the prescribed dose, and do not increase the dosage at will.

2. Using the "secondary dilution method", the mother liquor was prepared first, and then the water was uniformly sprayed.

3. Generally, the suitable period for the use of herbicides after maize seedlings should be after 2 leaves of visible leaves to before 5 leaves of visible leaves. If the medicine is used in the 5-7 leaf stage, it should be used between corn rows to avoid spraying the liquid into the heart leaves.

4. Some post-seedling herbicides are sensitive to sweet corn, seed production and inbred lines, and should not be used. It should be used in strict accordance with the instructions on the herbicide label.

5. The corn treated with organophosphorus agents was sensitive to post-seedling herbicides. The interval between the two drugs was at least 7 days.

6. when using a motorized sprayer, the dosage shall not be increased without authorization, and repeated spraying is prohibited.

7. Attention should be paid to cleaning sprayers that have been sprayed with organophosphorus pesticides before using herbicides.

8. The effect of medication is good after 4 o'clock in the afternoon, and avoid medication in continuous high temperature weather (the temperature is more than 35 ℃).

It rained after the corn was shot with herbicide. Will it be re-sprayed the next day?

First of all, we do not recommend a second post-seedling herbicide.

So some peasant users are afraid that the grass will not die and want to fight a second time, what should they do?

1. It rained immediately after the medication.

2. Heavy rain or torrential rain for a long time.

3. After 3-5 days of broad-leaved grass and 5-7 days of sharp-leaf grass, there was no poisoning, and corn grew normally.

To meet the above three points, you can spray again.

On the contrary:

1. It doesn't rain hard, and the time is short.

2. It was raining 6 hours after spraying corn seedlings with herbicides.

3. Weeds have been poisoned.

To meet the above three points, re-spraying is not recommended to avoid drug damage.

Some friends will say, I do not meet the above conditions, but the second time, do not hit the corn, only hit the weeds, directional spray, okay?

A: that must be possible!

The above article introduces in detail when to hit the herbicide after corn seedlings, how to hit it, what matters needing attention and other related information. in addition, we should remind everyone to pay attention to their own safety when playing herbicide in high temperature weather. Heatstroke must not occur.