The Best Time to Weed Wheat and an Analysis of Common Misconceptions

Every year before winter or in spring, a large amount of weeds grows in wheat fields, seriously affecting the growth of wheat. For this reason, how to weed is the issue farmers care about most. So when is the best time to weed wheat? These misconceptions need attention!

1. When is the best time to weed wheat?

1. Before the New Year: during the wheat seedling stage (mid to late November)

2. After the New Year: during the green-up stage (late February to early March)

In addition, note that spraying is best done between 10 a.m. and 3 p.m., when the temperature is relatively higher.

2. Never fall into these 8 major misconceptions when weeding wheat fields

1. Do not apply herbicide before wheat has 4 leaves or after jointing

Most wheat field herbicides are applied after the 4-leaf stage and stopped at the jointing stage. Before the 4-leaf stage, wheat is relatively delicate, with low detoxification ability and immunity, and is prone to herbicide damage; after the jointing stage, wheat enters the booting stage, which is also the most fragile and critical period of its life. Applying herbicide at this time can very easily cause herbicide damage, sometimes causing the wheat ears to fail to emerge or to become deformed, seriously affecting the final yield. Apart from herbicides such as fluroxypyr, which can be used at half the rate after jointing, it is best not to try other herbicides!

2. Do not use herbicide when the average daily temperature is below 8 degrees

Except for a few herbicides (diflufenican, which is relatively tolerant of low temperatures), general herbicides have unsatisfactory effects in low-temperature weather and are prone to causing herbicide damage. Therefore, it is best to apply the product when the daily minimum temperature is above 8 degrees. The higher the temperature, the better the weeding effect, because weeds absorb light and grow vigorously, their stomata open, and they readily absorb water and the spray solution; the opposite is true at low temperatures.

3. Do not use herbicide in dry weather

When applying herbicide, in addition to considering temperature, you must also grasp soil moisture. In severe drought conditions, seize the opportunity when the wheat field is being watered and apply the pesticide in time to ensure the herbicide's efficacy. The efficacy of most herbicides requires a certain level of soil moisture; when soil moisture is 40%-60%, it is most favorable for the herbicide's efficacy.

4. Do not use herbicide when wheat seedlings are weak or roots are exposed

Generally, winter wheat fields undergo straw return, and the plots are relatively loose. If an abnormal weather year occurs (such as a warm, dry winter), the wheat roots may be unable to penetrate deeply because the soil is too loose, or part of the root system may be exposed. Such wheat is very prone to frost damage and water shortage, and is relatively sensitive and fragile. Applying herbicide at this time can easily harm the wheat.

5. Do not use herbicide when wheat is suffering from disease

In recent years, seed-borne or soil-borne diseases such as wheat sheath blight, root rot, and take-all have occurred frequently. Diseased wheat has extremely low resistance, and once herbicide damage occurs, it is not easy to recover. Therefore, for plots where wheat is seriously diseased, it is generally not recommended to use herbicides; give priority to treating the disease and strengthening the seedlings.

6. Do not use herbicide before and after heavy rain or before the arrival of cold air

Using herbicide before and after heavy rain or before the arrival of cold air affects the weeding effect on the one hand and can very easily cause herbicide damage on the other. The use of herbicides is prohibited under severe weather such as frost, rain and snow, hail, and cold waves. These all count as severe weather. In particular, herbicides must not be used in the 7 days before a late spring cold snap arrives. When using chemicals in winter, pay more attention to the weather forecast.

7. Do not apply herbicide within 7 days before or after using organophosphorus and carbamate pesticides

We all know that after applying organophosphorus or carbamate pesticides in corn fields, an interval of 7 days is needed before herbicide can be used, and after applying such insecticides in wheat fields, an interval of at least 7 days is also needed before herbicide can be used. Otherwise, it easily causes wheat to turn yellow and leaf burn. This is because organophosphorus pesticides reduce wheat's ability to degrade herbicides, and using herbicide immediately afterward easily leads to herbicide damage.

8. Do not spray twice over the same area or miss spots

When using herbicide, be sure to spray evenly. If there are missed spots or areas that are under-sprayed, the weeds receive uneven amounts of the chemical and the control effect will be poor; second, be sure not to spray twice over the same area, as this will cause wheat to turn yellow and easily cause herbicide damage.

3. What are the benefits of pre-winter weeding in wheat?

Pre-winter weeding in wheat refers to field weeding carried out before the Winter Solstice solar term (before wheat enters the overwintering period). It mainly has the following benefits:

1. The weeds are small and have poor resistance, which helps the chemical take effect;

2. The seedlings are small and easy to spray, with no overlapping between leaves, so the spray solution can reach the weeds, and less chemical and water are used;

3. It has no impact on the rapid growth of wheat seedlings after the New Year and is safe for the following crop.

The above is an introduction to the timing of wheat weeding and the misconceptions. We hope it is helpful to you!