Precautions for The Use of Herbicides in Maize Fields

There are two types of herbicide used in maize fields, pre-emergence herbicide and post-emergence herbicide. The efficacy of herbicides is affected by many factors, such as soil temperature, and humidity, soil texture, climatic conditions, human operation and etc. In general, the following precautions should be noted:

1. Before application, rinse the sprayer thoroughly to avoid residual damage.

2. Dilution method

Before spraying, the herbicide should be diluted firstly with warm water (30-40℃) into a mother liquor, then dilute again with cool water, so as to improve the effectiveness of the herbicide. Try not to mix the herbicide directly with cold water, otherwise, the effectiveness will be reduced.

3. Application timing

For pre-emergence herbicide, it’s better to apply it within 7 days after sowing before weeds come out. The ideal condition for application is on a windless day above 15 ℃, before 10:00 am or after 4:00 pm. If the temperature is low when spraying, the efficacy of the herbicide will be reduced. Do not apply the herbicide before heavy rain, so as to prevent the herbicide from seeping into the seed buds with the rain and causing phytotoxicity, which will further affect the emergence of seedlings.

4. Appropriate dosages

The application should follow the instructions on the label or the guidance from the local agricultural technician. Generally, the dosage should be reduced if apply on sandy land, otherwise increased in fertile land.

5. Post-emergence

Post-emergence herbicide should be applied in the 3-5 leaf stage of maize seedlings and the 2-leaf stage of weeds. If the effect on the subsequent crop is not considered, a mix of nicosulfuron and atrazine is recommended. In order to improve the efficacy of the herbicides, apply the same amount of product with more water at a rate of no less than 750 kg/ha.

Improper use of herbicides may cause phytotoxicity to maize, resulting in poor growth or deformity of corn. The causes of herbicide phytotoxicity in maize fields include:

1. Low temperatures. corn seedlings degrade herbicides slower and longer in low temperature, which is easier to cause phytotoxicity. 　　

2. Waterlogging. Phytotoxicity is more likely to occur when root vigor is affected by waterlogging.

3. Sprayer nozzle. Improper use of sprayer nozzles may cause phytotoxicity. Fan-shaped nozzles are preferable with less risk of phytotoxicity.

4. Overuse. Excessive use of herbicide can cause obvious phytotoxicity, and the effect on the subsequent crop cannot be ignored.

5. Herbicide-sensitive maize variety. Different maize varieties have different tolerances to herbicides. The tolerance of maize varieties to commonly used herbicides also needs to be considered when selecting maize varieties.

What can we do if phytotoxicity occurs in the maize field?

1. Proper management should be conducted without delay including, increasing the ground temperature, loosening the soil, enhancing the permeability of the soil, and increasing the vitality of the root system. 　　

2. Top dressing nitrogen fertilizer. 　　

3. Need to cut the heart leaves with severe phytotoxicity, then foliar spray herbicide antidote and fertilizers to reduce the negative effect of phytotoxicity no the plants.

King Quenson, Focus on Your Harvest!

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