When is the best time to apply herbicide to corn?

Weeding crops is a common task in agricultural production, so when should herbicide be applied to corn? Which chemicals can be used?

When should herbicide be applied to corn?

Before planting corn, a pre-emergence herbicide should be applied to kill weeds that have not yet emerged; then wait until the corn is at the 2-5 leaf stage before applying herbicide, which can help avoid herbicide damage. In addition, the best time of day to apply herbicide is after 5 p.m., and spraying should be avoided in the morning when there is dew, to prevent herbicide damage.

Which chemicals can be used for weed control in corn?

1. Topramezone

Apply at the 2-4 leaf stage of corn seedlings and the 2-5 leaf stage of annual weeds. It can effectively control annual monocotyledonous and dicotyledonous weeds. It is safe for corn and also safe for sweet corn and waxy corn. It has very good compatibility and activity with atrazine; adding atrazine can improve its activity against large weeds and Asiatic dayflower, and increase its speed of action.

2. Carfentrazone-ethyl

It is not sensitive to corn varieties, is safe, has a good effect on broadleaf weeds, and acts quickly. It has excellent control efficacy against weeds that have developed resistance in areas where sulfonylurea herbicides have been used for a long time, and it is safe for subsequent crops. When used for post-emergence weed control in corn fields, mixing it with nicosulfuron can broaden the weed control spectrum and also enhance efficacy.

3. Fluroxypyr

It has good systemic activity, strong selectivity, and notable control efficacy. It is safe for corn, and its targets are difficult-to-control perennial broadleaf weeds such as field bindweed and alligatorweed. It is relatively safe for corn, but it is difficult to promote as a single agent, so it is recommended to mix it with nicosulfuron, which can broaden the weed control spectrum and improve efficacy.

4. Nicosulfuron

It is suitable for corn, including dent corn, semi-dent corn, and flint corn. It mainly controls annual grass weeds and some broadleaf weeds, and is currently one of the sulfonylurea herbicides that is highly effective against grass weeds. Its advantages include: a broad weed control spectrum, good and stable efficacy, killing weeds including their roots, low requirements for soil and climate, a relatively long application period, and safety for known corn varieties.

In addition, dicamba, bromoxynil octanoate, diquat, glyphosate ammonium salt, glyphosate potassium salt, glyphosate isopropylamine salt, and so on can all be used to control weeds in corn. However, different chemicals target different weeds, so everyone should pay attention to identifying them.