Five precautions for using herbicides in summer corn fields

The summer corn growing season coincides with high temperature and high humidity, and weeds in the field grow rapidly. In addition, with more rainfall, manual and mechanical weed control is relatively difficult and labor-intensive, so chemical weed control in corn fields is increasingly accepted and widely used by farmers. There are many types of corn herbicides with high application technical requirements, and improper use can cause phytotoxicity to corn. The following five points are precautions for using herbicides in summer corn fields:

First, after wheat harvest, if a large number of weeds have already grown in the field, a non-selective herbicide must be used. Glyphosate is a systemic herbicide, and no effect can be seen in the early stage after spraying, but after about two weeks, the weeds will die from the roots.

Second, pre-emergence herbicides that close the soil surface and prevent weeds from emerging include acetochlor-atrazine, Yucaojing, and Duatrazine, etc. Generally, 200 grams of formulation per mu is used, mixed with 45 kg of water, for good control efficacy. If the water volume is too low, the herbicide sealing layer will be thin, and some highly resistant weeds can easily break through the sealing layer, resulting in poor control efficacy. However, the water volume should not be too large either, otherwise the effective concentration of the herbicide will decrease and it will not provide a sealing effect.

Third, once the above pre-emergence herbicides come into contact with cotton, peanuts, soybeans, and vegetables, they will cause varying degrees of phytotoxicity. Therefore, when spraying the above herbicides, the following principles must be followed: spray as much as possible when there is no wind, and strictly prevent the herbicide from drifting with the wind onto vegetables, peanuts, and other crops; spray with the nozzle lowered to minimize herbicide drift; wear a protective hood in front of the nozzle and spray directionally.

Fourth, in recent years, because pre-emergence herbicides have had poor efficacy in some areas, some farmer friends simply wait until both corn and weeds have emerged, and then use herbicides such as Yunongle and Yuheng to control weeds. However, farmer friends should be reminded that the best period for control is when corn has 4~5 leaves and weeds have 3~4 leaves. If control is delayed until corn has 7 leaves, phytotoxicity may occur.

Fifth, when insect pests occur in corn fields, insecticides can be mixed with herbicides, but when using the herbicides Yunongle and Yuheng, they cannot be mixed with organophosphorus pesticides and can only be mixed with pyrethroid pesticides. The instructions should be carefully read during use.