How to prevent and control herbicides? What are the causes of herbicide phytotoxicity?

The current application of herbicides has become very common, with the attendant emergence of herbicides. According to statistics, nearly 50% of crop fields in the country have produced different levels of phytotoxicity, and there is a trend of increasing year by year, which has seriously affected the efficiency of agricultural production and the adjustment of planting structure, and has become a process of agricultural production and herbicide application. Stubborn.

The specific performance is as follows: traditional long-lasting herbicides such as chlorsulfuron-methyl and oil-sulfuron have a decreasing trend in the phytotoxicity of the susceptible crops due to the decreasing dosage; new long-term herbicides such as flufenazone , mesotrione, flufensulfuron, quinclorac, etc., the phytotoxicity caused by the crops after the crop has increased year by year;

Due to the continuous cropping of soybeans in some areas, the application of common drugs and the combination of various chemicals have caused compound residual phytotoxicity; the use of herbicides is generally too high, which makes the occurrence of crop phytotoxicity worse year by year; some herbicides have poor safety. The damage is also quite serious.

Causes of herbicide phytotoxicity

There are several reasons for the occurrence of herbicide phytotoxicity:

One is the nature of the herbicide itself. For example, the safety is poor, the impurities or the dosage form are unqualified, the formula is unreasonable, the content is too high, and illegal hidden components are added.

The second is the impact of environmental conditions. Low temperature and rain, windy weather or application period are not easy to cause phytotoxicity. For example, in rainy weather, soybeans and corn fields have leaching phytotoxicity in low-lying plots.

The third is the application technology. Long-lasting herbicides such as imidazolium and chlorsulfuron have phytotoxicity to sensitive crops at low residual concentrations; excessive application of herbicides, misuse, mixing and improper selection of auxiliaries produce phytotoxicity; incorrect application period, application The method is wrong, the performance of the application device is poor, the spray technique is backward, the sprayer is not cleaned thoroughly, and the quality of the field preparation is poor, resulting in phytotoxicity.

The fourth is the crop factor. Differences in tolerance of crop species to herbicides (eg different degrees of resistance of different rice varieties to Shakespeare), sensitivity differences in different growth stages of crops, crop seedling quality and growth differences.

The fifth is not to understand the history of the use of the field. With the large-scale land transfer, land contractors are often unaware of the history of the use of contracted land, often resulting in residual phytotoxicity caused by the application of long residual herbicides.

According to the survey, the herbicides caused by the application of pesticides accounted for more than 70%.

Type of herbicide phytotoxicity

First, the season's phytotoxicity. For example, herbicides in the soybean field are treated with fomesafen, acetochlor, and oxazin; the phytotoxicity of nicosulfuron and 2,4-D butyl ester in the corn field is mainly caused by corn malformation, heart The leaves are whip-like, and the tassels cannot be extracted normally, which seriously affects the yield);

Different degrees of phytotoxicity caused by application of Ding·Bao Mixture in rice seedbed; blind application of unregistered herbicides in soy bean plots such as black adzuki beans and cowpea; use of herbicide containing chlorhexidine for peanuts, mung bean fields, etc. Harmful; 2,4-D butyl ester was applied before or after the 3rd leaf stage of wheat to cause phytotoxicity.

The second is residual phytotoxicity. It is mainly used in soybean fields to apply herbicides such as chlorsulfuron-methyl, flufenazone, imidazolium, and oxacillin, which cause phytotoxicity in sensitive crops such as corn, melons, potatoes, rice and sugar beets. In addition, in the spring, low temperature and high humidity, residual crop damage occurred in crops such as onions, melons, and watermelons after transplanting.

The third is drifting physiology. The liquid droplets volatilize and drift with the wind, causing damage to nearby sensitive crops, such as the application of 2,4-D butyl ester and clomazone to the adjacent broad-leaved crops and trees.

In general, the symptoms of conductive herbicides appear late, often the whole plant is victimized, and severe cases lead to extinction and difficult to recover; the symptoms of contact-type herbicides appear faster and more urgent, often the symptoms appear locally in the crop, if growing points Unharmed, it can be alleviated.

How to prevent herbicide phytotoxicity

1. Before applying the herbicide, carefully read the label to clarify the applicable crop of the herbicide, the appropriate application period and method, the object to be controlled, the amount of safe medication and the precautions for medication, and avoid using the wrong medicine or over-the-range medication to avoid Apply medication and overdosage during safe medication. Especially when applying new herbicides, it is more prudent, first small area test demonstration, and then applied in large areas.

2. Different herbicides target different crops, such as butachlor and acetochlor, bensulfuron-methyl and chlorsulfuron, although they are only one word, one is applied in paddy fields and one is applied in dry fields. Even in the same crop, the herbicides applied are different at different growth stages or in different mantle (season) crops.

For example, when selecting post-emergence herbicides, some corn varieties are more sensitive to nicosulfuron, which is prone to phytotoxicity, such as Zhengdan 958 and Yuyu 22. Some products indicate that it is forbidden to apply on corn inbred lines, sweet corn, waxy corn and other varieties. Pay attention when choosing.

3. The herbicide liquid should be evenly mixed and sprayed evenly. Before the application, especially before the herbicide is mixed, the herbicide must be fully dissolved, and the herbicide should be evenly mixed by the second dilution method. When spraying in the field, you must walk at a constant speed and spray evenly. Apply safe and advanced herbicide spray equipment and add spray aid. After applying the herbicide, the sprayer should be thoroughly cleaned.

4. Some herbicides have a long residual period, which can lead to short seedlings, rotten roots or dead seedlings of the squat (season) sensitive crops. Therefore, when using herbicides, it is necessary to consider what crops are to be planted in the next season. For the following seasons, beet, potato, melon, sorghum, rice, cotton, vegetables, etc., it is not possible to use atrazine, chlorine. Umsulfuron, chlorsulfuron and the like as a herbicide for the last season crop;

When soy and wheat are planted, the application of the atrazine to the upper crop should be reduced by half. Different crops have different sensitivity to different herbicides. When selecting herbicides, we must pay attention to the impact on the lower and lower season crops.

5. Soybean field spraying acetochlor, pre-emergence application is safe for soybeans, but it is cold and rainy after application, especially in the field where the field is low and easy to accumulate water. Acetochlor can easily cause soybean damage. Therefore, the application of acetochlor in soybean fields requires consideration of environmental weather factors. Spraying atrazine in the corn field generally does not cause phytotoxicity, but it will cause minor damage to the corn when the dose is too large, so the dosage should be strictly controlled.

6. The field plots should be intensively cultivated, the land is flat, and there is no pothole phenomenon. In addition, the excessive gap of the land causes the liquid to leaching to the root of the crop, causing leaching and phytotoxicity.

This article is a large plantation reference WeChat subscription number released

This article URL: How to prevent and control herbicides? What are the causes of herbicide phytotoxicity?

Biochemical Pharmaceuticals

Injectable Insulin,Glutathione Lyophilized,Equine Tetanus Antitoxin,Tetanus Antitoxin Injection

NINGBO VOICE BIOCHEMIC CO. LTD , https://www.medicine-voice.com