In recent years, the application of herbicides has been rapidly developed, and has become one of the most important means of weed control in farmland in China。However, herbicides are a double-edged sword, and they also bring some negative effects in the process of use。Due to the characteristics and quality problems of herbicides, backward technology and poor environmental conditions, the problem of drug damage to crops has become increasingly prominent, and has become a major disease in the process of agricultural production and herbicide application, which seriously affects the benefit of agricultural production and the adjustment of planting structure。How to do if herbicide occurs？How to scientifically avoid herbicide harm？In this issue, we invite Professor Taobo of Northeast Agricultural University, who has been engaged in herbicide research for many years, to answer our questions in detail。
  特点
  Herbicide damage was increasing year by year
  After years of herbicide use in different areas of China, due to the relatively backward level of herbicide production and application technology, herbicide damage is relatively common, nearly 50% of the country's crop fields have different degrees of drug damage, and there is a trend of increasing year by year。It has seriously affected the benefit of agricultural production and the adjustment of planting structure, and has become a stubborn disease in agricultural production and herbicide application。
  Traditional long - lasting herbicides such as chlorsulfuron and oleosulfuron，Because the amount is decreasing year by year，There was a decreasing trend of the drug damage to the sensitive crops of the later stubble.New long residual herbicide，Such as flusulfonamide oxalone, methyl sulfoxone, azsulfursulfuramide, dichloroquinolinic acid and so on，The drug damage to the later crops increased year by year.Compound residual drug damage often occurs in soybean fields，Due to the continuous cropping of single crops in individual areas，The use of common drugs for years and the mixing of many drugs resulted in compound residual drug damage.Herbicide use is generally too high，The occurrence of crop drug damage increased year by year;The harm caused by the poor safety of some herbicides is also quite serious。
  There are differences in the occurrence of herbicides in different regions, and the northeast region is the region with the largest herbicide application amount in China. In the northeast region, the environmental temperature is low during the period of soil treatment of herbicides before crop sowing, crop growth is slow, and the ability to metabolize and detoxify herbicides is poor, so herbicide crop damage often occurs。In soybean fields in northeast China, acetochlor and other amide herbicides are easy to produce drug damage。The wheat fields in Shaanxi, Jiangsu, Sichuan and Hubei were susceptible to herbicide damage, and the later crops, maize and soybean were susceptible to herbicide damage.The cotton fields in Hubei and Hunan were susceptible to drug damage, and the early rice in Jiangsu, Zhejiang and Anhui were susceptible to residual drug damage.Acetochlor is one of the herbicides commonly used in maize and soybean after seeding in North China。Due to the persistent drought during the sowing of these crops in Inner Mongolia, Shanxi, Hebei and other places, the efficacy of the drug is not ideal in recent years。In order to improve the effect of weeding, farmers constantly increase the amount of acetochlor. Under the high dosage, after heavy rain, long-term low temperature and high humidity appear in the emergence process, which is easy to cause large-scale drug damage。
  类型
  Seasonal drug damage, residual drug damage, drift drug damage
  First, seasonal drug damage: such as soybean fields using fluosulfamide, acetochlor, azinoxone herbicide damage;Nicosulfuron, 2 were applied after maize field seedling，Drug damage of 4-D butyl ester (mainly manifested as maize deformity)，The heart leaf is whiplash，The tassels cannot be drawn out properly，Seriously affect the output);The different degree of drug damage caused by Dingpu mixture in rice seedling bed;And the blind use of unregistered herbicides on black bean, kidney bean and other bean plots;The herbicide containing Guangfenazole was used in peanut and mung bean fields to cause drug damage.Use wheat 3 before leaf stage or after jointing stage 2,4-D butyl ester and other causes drug harm。
  The second is residual drug damage: mainly in the soybean field using chlorsulfuron, flusulfonamide, imidazolethynicotinic acid, isoxalpine and other herbicides, resulting in subsequent sensitive crops such as corn, melons, potatoes, rice, sugar beet and other drug damage。In addition, low temperature and high humidity in spring, onion, melon, watermelon and other crops after transplantation often appear large areas of residual drug damage。
  The third is the drift of drug damage: the aerosol droplets volatilize and drift with the wind, resulting in the damage of sensitive crops in the vicinity, such as the use of 2,4-D butyl ester and isoxalone to the drug damage caused by nearby broad-leaved crops and trees。
  The general characteristics of crop damage caused by herbicides are as follows: the symptoms of conductive herbicide damage appear late, often the whole plant is damaged, and severe cases lead to no production, difficult to recover;Contact herbicide damage symptoms appear quickly and quickly, often crop local symptoms, if the growing point is not damaged, can be alleviated。
  原因
  70% of drug damage is caused by the use of technology
  First, the nature of the herbicide itself: poor safety, containing impurities or unqualified dosage forms, unreasonable formulation, excessive content, and the addition of illegal hidden ingredients。
  The second is the impact of environmental conditions: low temperature and rainy weather, windy weather or wrong time of application are easy to cause drug damage. For example, in May 2014, there were phased low temperature and rainy weather in Heilongjiang Province, and a large area of eluvial drug damage occurred in low-lying plots of soybean and corn fields and sandy loam plots。
  The third is the use of technology: long residual herbicides such as imidazolethynicotinic acid, chlorsulfuron produce drug damage to sensitive crops under low residual concentration;Excessive use of herbicides, misuse, mixing and improper selection of auxiliaries will also cause drug harm.Incorrect application period, incorrect application method, poor performance of application equipment, backward spraying technology, incomplete cleaning of sprayer and poor quality of field preparation also often cause drug damage。
  The fourth is crop factors: the difference of crop tolerance to herbicides (such as the difference of resistance of different rice varieties to paspalous), the difference of sensitivity at different growth stages, the difference of crop seedling quality and growth。
  Fifth, the history of drug use is not understood: the investigation found that with the large area of land circulation, land contractors do not understand the history of drug use of contracted land, often due to the use of long-term residual herbicides in the previous crop caused residual drug damage。
  According to the investigation, more than 70% of the damage caused by herbicides is caused by the use of technology。
  防范
  Scientific use of herbicides is particularly critical
  Before using the herbicide, the label should be carefully read to clarify the applicable crop, the appropriate application period and method, the object of control, the safe amount of the herbicide and the precautions to avoid using the wrong drug or beyond the scope of the drug, and avoid applying the drug outside the safe use period and over using the drug。Especially in the use of new herbicides, more careful, first small area test demonstration, and then large area application。
  Try to understand the characteristics of the herbicide used, the degree of resistance of the applied crop to the herbicide, and the possible influence of environmental conditions on it, so as to use the drug scientifically and accurately in all aspects of the drug。
  Different crops, the same crop in different growth stages or different growth states, the resistance to the same herbicide will also change。Only according to the time, place, type of medicine, crop growth conditions to ensure safety。
  The land is flat, the field plot should be intensively cultivated, there is no pothole phenomenon, in addition, the land gap is too large, resulting in the eluviation of the medicine to the roots of the crop, resulting in eluviation damage。The herbicide liquid should be mixed evenly and sprayed evenly. Before application, especially before the herbicide is mixed, the herbicide must be fully dissolved, and the herbicide should be stirred evenly by secondary dilution。When spraying in the field, it is necessary to walk at a uniform speed and spray evenly。Use safe and advanced herbicide spraying equipment to add spray additives。After applying herbicide, the sprayer should be thoroughly cleaned。
  The application of acetochlor in soybean field before seedling is safe for soybean, but after application, it is easy to cause soybean harm due to low temperature and rainy conditions, especially in low-lying plots prone to water accumulation。So the soybean field spraying acetochlor, need to consider the environmental weather factors。

Spraying atrazine on corn fields generally does not produce drug damage, but it will cause minor damage to corn when the amount of medicine is too large, so it should be strictly controlledPreparation dosage。