Herbicides can effectively and rapidly control farmland weeds. In recent years, the application amount and application area have been continuously expanded and the effect has been remarkable. However, when it is used, it often causes various phytotoxicity to crops due to improper application, resulting in serious losses. In order to prevent and overcome phytotoxicity, we should pay attention to the diagnosis and use of herbicides. First, the symptoms of injury. The phytotoxicity caused by herbicides is variegated and diverse, similar to some disease symptoms, and often leads to cognitive errors in diagnosis. General drug injury is faster than disease symptoms and no pathogens appear. In the production, we should strengthen the identification of herbicide phytotoxicity. (a) Benzeneoxy carboxylic acids: Commonly used agents include 2,4-D, dimethyl tetrachloro, 2,4-dibutyl butyl. Symptoms are leaves, flowers, ear deformities. Leaves thick, dark green, curly, chicken-shaped or onion-like; crispy, easy to break, stem base swollen; roots short and thick, no root hair, plant short stature; severe growth, skin cracking, falling, falling fruit, and finally died . (B) aryloxyphenoxypropionic acid: commonly used agents have a stable kill, grass gram grass, Gai grass can, Wei Pa, hummer and so on. Symptoms are mainly plant malformations, growing brown and purple, or purple or yellow. (3) Diphenyl ethers: Commonly used pesticides include cis-ether, weeds, and tigers. Symptoms are brown necrotic spots on the leaves, severe leaf malformations, dry coking, and no new leaves. (4) Amides: Commonly used pharmaceutical agents include cable, dole, propanil, butachlor and others. Symptoms are yellowish when light, spots appear on heavy leaves, curls shrink, and finally die. (E) carbamates: commonly used agents are killing grass Dan, ragweed, oats fear. Symptoms are curly leaves, more tillers, shorter stem bases, new roots, and shorter plants. (6) Replacement of urea and trichlorobenzenes: There are mainly chlorotoluron, prometryn, and simazine. Mainly for chlorosis, the heart starts at the tip of the leaves and leaves, yellow is like a fire, plants are short, and growth is slow. (7) Heterocyclics: paraquat, glyphosate, legumeweed, oxazapine, and bentazone are the major ones. Symptoms are discolored leaves and yellow, and finally the plants die. Second, the prevention of phytotoxicity. In order to prevent improper use of herbicides and produce phytotoxicity, it must be strictly in accordance with the use of technology, standard operation. (a) Pay attention to herbicides and sensitive crops. Different crops are not sensitive to different herbicides. Herbicides that control broad-leaved weeds are sensitive to grass crops, while broad-leaved crops are sensitive to herbicides that control grass weeds. Such as 2,4-D, dimethyl tetrachlorine on cotton, melons, beans, fruit trees and other sensitive; Gai Cao, steady kill and so sensitive to wheat, rice, corn. Therefore, in use, we must look at the instructions, to understand the characteristics and performance of the removal of grass, pay attention to sensitive crops, beware of misuse or drug drift. (B) pay attention to crop sensitive period. Under normal conditions, crops are particularly sensitive to herbicides during germination, trifoliate, and filling stages, and are prone to phytotoxicity. (c) Strictly control the amount and concentration of herbicides. In order to prevent local herbicide damage caused by excessive herbicide dosage and concentration, the herbicide should be sprayed evenly when the herbicide is used. The walking speed, manual control of the width and width of the spray, and the speed must be uniform. The working time is not prolonged. (IV) Mastering the technical operating points of herbicides 1, "a level": The ground should be flat. The field of application of pesticides should be well-cultivated to ensure the formation of the ground, no large clods, no potholes. 2, "two uniform": the drug on the carrier should be mixed evenly, spray or poisonous soil should be uniform. 3. "Three standards": the time of application, the amount of pesticide application, and the area of ​​pesticide application area. For example, 40% oats were used to control wild oats. Before sowing, 3 kg/ha was used as medicine. 4, "four look": see seedlings, grass, weather, soil quality. For unrooted or thin seedlings, it is not easy to apply drugs: according to the type of weeds and growth conditions; when the temperature is low, the application amount is at the upper limit of the medication; the amount of the heavy and heavy soil is higher, the amount of the sandy soil is less; the soil is dry No medicine. 5, "five no": Miao weak seedlings do not pour; shallow paddy field water less than 3 cm or the depth of the flooded leaves do not apply the pesticide; soil is too dry to apply pesticides; when heavy rain or dew on the leaves do not apply; Rice paddy fields do not apply pesticides. (E) to master the performance of pharmaceuticals. Learn whether the drug is volatile, photolyzable, and susceptible to physical or chemical reactions in the soil. (six) clear "main attack site." Herbicides in the general soil treatment “main attack site†is just the germination of weeds, young stems and leaves and other parts, namely before the 3 leaves. While Sulfuronine is treated in stems and leaves during the weedy period, it is absorbed by stems and leaves and then transferred to other tissues. (7) The medication time is reasonable. For example, at the two-leaf stage of propofil, butachlor at 2-3 days before sowing, no traces of g and glyphosate increase with the increase of leaf area of ​​weeds. (h) Play the role of water. Western grass net, Goer, Da Zhuang, Nong Tzu, etc. to maintain the water layer after 4-6 cm, can play a role in efficacy, does not produce phytotoxicity; and kill grass Dan, weeding ether in the plot of water Produce phytotoxicity. (9) It is prohibited to use chaos. The combination of herbicides can increase the efficacy of pesticides and increase the spectrum of grass weeds. However, the combination of herbicides can lead to phytotoxicity. For example, dioscin can not be mixed with organic phosphorus or carbamate; dimethyl tetrachlorine can not be mixed with acidic pesticides. (x) Cleaning spray equipment. The herbicide sprayer used to clean, you can first rinse with water, then use soapy water or 2-3% alkaline water repeatedly washed several times, and then rinse with water. Third, overcome the harm of medicine. Once herbicides are used to produce phytotoxicity, effective measures should be actively taken to remedy the damages that may be caused to a minimum. (1) Detoxification: (1) When the medication is maximal, the field irrigation water should be immediately drained, irrigation should be performed several times with fresh water, and lime and other moderately acidic herbicides should be applied. (2) If there are many herbicides on the plants, they can be sprayed with mechanical irrigation water to reduce the toxic substances that stick to the leaves. (3) When a phytotoxicity occurs in some areas of the plot, first flush the water, plough it, replenish the seedlings, and then increase the available fertilizer. (4) If the plots are poisoned seriously, the plots should be exposed to sunlight, deep-frozen after leaching, and then planted after no impact, otherwise they will be flushed. Or plant a small amount of sensitive crops and observe for 10-15 days. (b) Strengthen field management. When the damage is light, timely topping or removal of the affected part, increase the quick-acting fertilizer, and reasonable irrigation; serious, plowing the land, replanting or replanting; for the cylinder grass found, can be applied to sub-fertilizer and Organic fertilizers can also be sprayed with dilute ammonia or 1% lime water and sprayed with hormone pesticides. (c) Application of plant growth regulators. Spray 4% gibberellin EC to promote crop growth. (d) Application of safeners. Safeners, also known as antidote, protect crops and detoxify a variety of herbicides. Such as using activated carbon to coat seeds or roots, stems, or even spread on the soil surface, can prevent Simazine from producing phytotoxicity to soybeans and wheat; indole dianhydride can prevent propylcarbamate such as propylcaprocarb to corn Phytotoxicity. Food Additives,Natural Food Additives,Food Additive Saccharin,Popular Food Additives SHANDONG BAISHENG BIOTECHNOLOGY COM , https://www.baishengbioproducts.com