Chemical control is a method of using chemical pesticides to control pests and weeds. This method has its advantages, that is, chemical pesticides can be produced on a large scale, spread widely in a large area, have a wide range of prevention and control, and have a quick effect, and have become an indispensable technical measure to prevent pests and weeds in agricultural production. However, chemical control has its own shortcomings. The long-term use of chemical pesticides alone has caused many side effects. For example, pests and germs produce drug resistance, and as a result the control effect becomes worse and worse. While killing pathogens and pests, it also kills natural enemies and beneficial animals of pests, destroys ecological balance, and causes some minor pests to become major pests. It is becoming more and more important. At the same time, it also pollutes the environment and contaminates vegetables. It directly threatens human health. Therefore, it is necessary to rationally use chemical pesticides. 1. Try to use pollution-free pesticides or high-efficiency, low-toxic and low-residue pesticides such as baking soda to prevent powdery mildew; Potassium permanganate can prevent vegetable virus disease; Thiabendazole (Tecdo) can control gray mold; Spray nitrogen solution (called nutrition control) can prevent downy mildew; aforeun EC can prevent root knot nematode disease and spotting, such as Liriomyza; Fu Xi Ling can prevent whitefly; anti-Bai Wei can control aphids; Diflubenzuron No. 3, inhibition CPIC , buprofezin, agrochemicals, kasik and other pesticides can control cabbage caterpillars, Plutella xylostella and other pests. 2. According to the law of occurrence of pests and diseases, timely application of vegetable diseases, generally in the early stages of drug use, if it is serious before the use of drugs, the effect is not good. Some diseases, such as gray mold, bacteria mainly infect the petals, followed by stigma, small fruit. According to the law of pathogenic bacteria infection, prevention and treatment advance to the flowering period, the effect is very good. Another example is the control of pests, generally according to the control indicators of medication, and Lepidoptera larvae, spraying before 3rd instar, otherwise the effect is poor. 3. Do not arbitrarily increase the concentration of the drug. The number of days between spraying should strictly comply with the general chemical prevention and control. Every 6-7 days should be sprayed with 1 dose, and the pest should be sprayed once every 10-15 days. Pay attention to the quality of spray and spray all parts. You can't miss it, especially the lower leaves. The front and back sprays are required to be sprayed on the opposite side of the leaves. They must not be sloppy, otherwise the effect is not good. When using 2,4-D anthrax flowers, special attention should be paid to the concentration. The concentration can not be large, nor can the flowers be repeated, otherwise the fruit Abnormalities occur. If you accidentally spray 2,4-D on the leaves, even if the concentration is small, there will be phytotoxicity and the leaves will become chicken feet. 4. To comply with the safety interval of pesticides because pesticides have residual problems, can not fight drugs today, vegetables will be harvested tomorrow, so in the vegetable harvest spraying pesticides should pay attention to safety intervals, different pesticides require different safety intervals . For example, the safety interval of quixphos pesticides is 14 days; the interval between zeslenium, mancozeb, and carbendazim pesticides is 15 days; dimethoate, trichlorfon, metalaxyl, triadimefl, 100 The interval between pesticides such as bacillus chlorophylla and chlorpheniramine was 7 days; the pesticides such as phoxim, dichlorvos, carbendazim, thiophanate and other pesticides were separated by 5 days; and the interval between phosphoaluminium pesticides was 3 days. 5, the protection of vegetables and more use of smoke or dust pesticides because of the protection of high humidity, while the use of smoke, dust pesticides to prevent pests and diseases without water, will not increase the humidity, the effect is good; cloudy, rainy days can be controlled, the effect Not affected. The spray liquid is different, must be selected sunny, otherwise the effect is not good. And the use of smoke or dust pesticides, labor, residue generally does not exceed the standard, in the protection of vegetables on the application of many advantages. 6. Look at the sky, see seedlings spray liquid generally used to choose sunny, no wind (or very small wind) weather. When the temperature is high, the concentration should be properly reduced to avoid phytotoxicity (especially protected vegetables). Some pesticides (such as some organic phosphorus) have higher efficacy when used at high temperatures. Seedling hours, the amount of liquid spray should be reduced, and the concentration should not be high, due to seedling tender and easy to produce injury. Some foods are sensitive to certain kinds of medicines, such as 50% of Triterpenes, used on cucumbers, 300 times fluids have phytotoxicity, 500 times fluids have no phytotoxicity, but 500 times fluids are used on Chinese cabbage to produce phytotoxicity. Therefore, the use of cabbage must be reduced in concentration, requiring more than 800 times. 7. Cannot blindly mix pesticides. Farmers often mix several pesticides together to save labor, consider the prevention and cure of various diseases, or prevent disease and pest control. The result is that some produce phytotoxicity and some fail (acid-base neutralization). ) Some of the toxicity increases, causing poisoning and even death. Therefore, it should be used scientifically. 8. Should pay attention to spraying safety when spraying, should wear masks, plastic gloves, goggles, mixing with hands is strictly prohibited. When there is something wrong with the sprayer, you can't bite it with your mouth and suck it with your mouth. After spraying, wash your hands with soap and water. If you have dizziness or nausea, you should stop spraying and rest in fresh air. If you are poisoned, you should go to the hospital for symptomatic treatment. Pesticides should be kept well. The used bottles should be buried deep and should not be used to hold other items. 9. To comply with laws and regulations for highly toxic pesticides, such as the 3911, Suhua 203, 1650, methyl 1605, 1059, killing Wei, Jiu Ling, phosphine, methylamine Phosphorus, isopropylphosphoric, trisphosphorus, omethoate, zinc phosphide, aluminum phosphide, cyanide, carbofuran, fluoroacetamide, arsenic, insecticide, celestris, salisan, ulcer net, chlorine Bitter, pentachlorophenol, dibromochloropropane, etc. And high residual pesticides, such as pesticides such as HCH, DDT, and chlordane, have been expressly stipulated by the state and are not allowed to be used on vegetables. However, some farmers still secretly used the 1605 control of leeks, the use of methamidophos to control the moth, and the use of carbofuran to control locusts. As a result, consumers consumed these vegetables and caused poisoning, resulting in serious consequences. 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