1. Among the chemicals used to control fruit tree diseases, fungicides are the most widely used. Its prevention and treatment principles mainly include protection and treatment. Protection refers to spraying fungicides before the fruit trees get sick, preventing the invasion of pathogenic bacteria and protecting the fruit trees. This agent is called a protective agent, and its purpose is to reduce or eliminate the primary source of infection. It is widely used to spray drugs on plants growing in the field to form a film on the surface of plants, inhibit the germination of pathogenic spores or bacterial cells, or kill them, so that diseases cannot occur and spread. The characteristic of protective agent is that it can't enter fruit trees and is ineffective against invading bacteria. Therefore, in order to protect fruit trees, drugs must be used before the invasion of pathogenic bacteria. The spraying of chemicals should be even and thoughtful. Commonly used protective agents for fruit trees include Bordeaux solution, zineb, etc.
Therapeutic effect: When the fruit trees are infected, spraying drugs to prevent the disease from continuing to develop and even restore health is called therapeutic effect. This medicine is called a therapeutic agent. This kind of medicine has internal absorption, it can enter fruit trees, and even be conducted in fruit trees, killing germs or affecting the pathogenic process of germs. Commonly used therapeutic agents are carbendazim, tobrazine, chlorothalonil and so on.
Brief introduction and preparation of common fungicides.
(1) Bordeaux mixture is made of lime and copper sulfate with water. Taking the concentration of 1% as an example, it is made of 0.5 kg of quicklime, 0.5 kg of copper sulfate and 50 kg of water. Preparation method: First, dissolve 0.5 kg of copper sulfate in 25 kg of water in a wooden barrel (or cylinder), then dissolve 0.5 kg of quicklime (such as 32% of hydrated lime) into powder in a wooden barrel, and then add 25 kg of water, then pour the copper sulfate solution and limewater into a third wooden barrel at the same time, while stirring until the liquid medicine is sky blue. Bordeaux mixture can only be used together, not for a long time.
(2) Bordeaux pulp is made of 0.5 kg copper sulfate, 0.5 kg lime and 5 kg water. The preparation method is the same as Bordeaux mixture. In order to increase its adhesion, 0.23 kg of animal glue can be added to each kg of Bordeaux pulp.
(3) 6-6.5 kg of quicklime, 65,438 0 kg of original solution of mixed solution of stone and sulfur (20 Baume), 65,438 0 kg of salt and 33 kg of clear water are used as the white coating agent. Wet quicklime with a small amount of wet water first, and after it is digested or pulverized, add sulfur mixture and salt stock solution and mix with water.
(4) zineb Gong Shui Yuan powder is light yellow powder with rotten egg smell, and its dosage forms are 65% wettable powder and 80% wettable powder. The remaining period of the drug is about 7 days. Commonly used 500 ~ 800 times liquid.
(5) The sterilizing agent is gray powder with fishy smell and is insoluble in water. The dosage forms are 50% and 80% wettable powder, and the diluent is generally 500 ~ 800 times.
(6) The pure carbendazim is white crystal, and the dosage forms are 25% and 50% wettable powder. Commonly used 500 ~ 1000 times diluent.
(7) Tobuzin and thiophanate-methyl are colorless crystals. The dosage form of Tobuzin is 50% wettable powder, and thiophanate-methyl is 70% and 50% wettable powder. 50% thiophanate and thiophanate methyl are usually diluted 500 ~ 1000 times, and 70% thiophanate methyl is usually diluted 1000 ~ 1500 times.
(8) Pure chlorothalonil is white crystal, odorless and tasteless, and industrial products have pungent odor. The dosage form is 75% wettable powder, diluted 600 ~ 1000 times.
2. Chemical pesticides for controlling fruit tree pests are divided into:
(1) The contact killer is sprayed on the pests, permeates into the interior through the epidermis of the pests, kills the pests, or forms a tough film, closes the valve, and suffocates the pests. For example, pyrethrum, derris, nicotine and various oil emulsions are all contact killers.
(2) Stomach poison sprays medicine on the surface of plants, and pests will die of poisoning if they swallow the food with medicine. This medicine is called stomach medicine. Trichlorfon, dichlorvos, Nale, Marathon, carbaryl and chlordane are all stomach poisons.
(3) The internal medicine is absorbed and transmitted to all parts of the plant through roots, leaves or stems, and the pests are poisoned and die after feeding. This medicine is called systemic medicine. Phorate, desflutong, chlorpyrifos, dimethoate, phosphorus absorption, phosphorus trichloride and fluoroacetamide are all internal absorption agents.
(4) Fumigating agents use the steam of chemicals to kill pests. This medicine is called fumigant. Chloropicrin, hydrocyanic acid, methyl bromide and aluminum phosphide are all fumigants. Control of common fumigants for warehouse pests.
Pests occur, what pesticides are used to control them? It depends on whether the pest bites, drills or sucks plant juice. In the prevention and control of sucking insects, it is necessary to spray pesticides on pests, or absorb and transmit them to various parts of plants through roots, stems and leaves, so that pests can take poisoned contact pesticides and systemic agents. When controlling biting and drilling pests, it can be sprayed on the surface of food to exert its stomach toxicity, and at the same time it should be sprayed on pests to exert its contact killing effect.
Types of chemical pesticides:
(1) Inorganic pesticides Inorganic arsenic pesticides include arsenic trioxide, lead arsenate, calcium arsenate, etc. Inorganic fluorine pesticides include sodium fluoride, sodium fluorosilicate and barium fluorosilicate. Inorganic sulfides include stone sulfur mixture, sulfur barium mixture and so on.
(2) Organic pesticides generally refer to synthetic organic pesticides. Currently widely used mainly include:
Organophosphorus pesticides: they are often divided into two categories: high toxicity and low toxicity. Highly effective and highly toxic, such as 1605, 1059, Su Hua 203 and 39 1 1 (phorate). High efficiency and low toxicity such as trichlorfon, dimethoate, marathon, cartap, etc.
Organochlorine pesticides can be divided into two categories according to raw materials. One kind is the second, second and third kinds with benzene as raw material; The other is chlordane, heptachlor, mirex, aldrin, dieldrin, endosulfan and chlorobenzene, which are by-products of coking.
Carbamate insecticides: These compounds have the advantages of strong selectivity, quick response, short residual effect of most kinds and less residual toxicity. In recent years, due to the emergence of pest resistance and pesticide residues, such pesticides have developed rapidly abroad and occupied a very important position. There are more than ten kinds of this kind of pesticides, such as carbaryl, methomyl, propafenone, yechan powder, propoxur, fenobucarb, methomyl and so on.
(3) Botanical pesticides use some natural synthetic organic compounds contained in plants as pesticides. Most of these chemicals are non-toxic or slightly toxic to people and animals, which is safer for crops and has no residual toxicity. Such as tobacco, pyrethrum, derris, rhododendron, tripterygium wilfordii, tea seed cake, Stemona root, macleaya cordata, etc.
At present, the research on the synthesis of botanical insecticide, such as pyrethroid insecticides, permethrin, deltamethrin and S-5602, is under way at home and abroad. This kind of pesticide has the advantages of great insecticidal effect, low toxicity and easy decomposition into non-toxic substances in nature.
(4) Chemical sterile agent is a chemical agent used to reduce the reproduction of pests or reduce their population. Its characteristic is that it acts on the reproductive system of insects, making pests lose their reproductive ability. It can cause female infertility or male infertility, and can also cause male and female infertility at the same time. However, in practical application, there are still problems such as toxicity to beneficial insects, wild animals and plants, people and animals, which need further in-depth study. At present, there are many chemical disinfectants tested, among which tepa, metepa, thiotrpa, Territa and apholate are the most important.
(5) Sex attractants and sex pheromones Any chemical substance that can attract a large number of female and male insects is called a sex attractant. Such as methyl eugenol, can attract a large number of male Bactrocera dorsalis. Adult insects often secrete a pheromone (male or female), which can attract insects of the same sex to mate. This pheromone is called sex pheromone. Therefore, this sex pheromone is also a sex attractant. At present, the practical application of sex pheromone in pest control is to predict and verify the occurrence period, occurrence amount and damage range of short-term pests by using sex pheromone.
(6) antifeedant Application of antifeedant is another new way to control pests. Its function is not to kill pests directly, but to prevent pests from feeding and eventually starve them to death. The advantage of this method is that it does not kill natural enemies and other beneficial insects. Because of these advantages, antifeedant has become a good cooperative measure for integrated pest control. Triazene is the most studied antifeedant, and compound 24055 is the best one. It is harmless to most insects, but it can control chewing mouthparts pests, such as LEPIDOPTERA larvae, beetles, apple leaf rollers, pear fruit borers and so on, and has antifeedant effect.
Preparation of common pesticides in orchards;
(1) Stone Sulfur Mixture Stone Sulfur Mixture has a long history of controlling pests and diseases, and it is still a good medicine for controlling scale insects and mites. Preparation of lime-sulfur mixture: quicklime 1 (the amount of hydrated lime increases by 30%), sulfur powder 1.3 ~ 1.4, and water 13. Sulfur powder should be fine, lime should be pure, and fire should be strong. Cooking method: firstly, heat the water to about 80℃, pour the quicklime into the pot while it is hot, and after the quicklime is completely melted, add the sulfur iodine powder into the limewater and stir it while adding it. In the process of cooking, it is necessary to constantly stir and keep the heat. After 40 ~ 60 minutes, the solution gradually changed from yellow-green to reddish brown or brownish red. Finally, the liquid medicine is filtered to obtain a clear liquid, that is, the stock solution (mother solution) of the sulfur mixture.
(2) The pine alkali mixture is prepared according to the ratio of 3 parts of rosin (soil rosin), 2 parts of caustic soda and 0/0 part of water/kloc. First, crush rosin, boil 10 part of water in a pot, and then add alkali to the water. After the alkali is completely dissolved, slowly add the pre-pulverized rosin into the pot, stir while adding, and continue to cook, with strong firepower. In the process of cooking, if foam overflows, reduce the fire and cook for about 20 ~ 30 minutes until it becomes dark brown liquid. Finally, filter with gauze or brown to obtain mother liquor.
3. Newly developed pesticides
(1) New varieties of insecticides and acaricides Since 1980s, many new varieties of pesticides have been developed and applied, among which acaricide or acaricide-treated varieties account for a considerable proportion, while 73% and 57% of propargite, 20% of wettable powder and 15% of pyridaben are still widely used. 50% wettable powder, such as Torck, 20% fenpropathrin and its pyrethroid mixture, 5% pesticide, 5% pesticide (flufenoxuron), etc. , and many other new agricultural drugs have produced obvious resistance. Substitute varieties or promising varieties developed in recent years include the following.
①NI-25 3% EC and 20% soluble powder are newly developed pesticides by Japan Caotian Company, which have unique performance and broad insecticidal spectrum. At present, only aphids on apples and oranges are registered in China, which has excellent efficacy against aphids. The quick-acting persistence of 20 mg/l is much better than that of the famous variety omethoate 400 mg/l at present.
②20% imidacloprid SC was developed by Bayer Company in Germany. It is organic nitrogen, with broad insecticidal spectrum and systemic effect. 130mg/L has a good effect on citrus leaf miner, aphid, psyllid and so on.
③MTI-732 5% microcapsule suspension or emulsifiable concentrate. A new product of Mitsui East Asia Company of Japan, a new acaricide, has good quick-acting and persistent effect on panonychus citri and red mite, no phytotoxicity, safety to natural enemies and low dosage.
④ Mite 23% EC. The product of American Nongmenhaas Company is an insect growth regulator. Pests died early after use, and the control effect of Curculigo pests on fruit trees was remarkable, 64 ~128 mg/L.
⑤ Ankeding 20% EC, a product of Japan Dajia Group, a new carbamate product. Precursor containing carbofuran, internal absorption, broad spectrum. 10 mg/L was used to control apple yellow aphid, and the effect was good.
⑥ Domestic 20% diflubenzuron (40 ~ 66.7 mg/L) has control effect on citrus leaf miner and citrus rust mite. 25% diflubenzuron No.3 suspension concentrate, 125 ~ 166 mg/L, has good control effect on codling moth and citrus leaf miner. These two pesticides are both insect growth regulators, and their mechanism of action is to inhibit the chitin synthesis of insects through stomach toxicity, so that pests can not shed their skin and die. Therefore, its efficacy is slow, and it takes 3-5 days to get obvious effect, and its efficacy is close to or exceeds that of carmichael, so it is also one of the pollution-free pesticides.
There is also a new generation of dicarbamate pesticide Lavine 75% wettable powder from Rona Planck Company in France, which has a good control effect on resistant Lepidoptera pests. Bayer's Baishude 5.7% EC is cypermethrin, and its improved Bao Dao 2.5% EC is made of cypermethrin with the highest extraction activity. However, the development of resistance to cyhalothrin is slow, and it is more difficult for trans isomers to develop resistance. Therefore, this drug has a good control effect on Aphis citricola and Carposina persicae at 5 ~ 10 mg/L, and 3% EC with the highest active ingredient of cis-cypermethrin accounts for 98%, which can be used to control citrus leaf miner and Carposina persicae, and 15 ~ 30mg/L also has a good control effect on Litchi stem borer.
(2) Mixing insecticides and acaricides and mixing (compounding) pesticides are effective measures to improve the control effect, reduce the cost and delay the drug resistance of pests. This method has been adopted by scientific research and production departments at home and abroad for many years. However, many varieties developed in the past focused on synergy, ignoring the negative effects of increased toxicity. We should pay more attention to the balance between the two sides in the future. There are many kinds of mixtures developed in recent years, and here are only a few examples with good results.
① Control Panonychus citri, Panonychus citri and Tetranychus viennensis with chlorpyrifos (Tewei) 4 1.5% EC. Among them, the effect of rosol method is better, and chlorpyrifos can play a stable and lasting role, so 207 ~ 277 mg/L can play a better control effect.
② avermectin, propargite 13% EC, 130mg/L avermectin marathon 22.5%EC22/L can control citrus tetranychus citri for 20-30 days.
③ The mixture of fenpropathrin -S7 1639 and insect growth regulator has the same control effect on many citrus scale insects.
④ 50% EC and 333 ~ 500 mg/L mirex have good quick-acting effect on red spider of apple and peach fruit borer.
(3) New dosage forms of old varieties or new dosage forms Some old varieties that have been widely used abroad for many years and have good evaluation have also been introduced and popularized. Among them, because the carbon content of oil emulsion produced in Australia is much lower than that of similar products in China, it is not easy to cause phytotoxicity after use, which ensures its quality and reliability. Because the drug is safe to natural enemies, it has been fully affirmed to be used to control citrus scale insects and mites. It is 50 ~ 100 times that of controlling citrus tetranychus citri, and 0 ~/200 times that of controlling scale insects12 instar larvae, and can prevent female scale insects from laying eggs and hatching. Endosulfan is a well-known old variety. It is called Saidan in Germany, 35% EC, Indodan in India, Shuodan in Israel and Handan in Korea. It is an organochlorine pesticide, which has a good effect on preventing and controlling a variety of organophosphorus-resistant pests, such as aphids, tetranychus urticae, fruit eaters and so on. It is expected to become a better substitute if its residue determination is not beyond the standard.
(4) Due to the backward research and development of organic synthetic fungicides, the problem of drug resistance is increasingly prominent, which is obviously weaker than that of pesticides. First, there are few varieties. Except Bordeaux mixture, only some varieties of carbendazim, Tobezin, chlorothalonil and Dyson series are commonly used in fruit trees for many years. Second, the number is small. 1994 The consumption of various pesticides in China is about 200,000 tons, and fungicides only account for about 40,000 tons, accounting for 1/3 of pesticides. In recent years, about half of the fungicides introduced from abroad are used in fruits and vegetables, and copper preparations account for a considerable proportion. From the development and application of fruit trees, the role of copper preparation has become more and more important in recent two years. Only six foreign companies compete in China, and there are more domestic products. Other fungicides are mostly used for storage and preservation.
① Several copper preparations have been introduced and developed abroad, the main components of which are copper hydroxide, cuprous oxide, copper oxychloride, basic copper sulfate mixture or basic copper chloride mixture. The sterilization mechanism of copper preparation is mainly based on the fact that the tolerance of fungi and bacteria to copper ion is only 2 ~ 3 mg/L, while that of plants is 20 ~ 30 mg/L. Therefore, copper ion below 20 mg/L can inactivate intracellular enzymes of bacteria or fungi and sterilize, and the efficacy of divalent copper ion is higher than that of monovalent copper ion, but the proportion of divalent copper ion in the preparation should not be too high, otherwise phytotoxicity (such as copper sulfate) will easily occur. The rapid development of copper preparations in recent years is not only related to the low price, but also to the multi-point sterilization and the difficulty of drug resistance of bacteria.
Fenghuan: 77% wettable powder, a product of Germany Youleli Agrochemical Company. The effective component is copper hydroxide, the ratio of univalent copper to bivalent copper is moderate, the solubility is good, the crystal needle is fine, the surface area is large, and it covers the plant surface in a net shape. Therefore, the treatment and disease prevention effect is good, the dosage is small, it is safe for plants, resistant to rain erosion, and not easy to produce phytotoxicity (because it does not contain chloride ions). Control citrus canker 1500mg/L 1 ~ 2 times, and also control many diseases on apples.
Kocide 10 1: 77% wettable powder is a product of Goodwin company in the United States, and the active ingredient is copper hydroxide. This preparation has a unique dosage form. More than 50 kinds of plants have been registered for use in the United States, and they have been registered for use in citrus canker in China, and the actual promotion area of apples is also very large (but attention should be paid to the problem of phytotoxicity). 1994, they sold more than 250 tons in China. Citrus canker was sprayed with 1300 ~ 1900 mg/L for 2 ~ 3 times during the susceptible period.
Other copper agents and manufacturers include 77% crown fungus copper [Cu(OH)2] from Acto Company of the United States, 56% copper oxide from Sandoz Company of Switzerland, 84. 1% Haobaoduo (Bordeaux liquid powder) and so on. After many years of experiments and popularization, 30% copper oxychloride produced by Plant Protection Institute of Guangdong Academy of Agricultural Sciences is considered as a better variety to control citrus canker.
② Baikedu 40 wettable powder, produced by Dainippon Ink Chemical Industry Co., Ltd. The newly developed guanidine bactericide belongs to the same type of compound as Peifurong popularized in recent years, and has excellent effect on fungal diseases. 260 ~ 400 mg/L can control many diseases of apple, pear, peach, watermelon and other fruit trees, and the fresh-keeping effect of citrus treated at 400 mg/L can reach 98% during storage, which is better than Tektronix.
③ Anke 15% suspending agent, 50% suspending agent and 50% water-soluble powder, which are products of melamine company in the United States, are cinnamic acid derivatives and have good effects on downy mildew and epidemic diseases.
④ Anti-virus Alum 64 wettable powder, a product of Sandoz Pesticide Company of Switzerland. It is a mixture of 8% copper oxazolidine and 56% mancozeb. Very low toxicity to people and animals, not easy to cause phytotoxicity, and has both internal absorption and contact killing effects. It is specially used for mold and pythium.
(5) preservative for fruit storage:
(1) Vanderbilt 50% EC, mackesey Company; Daikemei 25% EC from Daikemei Company of America; Baikedu 40 wettable powder is used to control Penicillium and Penicillium citri.
② 50% wettable powder (mixture) and 25% emulsifiable concentrate, 250 ~ 1000 mg/L, produced by Germany Aigefu Company, were used to control Geotrichum diseases of citrus, banana, mango and litchi.
③ Perricord, Ethazol and Swiss Cibajaji products were used to control litchi acid rot.
The use of highly toxic pesticides must be carried out in accordance with the safe operation procedures. It is necessary to strengthen the storage work, focusing on locking and storing in special warehouses, and appointing special personnel to be responsible. Empty bottles shall be returned for centralized treatment and shall not be used for other purposes. Toxic pesticides should not be used to control fruit tree pests. Generally do not use it within one month before harvest. Protection should be strengthened in the process of dispensing and spraying. Do not touch the skin with stock solution and liquid medicine. If there is, wash it with soapy water immediately. Don't drink. Wear a mask to prevent inhalation of medicine mist and gas. Custody, medicine, spraying personnel should be designated by special personnel, and should organize the study of anti-virus and detoxification knowledge. If symptoms of poisoning are found, detoxification measures should be taken immediately and sent to hospital for treatment and rescue if necessary.
The problems in chemical prevention and control have gradually emerged since the 1950s, which has attracted people's attention. Mainly due to the long-term continuous application of a large number of pesticides, agricultural products, air, soil and water have been polluted, threatening human health. Some pesticides, especially broad-spectrum pesticides, kill both pests and their natural enemies. In particular, continuous application of a single pesticide will cause pests to develop drug resistance, which will bring difficulties to control. Therefore, it is necessary to fully grasp the occurrence and development law of pests and diseases, make predictions and choose favorable opportunities for prevention and control, such as LEPIDOPTERA pests. Because adults are harmless and eggs don't eat, preventing larvae is better than preventing adults and eggs. Larvae 1 ~ 3 instars eat very little, and the food intake of the first 3 instars generally accounts for only 3% ~ 5% of the whole life, which is very harmful and weak in drug resistance. Therefore, the favorable period for controlling larvae is generally before the 3rd instar, but the favorable period for controlling stem borers should generally be from the spawning period to the larval incubation period, so as to prevent adults from spawning or migrating. Pick and treat pests and diseases in the diseased spot stage, and don't blindly spray drugs regularly or increase the concentration of drugs at will regardless of the number of natural enemies. Therefore, it is considered that the principles of using pesticides in integrated orchard control are: those that can be treated selectively should not be treated universally; Those who can treat both, not specialized; If microbial pesticides can be used, chemical pesticides are not needed; Those that can be controlled by selective, low-toxic and low-residue pesticides need not be controlled by broad-spectrum, high-toxic and high-residue pesticides; Can be used alone, not mixed; You can use a low dose, not a high dose. Do "control poly" and give play to the two beneficial effects of biological control and chemical control.