Selection and use of pesticides produced from pollution-free vegetables

1 Pesticide selection

1.1 Priority selection of biological pesticides

Bio-insecticides and acaricides commonly used in production: Bt, avermectin, Liuyangmycin, huaguangmycin, anisidine, rotenone, matrine, cucurbitine, etc.; fungicides: Jinggangmycin, Chunlei Taxomycin, polymycin, Wuyolin, agricultural streptomycin, etc.

1.2 Rational selection of chemical pesticides

First, it is strictly forbidden to use highly toxic, high-toxic, high-residue, high-bio-rich, high-grade (teratogenic, carcinogenic, mutagenic) pesticides and their compound preparations. Such as methamidophos, carbofuran, 1605, 3911, omethoate, insecticidal mites, chlorpyrifos, hexachlorocyclohexane, DDT, methylisophosphorus, aldicarb, methomyl, zinc phosphide, long-lasting effect Phosphorus, organic mercury preparations, etc. Some pesticide residues are large, such as dicofol, and its components are slowly decomposed. There is still residue in the crop after one year of application, and it is not suitable for use on vegetables. The second is to choose high-efficiency, low-toxic, low-residue chemical pesticides. The production of pollution-free vegetables allows the use of limited chemical pesticides. The quality of toxic residues in vegetables does not exceed the national sanitary standards, and the metabolites in the human body are harmless, easy to remove from the human body, and have little lethal effect on natural enemies. . The chemical insecticides and acaricides used are limited to trichlorfon, phoxim, dichlorvos, risperid, cypermethrin, deltamethrin, fenvalerate, ketone, diamethym, nisol, and蚜 fog, 太太保, chlorfenapyr, diflubenzuron, buprofezin and so on. Limited chemical fungicides: Bordeaux mixture, DT, killable, carbendazim, chlorothalonil, methyl thiophanate, dexamethasone, ethyl phosphine aluminum, metalaxyl, trisodium phosphate, etc.

2 pesticide use

2.1 the right medicine

On the basis of fully understanding the performance and use of pesticides; according to the types of pests and diseases, use appropriate pesticide types or dosage forms. For example, the stomach poison in the insecticide is effective in controlling the chewing mouth pests, and the prevention and treatment of the sucking mouthparts pests is not effective for the chlorpyrifos (the chlorpyrifos) has special effects on the white mites nymphs, but is ineffective against the mites; There are special effects, but the effect of preventing and treating melon is poor; metalaxyl is effective against various vegetable downy mildew, early blight, late blight, etc., but it is not effective against powdery mildew. In the prevention and control of pests and diseases in protected areas, different dosage forms of pesticides can be flexibly selected according to weather conditions. Sprays such as powders, wettable powders and suspensions can be used on sunny days. Tobacco sprays, dust sprays or smoked smoke should be used on cloudy days. Room humidity, reducing leaf dew and leaf edge spitting, has obvious effects on controlling low temperature and high humidity diseases.

2.2 Appropriate medication

According to the law of occurrence of pests and diseases, strictly control the best prevention and treatment period, and make timely use of drugs. For example, before planting or planting vegetables, measures such as shed room application and disinfection, soil treatment and chemical dressing should be adopted; when aphids and moths are in low density, the local application is applied. Different pesticides have different properties, and the control period is different. Biological pesticides have a slower effect and should be used 2 to 3 days earlier than chemical pesticides.

2.3 Scientific medication

It is necessary to pay attention to the alternate rotation of pesticides using different mechanisms of action, which cannot be singularized for a long time, preventing the resistance of pathogenic bacteria or pests, and is conducive to maintaining the control effect and service life of the medicament. In the early stage of vegetable growth, high-efficiency and low-toxic chemical pesticides and biological pesticides were mixed or alternately used, and bio-pesticides were mainly used in the late growth stage. The use of pesticides should promote low-volume spray methods and pay attention to uniform spraying.

2.4 Select the correct spray point or part

According to the occurrence characteristics of different pests and diseases in different periods, the different parts of the plants were used as targets for targeted application. To achieve the purpose of timely controlling the occurrence of pests and diseases, reducing the number of pathogens and reducing the number of insects, thereby reducing the use of drugs. For example, late blight usually occurs first on the front (south) crop of the shed, so it should be sprayed on the front crop in time. The occurrence of downy mildew is initiated by the lower leaves. The early control of downy mildew is focused on the lower leaves, which can alleviate the upper leaves. Pests such as aphids and whiteflies are inhabited on the back of young leaves, so they must be evenly sprayed, with the nozzles facing up and the back of the sprayed leaves.

2.5 Reasonable compounding agent

The method of mixed drug administration is adopted to achieve the purpose of controlling the pests and diseases of a plurality of pests and ones, but the pesticide compounding is premised on maintaining the original active ingredients or having synergistic effects, not increasing toxicity to humans and animals, and having good physical properties. Generally, neutral pesticides can be mixed; neutral pesticides and acidic pesticides can be mixed; acidic pesticides can be mixed; alkaline pesticides can not be mixed with other pesticides; microbial pesticides (such as Bt) cannot be combined with fungicides and Mixing strong pesticides; mixed pesticides should be used with mixing. When using various biological pesticides mixed with chemical pesticides, the chemical pesticides to be mixed can only be chemical pesticides that are allowed to be used.

2.6 Do not arbitrarily increase the amount of medication and the number of sprays

The guidelines for the safe use of pesticides and the standards for pollution-free vegetables stipulate the dosage, number of applications, maximum allowable residue and safe interval of each pesticide on different vegetable crops. It must be strictly implemented in the production of pollution-free vegetables. Increase the amount of medication and the number of sprays, a variety of pesticides chaos and chaos. The safety interval of pyrethroid pesticides is 5-7 days, the organophosphorus pesticides are 7 to 14 days, the fungicides are chlorothalonil, dexamethasone and carbendazim for more than 14 days, and the rest are 7 to 10 days. Pesticide blends perform a safe interval between the most residual active ingredients. After the vegetable spray, the pesticide must be degraded to no residual toxicity before it can be harvested. Vegetables that have been picked many times must be harvested after harvesting to ensure the health of consumers.
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