Antibiotics are bactericidal substances produced during the metabolism of microorganisms, and have the effect of inhibiting the growth and development of other microorganisms and hindering their physiological functions. So far, there are more than 2,000 kinds of antibiotics found in the world, most of which are secretion products of actinomycetes, of which about 50 are used in medical and health, called medical antibiotics; more than 10 are used in agriculture, called agricultural antibiotics. Agricultural resistance. For example, streptomycin, jinggangmycin, endothelin, gentamicin, griseofulvin, cycloheximide, quercetin, etc., which are commonly used, are the main antibiotic varieties currently widely used.
The agricultural antibiotic has the advantages of high efficacy, strong selectivity, easy decomposition, low residual toxicity, safety to humans and animals, no pollution to the environment, wide source, simple method and easy promotion. Many countries now use antibiotics as an important means of combating diseases, insects and weeds. In recent years, China has made great progress in using antibiotics to control plant diseases and insect pests such as agriculture, forestry and flowers. If the insect is treated with neomycin, the concentration of 0.015% can kill 100% of the leaf curler within 3 days, and the mortality rate of the aphids on various forests is as high as 85% to 98%.
The use of agricultural antibiotics, according to different plant diseases, choose the appropriate method of medication. For plant diseases infested by soil, it can be used as soil disinfectant; for plant diseases infected by seeds and seedlings, it can be impregnated with antibiotics, such as soaking seeds, soaking roots, soaking seedlings, etc., or seedbed spraying; for some diseases of above-ground crops of agricultural and forestry crops, Plant spray can be selected at an appropriate time; it is used on fruit trees and is mainly used as an ointment to control bacterial ulcers. The concentration of the antibiotic applied is usually within 100 ppm, and rarely exceeds 200 ppm except for fruit trees and trees.
In order to improve the anti-bacterial effect of the antibiotic, a synergist and a metal ion are often added when the antibiotic is used. The addition of synergists promotes the spread and absorption of antibiotics. Commonly used synergists are glycerin and other polyhydroxy compounds. At present, 190 glycerin is added to agricultural antibiotic preparations which are generally commercially available. Polyhydroxy compounds have strong water absorption, which can prolong the effective absorption period of antibiotics, promote the hydration of the stratum corneum on the surface of plants, and enhance the water permeability of leaf surfaces. The addition of metal ions allows the antibiotic to form a complex, which significantly improves the efficacy. For example, the addition of 1% to 2% of copper sulfate to the compound endothelin can prolong the retention period of the agent in the plant and enhance the disease resistance of the plant. Several major agricultural antibiotics are now introduced as follows:
Streptomycin can be used to control bacterial diseases of crops by spraying with 50 to 100 ppm of liquid; bacterial soft rot can be controlled by spraying with 50 ppm of liquid; it can also be used to control bacterial diseases by immersing plant seeds with 50 to 100 ppm for 30 to 60 minutes.
Jinggangmycin can prevent root blight of melons and can be rooted with 20 to 100 ppm of liquid. The drug has strong systemic effect, and the drug has a long-lasting effect of 20 to 35 days, no phytotoxicity and low toxicity.
Griseofulvin to control melon wilt, 5% to 10% ointment can be used to coat the stem disease, once a week, a total of 3 to 5 times; control fruit rot disease, can be sprayed before 250ppm liquid.
Gentamicin is commonly used to control powdery mildew in wheat, melons and flowers, and can be sprayed with 50 to 150 ppm of liquid.
Actinomycin is also called Nongkang 101, and cherry leaf spot can be sprayed with 0.5 to 2 ppm liquid. The drug has strong systemic absorption and is long-lived in plants, which is prone to phytotoxicity. The drug is toxic to humans and animals and has a stimulating effect on the skin and mucous membranes. When used, it should not be mixed with alkaline pesticides .
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