Teasaponin, also known as tea saponin, has foaming, emulsifying, dispersing properties, and has the pharmacological effects of hemolysis, anti-osmosis, anti-inflammatory, phlegm and cough, analgesic, etc. It can be used to make various types of emulsifiers , Detergents, foaming agents, preservatives, insecticides and other agents, so it has a wide range of applications, including agriculture, detergents, medicine, building materials, aquatic products and cosmetics.
Camellia (Camelliasp.), such as Camellia oleifera (Camelliaoleifera) and tea (C.sinensis), are very rich in content. The saponin content of Camellia dregs remaining after squeezing the oil of Camellia oleifera seeds is about 5-14%. . Regarding the actual application of tea saponin in agriculture, the main application is the application of camellia meal (also known as bitter tea meal) or related products such as its extract. This article introduces the application and research of tea saponin in plant protection as follows, for farmers to refer to operations in the field.
Brief introduction of tea saponin and its effect on biology
Tea saponin is a secondary metabolite of plants. It has a defensive effect on viruses, bacteria, molds, protozoa, insects or herbivorous animals. Therefore, it exists in most plants and is a natural non-ionic surface activity. Agent, water-soluble. Tea saponin is easy to decompose in the environment and is relatively safe to humans and animals. However, it still has the risk of being toxic to other non-target organisms. It is especially toxic to most aquatic animals. It is recommended that operators use caution to avoid ecological damage. Cause excessive influence. Tea saponin is highly toxic to fish, has the effect of hemolysis and cell membrane destruction. It can enter the blood vessels of the fish by destroying the epidermal cells of the fish gills, causing the red blood cells to disintegrate and lose their activity, and finally lead to the death of the fish; however, for shrimps and crabs, Since the main components of the gill epidermis of shrimps and crabs are chitin and protein, which are different from the epidermal structure of fish gills, and saponin only has hemolytic effect on red blood cells, while the blood of shrimps and crabs is hemocyanin. The blood of vegetarian prawns and crabs does not cause hemolysis problems and is less toxic to them. For example, tea saponin at a concentration of 2.5 ppm can kill crucian carp, but this concentration is safe for prawns and crabs. Therefore, the extract of camellia meal can be used to remove harmful fish or trash fish in the process of shrimp and crab breeding, and the general application amount is about 5ppm. Saponin is also toxic to earthworms. If the earthworms are directly soaked in the saponin aqueous solution, the earthworms will secrete a large amount of mucus, gather into agglomerates, break, beaded, and have decreased peristaltic ability.
Research and Application of Tea Saponin in Plant Protection
1. Prevention and treatment of Fushou snails tea saponin has a good snail killing effect on Fushou snails, can inhibit the hatching of eggs of Fushou snails, and has a low half-lethal concentration (1.8mg/L) for the young snails within 24 hours. During rice transplanting, the oil camellia meal was sprayed in the field. The camellia meal must be sprayed in water to release the tea saponin, causing the death of the snails exposed to the tea saponin and effectively inhibiting the growth of the snails. The dosage is about 50 per hectare. -100 kg (Organic farming method can also be used, the application rate per hectare for organic cultivation should not exceed 50 kg). If the water depth is 3 cm and the tea saponin content is 5%-14%, the tea saponin concentration range is about 8.6- 48mg/L, it is toxic to snails and most aquatic organisms (fish, molluscs, amphibians). Therefore, farmers are reminded not to drain water for at least 2-3 days after spraying camellia dregs. The water should be drained after the tea saponin is naturally decomposed to reduce its impact on downstream aquatic organisms. In addition, most of the commercially available camellia meal contains water, and the amount of camellia saponin will decrease year by year with the length of storage time, and the snail-killing activity gradually fades. Therefore, it is recommended that the camellia meal should be used within 3 years after oil extraction. Snail effect.
2. Insecticide (repellent) scholars studied the relationship between tea plant diseases and insect pests and tea saponin, and found that tea trees with high tea saponin content are more resistant to bark beetles, while tea trees that are susceptible have lower tea saponin content. Other studies and literature also pointed out that tea saponin can be used as an insecticide or repellent to prevent and control plant pests. Its mechanism of action includes gastric poisoning, repellent, and clogging of the body surface after attachment to cause suffocation. It can also destroy the detoxification metabolic enzymes of the insects. Activity, which makes certain insects anti-feeding and affects their growth and development. For example, tea saponin has both gastric toxicity and repellent effects on the larvae of White butterfly larvae. The higher the concentration, the more significant the effect. When the concentration reaches 800mg/L, the 3rd, 4th, and 5th instar larvae have a strong dietary effect, which causes their growth and development to be slow, and the pupae are also smaller than those without food. It may also affect its nervous system, causing abnormal reactions such as tremor when the larvae feed; for Plutella xylostella, it mainly has a repellent effect and inhibits the growth and development of its larvae.
3. The antibacterial agent tea saponin also has bactericidal or bacteriostatic effects on plant pathogens, such as tea anthracnose or rotifer conidia, which can inhibit the germination of conidia, and can cause rice fever and rice flax leaf blight The pathogen, Alternaria spp…. and other pathogenic spores germinate abnormally, and inhibit the growth of the hyphae of Sclerotium sclerotium and Rhizoctonia solani, and it also has a strong toxic effect on soybean cyst nematode. In addition, there are also literatures published that tea saponin has a good control effect on various storage diseases such as citrus penicillium and green mold, and can be used for preservation and preservation of fruits after harvest. However, the current tea saponin preparations actually used in crop disease prevention and control still have considerable research and application space. Farmers can mix bitter tea meal as organic matter in the soil, and at the same time help reduce the damage of guava root nodule nematodes. Mainland China The report pointed out that in the 1950s, it used tea dry water (the main ingredient is tea saponin) to control rice fever and sheath blight.
4. Pesticide adjuvants or synergists According to the current research results, the application range of tea saponin in the pesticide industry includes as wetting agent and suspending agent, synergist and spreading agent, herbicide or slightly soluble in water Used as a co-solvent in pesticides; or directly used as biological pesticides. Because saponin itself has the characteristics of interfacial active agent, it can be mixed with pesticides, which can obviously improve the physical and chemical properties of the liquid medicine, and can be used as an auxiliary or synergist for the preparation of pesticides. The experiment by Wang et al. found that tea saponin can significantly reduce the surface tension of pesticide liquids. The author also observed similar phenomena in the field test. In this experiment, the water extract of suli bacteria mixed with camellia dregs was more adherent. Uniformity. The inference is that the moderate addition of Camellia dregs water extract can effectively increase the surface tension of the liquid, reduce the contact angle of the droplets on the target organism, and increase the effective deposition of the medicine on the target organism, which is conducive to the ability to adhere to the target organism. , So that the efficacy of the drug can be brought into full play. Increasing the dissolution and moisturizing effects of chemical agents may also be one of the mechanisms for improving the effectiveness of pesticides. Conclusion Camellia meal is a relatively cheap and natural by-product of oil extraction from Camellia oleifera. It is rich in tea saponin. In addition to being used as a natural cleaning agent, it is also recommended for farmers to use it to kill snails, prevent pests, and increase pesticides. The effect agent is mixed and applied. Although tea saponin is easy to decompose, and its efficacy is not easy to remain, it is highly toxic to earthworms and aquatic organisms. Particular attention must be paid to the dosage and usage when controlling snails in paddy fields to minimize the toxicity to other non-target organisms.
Concentration and effect of tea saponin
The 50% lethal concentration of the young snails of P. snails within 24 hours is low (1.8mg/L)
The concentration of tea saponin is about 8.6-48mg/L, which is toxic to snails and most aquatic organisms (fish, molluscs, amphibians)
Tea saponin has both gastric toxicity and repellent effects on the larvae of White butterfly, the higher the concentration, the more significant the effect. When the concentration reaches 800mg/L, the 3rd, 4th, and 5th instar larvae have a strong dietary effect, and cause their growth and development to be slow.
For Plutella xylostella, it mainly has a repellent effect and inhibits the growth and development of its larvae.
It has inhibitory effect on the spore germination of tea anthracnose or rotifer
It can make the pathogenic spores of rice fever, rice flax leaf blight, pear black spot… and other pathogenic spores germinate abnormally
Inhibit the growth of hyphae of Sclerotium sclerotium and Rhizoctonia solani
It also has a strong toxic effect on soybean cyst nematode
Post time: Oct-15-2021