|Abamectin Chemical Properties|
|Abamectin Usage And Synthesis|
|Bio-pesticides||Avermectin is a kind of 16-membered ring macrolide compound which was first developed by the Kitasato University in Japan and Merck Company (United States). It has insecticidal, acaricidal, and nematicidal activity. It is produced by the fermentation of Streptomyces avermitilis. Natural avermectin containing eight component with four major components namely A1a, A2a, B1a and B2a with the total content being ≥80%; another four components corresponding to smaller proportion are A1b, A2b, B1b, and B2b with the total content of ≤20%. Currently commercialized avermectin pesticide has abamectin as the main insecticidal ingredient (Avermectin B1a + B1b with B1a being not less than 90% and B1b being less than 5%). It is calibrate by the content of B1a. Since 1991 when abamectin had entered into the market of pesticides in China, avermectin pesticide has played an important role in the pest prevention and control system of China. Avermectin is currently produced by over tens companies in China with the currently marketed avermectin series pesticides including abamectin, ivermectin and emamectin benzoate. In the late 1980s, Shanghai Institute of pesticides of China has isolated and screened the 7051 strain from Guangdong Jieyang soil. Identification analysis had proved that this strain is quite similar with S.avermitilis Ma-8460 and can produce a compound with the same chemical structure as avermectin. In 1993, the new technology Development Corporation of Beijing Agricultural University had initiated research project for development and production of this drug. Avermectin is a new class of antibiotics characterized with a novel structure and dual application to both crops and livestock. With the improvement of people's living standards as well as the demanding for green good, bio-pesticides is quite preferred in current pesticide market. According to the pundits’ prediction, the 21st century will be the century of biological pesticides. It is reported that the European bio-pesticides sales increased from 100 million dollar (1997) to 160 million dollars in 2004. Avermectin is the most popular and highly competitive novel biological pesticide in currently bio-pesticide market.
|Active Pharmaceutical Ingredient||Avermectin has its original drug be white or yellow-white crystalline powder with an active ingredient content being 75% to 80%, specific gravity being 1.16, melting point being 155 ~ 157 ℃, and vapor pressure being 2 × 10-7pa. At 21℃ It has a solubility being 7.8 g / liter in water, 100 mg/mL in acetone, 20 mg/mL in ethanol, 19.5 mg/mL in methanol, 10 mg/mL in chloroform, 6 mg/mL in ring hexane, 70 mg/mL in isopropyl alcohol, 0.5 mg/mL in kerosene, and 350 mg/mL in toluene. At room temperature is not easy to be decomposed. At 25 ℃, no decomposition is observed for its solution of pH6 ~ 9. |
The Appearance of its preparation is light brown liquid. Its preparation can be stored stably at room temperature for more than 2 years.
Toxicity: According to Chinese pesticide toxicity grading standards, avermectin belongs to highly toxic pesticides. For original drug; acute oral-rat LD50: l0 mg / kg; acute oral-mice LD50: 13 mg/kg; acute percutaneous administration-rabbits LD50: greater than 2000 mg / kg; acute percutaneous administration-rat LD50: greater than 380 mg / kg; acute inhalation-rat LC50 greater than 5.7 mg / liter; It has no skin irritation effect but with slight stimulus on eyes. It has no teratogenic, carcinogenic, and mutagenic effect on animals within experimental dose. For three generations of breeding experiments in rats, the non-effect dose is 0.12 mg / kg / day. For rats in two years, the non-effect dose in rats is 2 mg / kg / day. It is highly toxic to aquatic organisms. Trout-96 hours LD50:3.6 mg /l; bluegill sunfish-96 hours LC50: 9.6 micrograms/liter. It is also highly toxic to bees, oral-LD50: 0.009 g / head, contact-LD50: 0.002 g / head; However, the LT50 of its residue in the foliage is 4 hours. After 4 hours, the residue drug in the foliage agent is of low toxicity to bees. It has low toxicity to birds; quail, acute-oral LD50: greater than 2000 mg / kg, ducks, acute-oral LD50: 86.4 mg / kg.
For the preparation, rat acute-oral LD50: 650 mg / kg, rabbits acute-percutaneous LD50: greater than 2000 mg / kg. Rat acute-inhalation LD50: 1.1 mg/liter. It has irritation effect on eye and skin.
Its preparation is 1.8% Avermectin EC (18 g active ingredient contained per liter)
|Action property||Avermectin has stomach poisoning effect and contact-killing effect ton mites and insects but can’t kill the eggs. Different from common pesticide, it has a unique mechanism of action through interfering with neuro-physiological activity, stimulating the release of γ- aminobutyric acid which has inhibitory effect on nerve transmission of arthropods. Adult mites, nymphs and insect larvae get paralysis upon contact with avermectin with being inactive, non-feeding and being dead after 2 to 4 days. Because it does not cause rapid dehydration of insects, so avermectin has a relative slow lethal effect. Though avermectin has direct contact killing effect on predatory insects and parasitoid, due to its small residue in plant surface, it has little damage to beneficial insects. In the ground, avermectin is not mobile due to the soil adsorption and can be broken down by microorganisms, and therefore has no cumulative effects in the environment which can be used as a part of comprehensive prevention and control. It can be easily prepared. Pour the preparation into the water and slightly mix after which it will be ready for using. It is also safe for crop without causing any damage according to the introductory manual. It is suitable for crops such as vegetables, citrus and cotton. |
Control object: it has unique efficacy in antagonism pests such as diamondback moth, leafminer, and spider mite.
Applications: avermectin has stomach poisoning effect and contract-killing effect on mites and insects with a strong penetration capability. After being sprayed into the leaves, it rapidly infiltrate into mesophyll to form numerous miniature anther sac. Upon eating or contact the drug liquid, the adult mites, nymphs or insect larvae can quickly get paralysis symptoms with being inactive, non -feeding, and will be dead after 2 to 4 days. The avermectin residues amount in foliage is very low and can also be quickly decomposed into non-toxic substances, therefore causing a little damage of natural enemies. Avermectin has no ovicidal effect.
For applying avermectin for control of mites such as red spider and rust spiders, use 3000-5000 times diluted 1.8% avermectin solution or adds 20 to 33 mL of 1.8% avermectin per 100 liters of water (effective concentration of 3.6 to 6 mg / L). For the control of diamondback moth and other Lepidoptera larvae, use the 2000 to 3000-times diluted 1.8% avermectin or add 33 to 50 mL of 1.8% avermectin per 100 liters of water (effective concentration of 6 to 9 mg / L) for spray. It can give the best efficacy upon drug application in the beginning of larvae hatch with supplying milli dry vegetable oil being able to increase the efficacy.
For spider mite control in cotton field, apply 30 to 40 mL of 1.8% Avermectin EC per acre (active ingredient from 0.54 to 0.72 g) can have a duration time up to 30 days.
The above information is edited by the Chemicalbook of Dai Xiongfeng.
|Precautions||1. Avermectin has a slow insecticide, acaricide action with the number of dead insects reaching peak after three days. However, its application can immediately cause the feeding stop and spread of the pests. |
2. Avermectin is highly toxic to fish, so avoid the contamination of rivers, ponds when spraying. Avoid spraying upon the foraging period of honeybees.
|Poultry anti-parasitic drugs||Avermectin tablet |
Specifications: 2mg / sheet
For the treatment of various kinds of nematodes, ticks, mites, fleas, lice and flies of horses, cattle, sheep, pigs, dogs, cats and other poultry both in vivo and in vitro.
Oral absorption for horse has a high efficacy (killing rate being 95% to 100%) on large round worm (common round worm, horse round worm, round worm without teeth), roundworm (Parascaris equorum), Enterobius (Oxyuris equi), stomach worms (Grand discreet Rasi nematodes, Hebronema nematodes), intestinal nematodes (trichostrongylus axei, Strongyloides), lung nematodes (dictyocaulus arnfieldi) and other adults worm and larvae).
Oral or subcutaneous administration of avermectin for cattle, sheep has a high killing rate (97% to 100%) on Haemonchus, Ostertagia, Cooperia, Trichostrongyle (Trichostrongyle axei), round worm, Bunostomum, Nematodirus spp, Trichuris, Dictyocaulus, Chabertia ovina imago and 4-phase larva.
Oral administration or orally administration together with spice; the amount per time:
1. horses, cows, donkeys, mules, and sheep: take 1 tablet per 10kg of body weight.
2. pigs, fox, dogs, and cats: take 1 tablet per 6 kg of body weight; for treatment of Demodex canis, take one tablet per 3 kg of body weight; take continuously for five times at the interval of seven days.
3. chickens, ducks, geese, rabbits, and pigeons: take 1 tablet per 6 ~ 8 kg weight.
|Analysis Methods||High Performance Liquid Chromatography.
|Characteristics of avermectin series agents||1. broad spectrum insecticide|
The current reported insecticide spectrum of avermectin contains 84 species. In China, it is mainly used for control of pests with small body, multiple generations and being prone to become drug-resistant such as pear psylla, and cotton aphid, leaf mining pests such as the Inter-American Blanchard, pest mites such as Tetranychus urticae, Calacarus carinatus Green, Tetranychus viennensis and pests with wide range of hosts and miscellaneous eating habits such as Plutella xylostella.
2. the unique mechanism of killing pests
Avermectin is a nerve toxic agent. Its mechanism is targeting to the GABAA receptor of insect neuron synapse or neuromuscular synapse, interfering with the information transfer of nerve endings, namely stimulating the nerve endings to release neurotransmitter inhibitor γ -aminobutyric acid (GA-BA), prompting the extensive opening of the GABA-gated chloride channel with chloride channel-activating effect. In this case, large influx of chloride ions cause nerve membrane potential being hyperpolarized, resulting in the inhibition of the nerve membrane, and thereby blocking the contact between nerve endings and muscle, thus causing insect paralysis, poor feeding, and death. Because of its unique mechanism of action, it has no cross-resistance with commonly-used agents. According to reports, in addition to GABA receptors controlled chloride channels, avermectin can also affect other ligand-controlled chloride channels. For example, Ivermectin can induce the irreversible increase of membrane conduction of muscle fibers (non GABA innervations) of locust.
|Excellent stratification flow activity||Stratification flow activity refers to that: after its spray, avermectin can penetrate into the leaf tissue and form a drug sac inside epidermis parenchyma cells for long-term storage, so avermectin has good persistence. Because of its good stratification flow activity, avermectin has good efficacy on killing pests such as pest mites, leaf miner flier, leaf miner moth and other borer pests or sucking insects that are difficult to be prevented and treated with common drugs. Avermectin is easily biodegradable in soil and water and can be absorbed by the soil without leaching and residue and do not pollute the environment; it also has no accumulation in vivo and no residual accumulation and persistence, and thus avermectin should belong to pollution-free pesticides. Avermectin can also be broken down by the soil bacteria into derivatives having higher activity such as the insecticidal activity of plant nematodes.
|The current status and countermeasure of organism resistance to avermectin||There are many foreign studies regarding to the organism resistance and resistance mechanism on avermectin. In 1980, Scott and Geoghiou had first discovered anti-pyrethroid indoor resistant-selection housefly strain (LPR) has 7.6-fold cross-resistance on abamectin. Further study showed that this phenomenon is due to the increased metabolism of multi-function oxidase (MFO) and reduced skin penetration with reduction of the skin penetration as the major resistance mechanism and is highly recessive inheritance. In 1991, Gampos and Dybas had discovered that two-spotted spider mites are resistant to abamectin with its resistance being also related to epidermis penetration and oxidative metabolism, and the development of the resistance of two-spotted spider mite to Avermectins is related to the duration of medication. Its resistance genetic is incomplete autosomal recessive inheritance. During the study on drug resistance selection of diamondback moth, Li Tengwu et al have found that genetic resistance to abamectin in Diamondback Moth is also incomplete autosomal recessive inheritance. Argentine and Clark has discovered the resistance of potato beetle on Abamectin with the mechanisms also being related to multi-function oxidase and carboxylesterase with its resistance heredity being similar to diamondback moth and T. urticae, namely also belonging to autosomal incompletely recessive inheritance. It has found that clover leaf miner, diamondback moth, and German cockroach also have certain resistance to abamectin.
|Toxicity||CF mice acute-oral LD50: 13.6 ~ 23.8 mg/kg, CRCD mice: 10.6 ~ 11.3mg / kg, CRCD neonatal rats: 1.52mg / kg. The minimum dose for causing effect is: CR: CD neonatal rats daily: 0.12mg / kg, CRCD rats daily: 2.0mg / kg, Beagle dogs daily: 0.5mg / kg, monkeys daily: 2.0mg/kg. Rabbit, acute-percutaneous LD50> 2000mg/kg; Rats continuous administration: 8 weeks, the mice continuously administered: 94 weeks, non-effect daily dose: 4mg/kg, 2-year feeding rat, non-effect dose of 2mg/kg. Teratogenicity has showed that the non-effect dose of maternal toxicity in rats was 0.05mg / kg, and in mice was 1.6mg / kg. Ames test has showed that there was no genetic toxicity and no carcinogenic effects. Trout LC50: 3.2μg/L, carp LC50: 4.2μg/L, Daphnia LC50: 0.34 μg/L, diphtheria quail LD50: 2000mg/kg, ducks acute-oral LD50: 86.4mg/kg. Bees oral, LD50: 0.009μg; contact, LD50: 0.002μg / only.
|Chemical Properties||It has an appearance of being light yellow to white crystalline powder. It is odorless with the m.p. being 155 ~ 157 ℃, the vapor pressure being 2X10-7Pa, and the relative density being 1.16 (21 ℃). Solubility at 21 ℃: Toluene 350g / L, acetone 100g / L, isopropanol 70g / L, chloroform 25g / L, ethanol 20g / L, methanol 19.5g / L, cyclohexane 6g / L, kerosene 0.5g / L, water 10μg / L. Partition coefficient: 9.9 × 103. It is stable under normal conditions with no hydrolysis upon pH value being 5 to 9.
|Application||It is a kind of 16-membered macrolide, farm-livestock dual antibiotics with strong insecticidal, acaricidal, nematicidal activity. It is of broad-spectrum, high efficiency and safety. It has strong stomach poisoning and contact-killing effect without being able to kill the eggs. Its mechanism of action is interfering with the neuro-physiological activity, affecting the transmission of cellular membrane chloride with GABA being the target site. When the drug stimulates the target sites, it can block the transmission process of motor nerve information, resulting in the signal of central nervous systems of pest being continuously received by motor neurons, causing rapid paralysis of pests within hours, poor feeding, and slow moving or not moving. Because they do not cause rapid dehydration of insect rapid dehydration, so the lethal effect is slow. They will generally die after 24d after. It is mainly used for the prevention and treatment of various kinds of pests such as diamondback moth, cabbage caterpillar, armyworm, and flea in vegetables or fruit trees, it is particularly efficient in treating insect pests resistant to other pesticides. The amount per hectare for treating vegetable pests is 10 ~ 20g with control efficiency of over 90%; for the control of citrus rust mite: 13.5 ~ 54g per hectare with residual time being as long as 4 weeks (reduce the dose to 13.5 to 27 g upon being mixed with mineral oil by which the residue time can be extended to 16 weeks); it can be used for control of carmine spider mite, tobacco budworm, bollworm and cotton aphid with good efficacy. In addition, it can also be used to control cattle parasitic diseases, such as Damalinia bovis, Boophilus microplus, and bovine foot mite. When used for the control of parasitic diseases, the dosage is 0.2mg / kg of body weight. |
It has driving and killing effect on nematodes, insects and mites. It can be used for the treatment of nematodes disease, mite disease as well as parasitic disease of livestock and poultry.
It has good control efficacy and delayed resistance for various kinds of pests of citrus, vegetables, cotton, apples, tobacco, soybeans and tea.
It can be used for the prevention of many kinds of pests or pest mites of vegetables, fruit and cotton.
|Production method||Producing strain: Streptomyces avermitills which is a new species of Streptomyces; it belongs to genus of Streptomyces griseus (the production strain of melbeycin similar to it is Streptomyces hygroscopicus). |
Morphology: aerial mycelium branches with spores usually appearing in oatmeal agar, glycerol, aspartame, salt, starch and egg white agar. With the observation through electron microscope, its spore hypha is initially close spiral, and later gradually released. The number of spores on spore chains is generally over 15. The spore exhibits round to oval-shape and smooth surface.
The breeding of strain is very important. Different species of Avermectin can cause different content of various kinds of components in fermentation broth. The application of newly high-yield strains not only improve the overall unit of Avermectin but also increase the proportion of component B1 significantly.
The preservation of strain: Avermectin producing strains are first growing in YMS slants (4.0 g of yeast extract, 10.0 g of malt extract, 4.0 g of soluble starch, 20.0 g of agar, water 1000mL, pH = 7.4). Further place spores in 20% aqueous solution of glycerol and stored at -30 ℃.
Seeds preparation: generally you can adopt two media, the content in 1000mL water is as below.
A: Cerelose 1.0g, soluble starch 10.0g, beef extract 3.0g, Ardamine PH 5.0g, N-Z-Amine E 5.0g, MgSO4 • 7H2O 0.05g, KH2PO4 0.182g, Na2HPO4 0.190g, CaCO3 0.5g, pH = 7.0.
B: Lactose 20.0g, distillers' Solubles 15g, Ardamine PH 5.0g, pH = 7.0. Inoculate glycerol spores stock into the above seed medium and have it grow for 1 ~ 2 d at 28℃ before further inoculation into the fermentation medium with the inoculation amount usually being 3% to 5%.
Biosynthesis: use the following fermentation medium for biosynthesis purpose.
A: Amidax 40g, distillers' Solubles 7g, Ardamine PH 5g, CoCl2 • 6H2O 0.05g, water 1000mL, pH = 7.3.
B: Cerelose 45g, Prepionlzed milk nutrient 24g, Ardamine PH 2.5g, polyethylene glycol P-2000 2.5mL, water 1000mL, pH = 7.0.
Studies have shown that the amount of produced Avermectin is related to the following factors: 1. species. Strain breeding can not only increase fermentation unit produced by microorganisms but also can change the ratio of each component, thereby improving the content of the required components. It has been reported that addition of methyltransferase inhibitor such as Slnefungin and S-adenosyl methione etc. can also change the ratio of component A and B in the product; For strain morphology, we should choose strain species with strong hypha for fermentation (the medium used for PAMcCann contains 0.4% of dextrin, 1% of meat extract, 0.4% of yeast, and 2% of agar, pH = 7.0). 2. C / N ratio. This has a large impact on yield and the component. 3. Defoamers. Polyethylene glycol is the preferred defoamers which not only improves the fermentation unit but also can inhibit the generation of yellow orange wax during the fermentation process; 4. Stirring; this has a large impact on the fermentation. Due to the sensitivity of the mycelium to the impeller shear, so the use of hydrofoil wheeled stirring device can improve oxygen supply and improve production. 5. Inorganic salts. No beneficial effect has been observed on the fermentation of various other inorganic salts.
|Chemical Properties||Off-White to Yellow Crystalline Solid|
|Usage||Mixture of avermectins, containing at least 80% of avermectin B1a (C48H72O14) and not more than 20% of avermectin B1b (C47H70O14). Used as acaricide, insecticide|
|Usage||ectoparasiticide, CNS stimuant, mutagen|
|Acute toxicity||oral-rat LD50: 10 mg / kg; Oral - Mouse LD50: 13.6 mg / kg
|Storage characteristics||Treasury: ventilation, low-temperature and dry; store and transport it separately from food raw materials;
|Extinguishing agent||Dry powder, foam, sand.|
|General Description||Odorless off-white to yellow crystals from methanol. Does not hydrolyze in water at pH 3, 5, 7. Used as an acaricide and insecticide.|
|Reactivity Profile||A lactone.|
|Abamectin Preparation Products And Raw materials|