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Acute toxicity of the thiametoxam in preparats actara for white mice
Neonicotinoids are the insecticides of systemic and contact-intestinal action with translaminar activity. In agriculture it is applied against sucking, leaf-eating insects and soil pests, treatments for vegetative crops and as seed disinfectants. For Neonicotinoids the action on the nervous system of pests is characteristic.
Neonicotinoids are a class of neuro-active insecticides chemically similar to nicotine. The development of this class of insecticides began with work in the 1980s by Shell and the 1990s by Bayer. The neonicotinoids were developed in large part because they show reduced toxicity compared to previously used organophosphate and carbamate insecticides. Most neonicotinoids show much lower toxicity in mammals than insects, but some breakdown products are toxic. Neonicotinoids are the first new class of insecticides introduced in the last 50 years, and the neonicotinoid imidacloprid is currently the most widely used insecticide in the world. The neonicotinoids include acetamiprid, clothianidin, imidacloprid, sulfoxaflor, nitenpyram, nithiazine, thiacloprid and thiamethoxam.
А representative neonicotinoid, is effective against sucking insects, some chewing insects, soil insects, and is also used to control fleas on domestic animals.
Neonicotinoids is possibly the most widely used insecticide, both within the mode of action group and in the worldwide market. It is now applied against soil, seed, timber and animal pests as well as foliar treatments for crops including: cereals, cotton, grain, legumes, potatoes, pome fruits, rice, turf and vegetables. It is systemic with particular efficacy against sucking insects and has a long residual activity. Imidacloprid can be added to the water used to irrigate plants.
The application rates for neonicotinoid insecticides are much lower than older, traditionally used insecticides.
Most neonicotinoids, such as imidacloprid, show low affinity for mammalian nicotinic acetylcholine receptors (nAChRs) while exhibiting high affinity for insect nAChRs. Mammals and insects have structural differences in nAChRs that affect how strongly particular molecules bind, both in the composition of the receptor subunits and the structures of the receptors themselves. The low mammalian toxicity of imidacloprid can be explained in large part by its lack of a charged nitrogen atom at physiological pH. The uncharged molecule can penetrate the insect blood-brain barrier, while the human blood-brain barrier filters it.
Experiments were conducted at the Department of Pharmacology and Toxicology, National University of Life and Environmental Sciences of Ukraine and the vivarium of the Veterinary Medicine Faculty of NULES of Ukraine.
The parameters of the acute toxicity of insecticides Actara, which has Thiamethoxam as a main active ingredient in its composition, that belongs to a relatively new class of pesticides – Neonicotinoids, are determined.
Thiamethoxam is an insecticide in the class of Neonicotinoids. It has a broad spectrum of activity against many types of insects.
Thiamethoxam was developed by Syngenta.
Thiamethoxam is a systemic insecticide that is absorbed quickly by plants and transported to all parts of the plant, where it acts as a deterrent to insect feeding. It is active in the stomach of the insects, and also through direct contact. The compound interferes with information transfer between nerve cells, making the insects become paralyzed.
Thiamethoxam is a moderately toxic substance. In normal use, there are no unacceptable risks involved. The substance is toxic to bees and harmful to aquatic and soil organisms, although the level of toxicity to bees is not yet clear.
The experiments were carried out on white mice. Laboratory animals were housed in vivarium conditions. It was established that the toxic effects of Actara during intragastric administration to white mice is developed by action of the drug in doses of 3500 mg/kg and above. Absolute lethal dose DL100=4800 mg/kg. Calculations were made to determine the median lethal dose DL50 and intermediate doses DL84 and DL16. To estimate the median lethal dose the G. Kerber method was used. Standard error of measurement (m) of the median lethal dose was calculated by the method of K. Miller and M. Teynter. It was established that under certain median lethal dose for laboratory mice (DL50=3631,24±96,12 mg/kg) according to the classification of chemicals according to the degree of hazard it belongs to the third class. According to the classification of substances for toxicity it refers to low-toxic.
Key words: insecticides, neonicotinoides, thiametoxam, actara, acute toxicity, lethal dose, average lethal dose, laboratory mice, degree of danger.
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