Insecticides call the chemicals killing insects, their larvae and eggs. Main application of insecticides — protection of crops against insects wreckers. They are used for fight against household insects, carriers of diseases and by ektoparazitam of animals and also for protection of food products.
Instruction
1. Insecticides are issued in solutions, concentrates of emulsions, powders and aerosol medicines. Besides active ingredient, they contain thinner and other auxiliary additives. The efficiency of medicine in many respects depends on its structure and form.
2. The range of insecticides constantly is replenished that is connected with emergence among insects of races, resistant (resistant) to the existing medicines. About 250 active ingredients are known, at the same time various firms produce tens of thousands of medicines under the signature names.
3. Insecticides separate into groups, depending on their way of penetration into organism of insect. Contact medicines are inhausted through external covers at contact, fumigants get through respiratory organs, intestinal insecticides get to organism of insect when swallowing. System insecticides are capable to move on the vascular system of plant, doing it toxic for insect.
4. Many insecticides are toxic not only for insects, but also for animals therefore they for practical use try to select medicines which quickly collapse in organism of warm-blooded or are non-toxic for animals and the person. At the same time for insects they have to have high toxicity, and collapse slowly. Some of such substances are called pro-insecticides, they turn into insecticides only in organism of insects.
5. Among insecticides of plant origin the greatest application is found by piretina which contain in sort camomile flowers pyrethrum and also their more stable and effective synthetic analogs — pyrethroids. The natural insecticide rotenon is allocated from extract of roots of derris.
6. Some insecticides are waste products of bacteria. The high insecticidal activity is characteristic of group of macrocyclic antibiotics — avermektin which are allocated by radiant mushroom of Streptomyces avermitilis. These connections are effective at fight with endo- and ekzoparazitam of animals.
7. One of the most important representatives of organochlorine insecticides is DDT, possessing broad spectrum of activity against various wreckers of crops. Now its application is forbidden in many countries because of toxicity and ability to collect in fatty tissues of the person and animals and also because of high resistance to decomposition in the environment.