From Big Medical Encyclopedia

PYRETHROIDS — synthetic analogs of natural pyrethrins — the substances having the expressed insecticidal properties.

Natural pyrethrins contain in pyrethrum (see). Items are applied to fight against arthropods — carriers of causative agents of diseases, and also to extermination of insects — wreckers in agriculture.

Items — oily or crystal substances, are esters chrysanthemumic to - you (or its analogs) with alcohols of a certain type. More than 5 thousand pyrethroids are known. From P. in disinsection use allethrin, bioal-letrin, superbioallethrin, neopi-namin, resmetrin, bioresmetrin, sou-mitrin, permethrin, tsipermetrin and nek-ry others. Nek-rye P. (allethrin, bioallethrin, superbioallethrin) are unstable on light and in the presence of oxygen. Other P., especially permethrin and tsipermetrin, are stabler, steady against action of ultraviolet rays. In the environment of P. decay on non-toxic components.

Items — insecticides of contact action, are highly effective concerning arthropod many types and a malotoksichna for hematothermal. Under the influence of P. insects at first have a hypermotility, then there comes bystry and deep paralysis. Resistance of arthropods to P. is observed seldom.

From P. prepare powdery drugs, solutions (in organic solvents), the emulsified concentrates. Apply to extermination of flying P.'s insects in the form of the aerosol received from liquid or powdery drugs by various methods (mechanical, thermal). It is reasonable to apply compoundings into which structure, except P., insecticides with long residual action, napr, metatiyen, baygon, etc. enter to fight against not flying insects.

In many cases of P. apply in mix with Synergists (piperonyl-butoxide, bukariolaty, etc.) — the substances which do not have insecticidal properties, but strengthening toxic action of insecticides, including the Item.

Though pyrethroids of a malotoksichna for hematothermal, at use of the drugs P. containing various fillers or solvents it is recommended to protect a respiratory organs (use of respirators, a gauze bandage) during the processing of rooms, to delete foodstuff from the room, to air rooms after their processing.

See also Pesticides .

Bibliography: Korotkova O. A. and Promonenkov V. K. Searches of new pesticides among pyrethroids, M., 1978, bibliogr.

Yu. P. Volkov.