Login for faster access to the best deals. Click here if you don't have an account.

NATURAL FERTILIZER- A FEW THINGS YOU SHOULD KNOW Private

1 year ago Multimedia Warangal   70 views

-- ₹

  • img
Location: Warangal
Price: -- ₹

Pyrethrum, also known as Dalmatian (or, inaccurately, Persian) insect powder, represents the dried flowers of the daisylike herbaceous perennial Tanacetum (Chrysanthemum) cinerariaefolium (Compositae) growing naturally along the east coast of the Adriatic Sea. It is the source of the economically most important botanical insecticides. Pyrethrum is one of the oldest natural insecticides in use in the world today, and it has one of the best safety records of all insecticides. It is a mixture of several esters, called pyrethrins, which are extracted from flowers belonging to the genus Chrysanthemum. Natural pyrethrins are unstable to light and are therefore unsuitable for residual application, particularly in agriculture. This led to the development of several classes of related synthetic compounds which have a higher stability to light and a high insecticidal activity. They are known as pyrethroids. In general, pyrethroids can be toxicologically divided into two classes on the basis of signs of toxicity: those causing mainly tremor and prostration (T syndrome) and those causing choreoathetosis and salivation (CS syndrome). For both groups, the main biological activity is mediated through the effect on sodium channels along the axon membrane of the nerves, in both insects and mammals. The effect on the sodium-exchange disturbance is fully reversible, the duration of which is different for the two classes of pyrethroids: compounds belonging to the group causing the T syndrome produce a considerably shorter effect on the sodium ‘gate’ openings than those belonging to the CS group. Being highly lipophilic, pyrethroids readily pass through cell membranes and are absorbed into the body by all routes following exposure. However, the ratio of the toxic dose by the oral route to that of intravenous injection is very high; this is because of rapid detoxification, mainly by cleaving of the ester bond by esterases. Present-day evidence indicates that doses of a pyrethroid likely to be encountered both in the workplace and through food consumption would not lead to any serious untoward effects, although reversible transient effects on the skin may be recorded and may be used as a warning response of inadvertent exposure.