Insects poisonous substance production

Pyrethrin is a natural insecticide obtained from the powdered flower heads of several species of Chrysanthemum. The active substances in pyrethrum, principally pyrethrins I and II, are contact poisons for insects and cold-blooded vertebrates. Although powders made from Chrysanthemum extracts have found widespread use, the active substances in them are destroyed rapidly in the environment. In an effort to develop synthetic compounds as effective as the natural insecticides but with greater biostability, chemists prepared a series of esters related in structure. Among the synthetic pyrethrenoids now in common use in household and agricultural products are permethrin and bifenthrin. 

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