ABSTRACT
In nature, plants protect themselves against insect attack mainly by mechanical and chemical defences. Mechanical defence includes formation of thick cuticle, which prevents insects from picking for food or laying eggs. Chemical defences are highly developed in plants in the form of secondary metabolites. These secondary metabolites are the product of primary metabolites and referred to as insecticides. Insecticidal properties of over 2000 plant species and their traditional uses were established from the ancient time. Yet, as of today, insecticidal compounds have been isolated only from ca. 70 plants and their chemical structures were elucidated. The chemical natures of these insecticidal compounds are varying widely from simple alkaloids (nicotine, anabasin), complex esters (pyrethrins), heterocyclic aromatic compounds (rotenoids), steroids (phytoecdysones) etc.
