A cinderella metal

Abstract

Local plants are used throughout the world for making insecticidal preparations. Compounds containing insecticidal properties occur in many plant parts, for example—pyrethrins in the flower heads of pyrethrum, nicotine in the leaves of tobacco, rotenoids in the roots of denis, and ryanodine in the stem of ryania. This chapter discusses these plant insecticides. The most important natural plant insecticides are the pyrethrins. These compounds are of great interest because of their lethal activity against insects, low toxicity to mammals, and low persistence after use. They paralyze flying insects very rapidly. Pyrethrum is a small perennial herb, with deeply lobed leaves of variable shape and length. Pyrethrins are a mixture of six structurally related insecticidal esters formed by a combination of two acids and three alcohols. Phytoecdysones are found in plants and are analogs of ecdysteroids, a group of insect hormones that initiates the cycles of ecdysis in insect development. They can disrupt the growth cycles of insects and this can result in the formation of abnormal adults.