Insecticides of Natural Origin PDF

PREFACE

Pest management is an important and vital component in modem production of food and fibre, which are needed in increasing quantities to meet the demands of the world's burgeoning population. A crucial component of this management is the use of chemicals to control insect pests, which not only attack plants and plant products at various stages of production, but also destroy structures and transmit human and livestock diseases. There are approximately one million insect species in the world, amounting to some 70% of all species in the animal kingdom. Of these, around 10,000 have been recognized as harmful. It has been estimated that 14% of crop losses worldwide are caused by insect pests. Manhours lost as a result of insect-borne diseases, such as malaria, filaria, trypanosomiasis, etc., are enormous. The magnitude of this aspect may be gauged from the estimate that there are as many as 200 million clinical cases of malaria world-wide annually, resulting in a million deaths.

Thus control of harmful insects is a must for mankind. Though various new strategies for plant protection and insect control are emerging, insecticides continue to play a dominant role, and it appears unlikely that insecticides will ever be bypassed. However, there is enormous scope for discovery of safer (mammalian toxicity), more potent, and environmentally non-polluting insecticides. This becomes all the more significant in view of the ability of insects to develop resistance on sustained use of the same or similar (mechanistically) insecticides. This problem has been further compounded by cross resistance and multiple resistance. Of the various strategies used for developing new biologically active molecules for specific applications, probing nature's bounty of so-called secondary metabolites has proved quite effective in the past, and promises to remain so in the foreseeable future. An excellent example in the specific area of insecticides, is the development of pyrethroids, the lead for which came from secondary metabolites of the flowers of Chrysanthemum cinerariaefolium. Thus, it appeared desirable to collect known information on the insecticidal properties of constituents of higher plants, microorganisms, animals, and marine flora and fauna in order to assist researchers in selecting leads for further development. The present book is the result of such an endeavour.

The book has been divided into two sections. Section I gives a brief general introduction to the subject matter to put the topic in proper perspective, while Section 2, the so called Monograph Section, presents relevant information on compounds and extracts in a form which is directly accessible. Insect growth regulators (e.g., juvenoids), anti-feedants, repellents and attractants, though useful in insect control, are not insecticides, and have not been included. Literature has been screened until the end of 1992, although every efforts has been made to provide the latest structural information on pure compounds.

Authors: Sukh Dev, Opender Koul