NATURAL-PRODUCTS IN PLANT-PROTECTION

Natural products can be used to control pests and diseases in crops. T hese products include anorganic compounds, but also a variety of plant extracts. In the beginning of this century active microbial extracts were discovered as well. Synthetic crop protection chemicals were deve loped from about 1940 onwards and sustained progress in modem agricult ure. The first generation chemicals have aspecific modes of toxic acti on and are in many instances deleterious to the environment. The secon d generation chemicals have specific modes of action and meet modem en vironmental requirements. A disadvantage of these chemicals is the pot ency of target organisms to acquire resistance. This condition urged a grochemical industry to develop chemicals with new modes of action. Su ch chemicals can be developed by using natural bioactive products as l eads in synthesis programmes. This paper decribes the progress that wa s made in the development of natural bioactive compounds in pest and d isease control.