Proceedings of The Biochemical Society

Abstract

The discovery and production of selective herbicides in the past decade has been phenomenal. Even so many weed-control problems still remain unsolved and there is a continuing demand for new herbicides active against particular weeds and characterized by improved selectivity. A historical review of our most effective pesticides reveals that the discovery of biological activity in synthetic chemicals has, in most instances, resulted from empiricism or chance (Sexton, 1963; Moorefield, 1965). In the future, however, we shall rely more and more on an improved knowledge of the physiology and biochemistry of herbicide interactions to modify and extend the processes of empirical screening. To evolve a successful herbicide requires firstly the discovery, usually by chance, of a 'lead', i.e. a novel chemical structure possessing some degree of biological activity, and secondly a development programme wherein the relationships between chemical structure, biological activity and species selectivity are examined in an empirical screening programme (whole plants). In the progression of