Experts in herbicide research and development - chemists and plant physiologists -, have written 15 chapters that review all aspects pertinent to peroxidizing herbicides, compounds of topical interest since extremely low use rates ensure high environmental safety. Topics covered include structure-activity relationships, relevant patent literature, preparative methods, modes of action, greenhouse screening, laboratory assays, plant pigment biochemistry, and enzymology of the decisive target enzyme of this class of herbicides. This comprehensive review will be welcomed as a unique and timely compilation of the current status of peroxidizing herbicide research and development. It will be of interest to professional chemists and biologists in agrochemical companies, universities and agricultural colleges.

Since the middle of the Sixties, new types of formulation for biologically active com pounds have been developed, which have been introduced into the literature under the term Controlled Release Formulations (CRF). Stimulated by results from former and successful pharmaceutical research, which was engaged in the production of prepa rations with protracted effects (introduction onto the market in the year 1952 of D amphetamine in the form of pellets, coated to varying degrees with fats and waxes) 1), experiments were carried out to transfer the prolongation of effectiveness to pesticidal substances also, by means of a depot formulation. Initial work was concerned with the production of protective coatings for sonar systems in marine ecosystems. By means of antifouling paints or rubber coatings containing tri-n-butyl-tin oxide (TBTO), the growth of marine organisms on sonar domes, buoys and hulls in the water could be effectively prevented 2. 3). Controlled release formUlations of pesticides are defined as depot systems which continuously release their toxic constituents into the environment over a specified period of time (usually months to years) 4). According to this definition, such formu lations can be successfully employed where a chronic exposure to biologically active compounds is required over a longer period. The following hypothetical example is intended to illustrate this 5). In Fig. 1, the duration of activity of a non-persistent pesticide with a loss rate under environmental conditions of t1/2 = 15 days, is graphically illustrated."

Chemical pest control is in use in practically every country in the world since agrochemicals play a decisive role in ensuring food supply and protection against damage by pests, insects and pathogenic fungi. Particularly in the half century since World War II, food production has risen dramatically in most parts of the world. In the last 20 years, the yield of major crops has roughly doubled in Western agriculture and there is still the potential for further achievements, particularly in the developing countries. The world's cereal and rice production, now more than 2 billion tons/year, has to increase by 2. 4% annually to cope with the rising food demand caused mainly by the growing population and improvement of living standards in most of the developing countries. Such a demand for food has to be achieved by higher yields from the restricted arable land already in use. Global farm land resources are about 1. 4 billion ha, of which 1. 2 billion ha is cultivated with major crops. Experts agree that a future substantial addition of new produc tive areas is unlikely. Those with a high yield potential are already in use; new fields with a lower output may possibly be obtained by cultivation of arid or cold areas. More recently, new areas of large-scale farmland have been devel oped in tropical regions of Latin America, primarily in Argentina and Brazil, at the cost of the destruction of tropical rain forest.

This book presents the progress made in the study of the mode of action of phytotoxic compounds that have been developed as herbicides in the recent past. The 13 chapters are written by experts in herbicide research and development, chemists, biochemists, and plant physiologists. The biochemistry of the target enzymes is described together with model assays, molecular genetics and special reference to transgenic herbicide-resistant crops. Additional chapters deal with new synthetic chemical pathways, chirality effects found in certain herbicide classes, and transcuticular pesticide penetration.