Chemistry of Plant Protection – serie

Over the past 30 years one alarming trend is the emergence of plant species resistant to agrochemicals (e. g. insecticides, herbicides, fungicides). Considering the fact that these pesticides are crucial to human health and to food, feed and fiber production, impressive research was carried out during the last decade to understand the mechanisms of resistance development. This volume reviews the latest results and examines the implications of these findings for delaying or avoiding resistance in plants to agrochemicals.

Over the past 30 years one alarming trend is the emergence of plant species resistant to agrochemicals (e.g. insecticides, herbicides, fungicides). Considering the fact that these pesticides are crucial to human health and to food, feed and fiber production, impressive research was carried out during the last decade to understand the mechanisms of resistance development. This volume reviews the latest results and examines the implications of these findings for delaying or avoiding resistance in plants to agrochemicals.

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.

Chemistry of Plant Protection, Volume 7, provides critical review articles on new aspects of herbicide resis- tance, serving the needs of research scientists, pesticide manufacturers, government regulators, agricultural practitioners.

Living organisms are separated from the outside world by their membranes, which perform important roles for maintaining their lives. Sterols are indispensable com- ponents in eukaryotic organisms for stabilizing membranes composed of phospho- lipid bilayers. Most prokaryotic organisms, on the other hand, do not contain sterols in their membranes, although recent studies indicated that the bacterium Methylo- coccus capsulatus produces sterols 1) and many strains of Mycoplasma, bacteria without cell walls, require sterols as an essential growth factor 2). Some bacterial species synthesize hopanoids which are hypothesized to function like st~rols in eu- karyotic organisms 3). Significance of ergosterol in fungi has been recognized from the fact that the yeast Saccharomyces cerevisiae requires ergosterol for growth, when cultured in a strictly anaerobic condition "'. l:.lectron microscopic studies showed that membrane structures disappeared in the yeast grown anaerobically without a supplement of ergosterol 5.6), indicating the necessity of ergosterol for membrane biogenesis.Further confirmation of the significant role of ergosterol in the membranes was derived from the studies on polyene antibiotics. In the presence of polyenes such as nystatin, filipin and amphotericin B, fungal cells lose selective permeability of the membranes, since polyenes interact with ergosterol, such that the structure of the fungal membranes is disrupted 7).

The series "Chemistry of Plant Protection" continues the handbook "Chemie der Pflanzenschutz- und Schadlingsbekampfungsmittel", edited by R. Wegler. This volume covers contributions in the fields of pesticide degradation, desiccation and defoliation, and the acetyl choline receptor in insects.

The series "Chemistry of Plant Protection" continues the handbook "Chemie der Pflanzenschutz- und Schadlingsbekampfungsmittel", edited by R. Wegler. This volume covers contributions in the fields of pyrethroid residues and immunoassays.

The idea of Volums 4 and 5 of this series is a combination of a very condensed but broad review, handbook and textbook on most of the theoretical and practical aspects of pyrethroids of interest to chemists, biologists, pharmacologists, toxicologists and other people involved in insecticidal research, development, ecotoxicolo­ gy, application, patenting and commercialization of pyrethroids, as seen from a point of view of an industrial chemist once actively in volved in pyrethroid research. In order to provide a mode1 data base for testing quantitative structure activity relationships, the unique wealth of the numerous and diverse biological data dispersed in the literature is listed in about 110 tables, put in relation to each other and other standard compounds, together with many structural formulas of the com­ pounds involved. A number of data are published for the first time. Some of the more important reeent QSAR-studies are briefly acknowledged. Conformational aspects of bioactive pyrethroids are discussed (from synthesis, QSAR, X-ray); some of the X-ray derived conformations are published for the first time. The molecular basis of pyrethroid biological action is taken into consideration as intensively as possible. Stereochemical aspects are considered wherever they are involved in synthesis, biological activity, mode of action, metabolism (Vol. 4), and particularly in the complex problems in the production and relation of iso­ merically enriched trade products (Vol. 5). Since pyrethroid research is now, in manyaspeets, a finished chapter of applied research, a historieal treatment of the course of inventions is given (inventions, patent priorities).

Chemistry of Plant Protection continues the handbook "Chemie der Pflanzenschutz- und Schadlingsbekampfungsmittel", edited by R. Wegler. Volumes 4 and 5 of the series provide the first complete and in depth overview of synthetic pyrethroid insecticides . Volume 5 presents a detailed survey of the numerous synthetic methods (270 reaction schemes) and of stereochemical aspects of trade products, and a compilation of almost every patent on pyrethroids (2700 references evaluated).

Pesticides in ground, surface and drinking water are a hot topic under continuing discussion. This complete and authoritative volume draws together information on all key issues on the fate and behaviour of pesticides in water systems. The scope of the practice-oriented contributions and the eminence of contributing authors make it an important source for researchers and practitioners in the plant protection and crop science field.

Chemicals inhibiting the biosynthesis of branched-chain amino acids form a new and promising class of herbicides. This volume discusses in an authoritative way recent developments in this field and covers important aspects of these potent herbicides (synthesis, structure-activity, mode of action, selectivity, weed resistance, metabolism).

Public concern is being increasingly directed to pesticides and their residues in ground and surface waters. Water - one of the necessities of life - has to be kept clean for man and the environment.