March 1997 Vol.18 No.1

New Books

Microbial Pesticides

Less than 8% of the active ingredients commercially available as pesticides are derived from natural products. However, the pressure is on for the crop protection industry to find new classes of chemistry that will yield tomorrow's pesticides, and the example set by the pharmaceutical industry suggests that natural products are where to look. This book* examines the compounds that have been found to show useful biological effects and describes their modes of action and the attempts to modify their chemical structure to render them more suitable for application as agrochemicals. Naturally occurring defence systems and biological control techniques are discussed.

Chapter 1 re-examines the world of microorganisms and lists biologically active compounds. Chapter 2 des-cribes the compounds discovered and used in agriculture from the fer-mentation of microorganisms and discusses the possibility of transferr-ing their traits to crop plants, while chapter 3 takes the theme further with the combination of useful biological activity from wood invading fungi and the application of targeted chemical synthesis to stabilize it to produce useful fungicides. In chapter 4, the potential that exists in rhizosphere bacteria to produce new herbicides is demonstrated, while chapter 5 examines, in depth, the chemical diversity and biological activity of algal derived compounds.

Chapter 6 describes a wide range of compounds from higher plants which show potential for exploitation in crop protection and chapter 7 is a descrip-tion of the commercialization of the synthetic pyrethroids. Chapter 8 examines the role of natural plant defence mechanisms, warning that natural compounds might not be any safer than synthetic chemicals.

Chapter 9 describes the diversity of chemistry and biochemical modes of action that can be found in toxins from the animal kingdom, and how these have been examined as potential new insecticides. Molecular biological techniques allow the exploitation of compounds once thought too comp-lex to use.

Bacillus thuringiensis endotoxins currently represent over 90% of the use of biological compounds globally, and chapter 10 describes the structure and biological efficacy of these toxins, outlining in simple terms the classification of different toxin structures and the potential for their use. Chapter 11 describes the biology of baculoviruses and the commercial products that are available today. Advances in the use of genetic manipulation to enhance the potential for their use in agriculture are explored. The use of antagonistic microorganisms to control plant pathogens is dealt with in chapter 12, while chapter 13 covers plant pathogens developed as microbial herbicides.

Finally, the registration of new natural pesticides, particularly moves towards reduced registration require-ments for naturally derived chemicals and biological control systems, is covered in chapter 14. Overall, this book examines all aspects of the natural world as a source of crop protection agents. There is a huge variety of options available, but the crop protection industry is only just beginning to investigate these resources.

*Copping, L.C. (ed) (1996) Crop protection agents from nature: natural products and analogues. Cambridge, UK; The Royal Society of Chemistry, 501 pp.

ISBN 0 85404 414 0, price £129/$219.

Invader Ecology

Invasive species keep biological control specialists in employment, because many of them become serious pests, so another book on the subject is worth seeing. But not all invaders are pests, and not all invasions are successful. One theme of this book* is that the reasons for this are not well understood and that prediction is difficult. However, ecology is advanc-ing fast, and the variable patterns of invasions are being better described and interpreted, leading to hopes of a better quantitative understanding.

This book goes beyond case histories to give an overview of the invasion process. To this end, the author has developed a conceptual framework of eleven points arranged in four sets, which is explained in chapter 1. Points 0-4 cover arrival and establishment; point 5 spread; points 6-8 equilibrium and effects; and points 9 and 10 implications. The remaining chapters of the book then fit into this frame-work as follows: chapter 2, the origins and the success and failure of invasions (points 0-2); chapter 3, which communities are invaded by which type of species? (3 and 4); chapter 4, the process of spread (5); chapter 5, ecological consequences of invasions (6 and 7); chapter 6, genetic and evolutionary effects (8); and chapter 7, implications and com-munities (9 and 10).

Although somewhat critical of past biological control attempts using less specific natural enemies, this book has some interesting things to say to anyone who has to deal with the consequences of invasive species.

Williamson, M. (1996) Biological invasions. London; Chapman & Hall, 244 pp.

ISBN 0 412 31170 4, price £55 (hbk); ISBN 0 412 59190 1, price £24.99 (pbk).

Citrus IPM

The adverse effects of the overuse of chemical pesticides on citrus in northern Mediterranean countries has led to a growing interest in biological control methods and other alter-natives in the region. Mediterranean citrus is one of the most suitable candidates for integrated pest management and this book* is a major information source from one of the leading research centres in the area.

The main insect pests of citrus in the Mediterranean region are described and current pest control practices are summarized. Progress to date in biological control and IPM is rev-iewed and possible strategies against the main citrus insect pests are given. With 149 colour photographs, the book is a reference manual for entomologists, crop protection workers, citrus growers and anyone else involved in the implementation of IPM in Mediterranean citrus.

*Katsoyannos, P. (1996) Integrated insect pest management for citrus in northern Mediterranean countries. Athens; Benaki Phytopathological Institute, 110 pp.

ISBN 960 00 1002 1, price $40.