Simon J. Yu
CRC Press, Boca Raton, FL
2008; 276 pp.
ISBN: 1-4200-5975-0 (hardcover)

Dr. Yu is correct in his introductory statement that there is a scarcity of books on the subject of insecticide toxicology and biochemistry. This has been especially true over the past 25 years, when some of the most important insecticides currently being used were developed and introduced. Dr. Yu’s book extends the tradition established by classic previous titles and the lecture notes of a noted authority. The Toxicology and Biochemistry of Insecticides broadens the discussion beyond organophosphates to include neonicotinoids, phenylpyrazoles, formamidines, and others. Additionally, many emerging ideas in the fields of biochemistry and molecular biology are integrated into the discussion.

The most valuable contributions of this book are the inclusion of the newer chemistries and its discussions of pesticide formulation and pesticide metabolism (including species differences, the effects of insect age, sex, and enzyme induction), as well as a very thorough section on insecticide resistance. Entire books can and have been written on each of these subjects, and the chapters devoted to them in the current title provide overviews that are sufficiently referenced to allow the reader to pursue the topics further. 

The section likely to be of most use to students is the chapter on the classification of insecticides. The chapter is well illustrated with chemical structures. Basic mammalian toxicity data are presented, and the range of use of the compounds is provided, but only briefly. The classic chlorinated hydrocarbon insecticides (DDT, cyclodienes, etc.) are included, although their discussion is greatly shortened relative to older titles on the subject. This is appropriate, as the older compounds, despite their historical significance, are of diminishing importance to current students of insecticide chemistry. The section includes the newer compounds, the classification of which is difficult due to their diversity. Indeed, nearly all of the newer classes contain only one or two compounds. Microbial insecticides are discussed, with Bt not surprisingly garnering the most attention.

The following chapters are arranged in a logical progression of insecticide action, beginning with how the insect encounters the insecticide (via ingestion, contact, or inhalation), followed by mode of action and metabolism. The mode of action chapter is arranged according to general mode of action (sodium channels, calcium channels, acetylcholinesterase, etc.), with each section further divided into specific modes of action, if applicable. Recent biochemical studies are cited and the compounds’ actions at the receptors are described in detail. The metabolism of insecticides is approached from a biochemical (rather than an active ingredient) standpoint, describing the various phase I and phase II reactions in turn. The metabolism of individual insecticide classes is discussed after the reader has been made familiar with the general principals of xenobiotic metabolism.

One long-ignored (or at least poorly studied) problem is that many factors can affect insecticide efficacy. It’s long been recognized that species—and different populations within a species—can differ in their susceptibility to insecticides. This is most easily attributed to differences in detoxification enzymes, which Dr. Yu describes well in this book. Such factors as the age and sex of the insect, differential expression of enzymes, the induction of enzymes prior to exposure to the same or other insecticides, and the inclusion of synergists all contribute to the observed differences in susceptibility.

Two of the most important negative consequences of insecticide use—insecticide resistance and adverse effects on the environment—comprise the final two chapters. The genetic basis of biochemical resistance is discussed, followed by a discussion of the various mechanisms of resistance (both behavioral and physiological) and resistance management. The multifaceted subject of pesticides in the environment is addressed in sufficient detail to outline the major issues. Once in the environment, an active ingredient is exposed to a number of factors that can lengthen or shorten the window of activity. Soil moisture, sunlight, soil pH, and other forces can interfere with a molecule’s activity, in most cases shortening its longevity. This is advantageous for compounds posing a threat to the environment, but environmental degradation of a compound is detrimental when persistence is desired. Each of these parameters is discussed briefly, followed by a discussion of non-target effects on wildlife, such as bioaccumulation, endocrine disruption, and eggshell thinning in birds.

More details regarding the use of the insecticides, as well as more citations regarding facts that are accepted by experts but with which students might not be familiar, would improve future editions of this book. However, many subjects are presented in a manner accessible to students who might not yet be familiar with the material, making the book appropriate for classroom instruction. Noted authorities are referenced in the text, allowing readers access to the primary literature. The material is presented in an informative, familiar format.

Christopher Peterson
USDA, Forest Service
201 Lincoln Green
Starkville, MS, 39759
E-mail: cjpeterson@fs.fed.us

American Entomologist
Vol. 57, No.2, Summer 2011