Journal of Chemical Ecology. Vol. 22, No. 10, 1996
BOOK REVIEW
Analyses in Insect Ecology and Management. Larry Pedigo and Michael Zeiss. Iowa State University Press, Ames, Iowa, 1996. Hardback, ISBN 0-8138-28619, 168 pp. $64.95.
There is an essential suite of quantitative tools with which any applied entomologist working in pest management should have a working knowledge. This book attempts to provide an overview with working examples of many of these tools. The authors suggest that the book is intended as a primer that can be used in an autotutorial mode by students or professionals or as a laboratory manual for graduate-level courses in insect ecology or pest management. The book is organized into eight short chapters and is accompanied by a diskette of DOS computer programs (ENSTAT) that complement many of the lessons. Each chapter concludes with sample problems to exemplify the topic area covered, a series of questions, and a bibliography of selected papers. An answer key is available free of charge from the publisher. There is no index. The first chapter is a short introduction to using the statistical portion of ENSTAT along with several small data sets for practicing use of the software. The software can perform simple one and two-way analysis of variance, chisquare analysis and simple linear regression. The program would be useful to undergraduate or beginning graduate students with little experience in statistical analysis. Most professionals and upper level graduate students will find the program's capabilities limited and would be better off learning to use one of the more widely available statistical packages. Data entry is clumsy and the user cannot import existing data files nor export data sets for further analyses. Chapter 2 provides general coverage of the spatial distribution of insect populations. Some of the more common theoretical distributions such as the Poisson, negative binomial, and binomial distribution are explained and exemplified. Taylor's power law is covered briefly, but other common methods for empirically describing dispersion, for example the patchiness regression based on Lloyd's mean crowding index, are not mentioned. ENSTAT programs are provided to determine goodness of fit of field data to Poisson and negative binomial distributions. Chapters 3 and 4 address the development of sampling plans. The third chapter covers basic developnqent of sequential sampling plans for pest management application based on Wald's methods. These sequential plans basically allow a given pest population to be classified as either above or below a predetermined threshold level. They are typically quite efficient because few samt95t (X)98-0331/9(~/1000 19515(~,50/0 ic, 1996 Plcnunl Publishing Curp~lrdmln
1952
BOOKREVtEW
pies are needed to classify low or high population densities. Standard formulae are presented for calculating sequential stop lines based around the binomial, negative binomial, Poisson, and normal distributions. The software includes spreadsheet-based programs for calculating sequential stop lines for all but the normal distribution, and for estimating average sample number and error rates as a function of pest density. The chapter concludes with a reprint of a journal article exemplifying the development of a sequential sampling plan for a soybean pest. The fourth chapter discusses a specialized use of sequential sampling (timesequential) that attempts to classify whether a pest population is increasing or decreasing over time. Much of the concept and detail of the method is covered in a reprinted article by the first author. Again, ENSTAT contains a module for calculating stop lines. The degree-day model for predicting temperature-dependent development of insects is the subject of Chapter 5. Coverage here is elementary and the reader may want to consult references in the bibliography and software for greater detail. For example, there is no discussion of the sinewave method or of methods that use both a lower and upper development threshold. The software for calculating and accumulating degree-days contains a few bugs, but does permit the user to specify upper developmental thresholds and provides output using the rectangular, triangular, and sinewave method. The next two chapters cover the development and analysis of life tables. The text section is brief, with most of the detail provided in reprints of all, or parts of, several classic references by Harcourt, Ives, and Southwood. Good example data sets are provided for the practice construction and analysis of agespecific life tables. The authors also provide a fairly detailed set of step by step instructions for doing k-factor and key-factor analyses, techniques that attempt to identify causative factors in the population dynamics of a species over time and/or multiple sites. The text and bibliography discuss density-dependence, but do not address the continuing controversy over the validity of various techniques for measuring density-dependence. ENSTAT contains a module for life table construction. The final chapter covers the concept and develompent of economic injury levels (EIL), one of the most fundamental components of modem IPM. The book focuses on the ElL model of Pedigo and provides step by step instructions on how to calculate an ElL for a specific soybean pest. Again, the chapter concludes with a reprint of a journal article. The authors do not discuss other EIL models nor present methods for determining the economic threshold, the actual pest density at which suppressive action should be implemented. Analyses in Insect Ecology and Management is well written, and printed in fairly large type in single columns making it easy to read. Based on the subject matter covered, the level of detail, and the presentation format, the book would be most useful as a supplemental text for upper undergraduate or lower
BOOK REVIEW
1953
level graduate laboratory courses in insect pest management. Cost may be prohibitive, particularly if another book is required for the lecture portion of the course. Professionals wanting a good reference to some quantitative techniques would probably be a bit frustrated by the lack of depth, and those using the book in an autotutorial mode would definitely want to obtain the answer key. I am not a big fan of books that reprint original research articles that could be easily obtained elsewhere, but the approach does provide for self-contained lessons. The ENSTAT software has a few bugs, but is useful in furthering the educational value of the text. Most graduate students and professionals will quickly outgrow the programs. Steven E. Naranjo USDA-ARS, Western Cotton Research Lab 4135 East Broadway Road Phoenix, Arizona 85040
