the few on insects suggests that the cassava mealybug (Phenacoccus manihoti),
a serious pest accidentally introduced
into Africa about 1970, may now be
reaching an equilibrium, its populations
now held in check probably by native
predators: it causes less damage now in
the areas of Zaire where it was originally
found. A similar decrease has not been reported for the other important arthropod
pest, the cassave green mite (Mononychellus tanajoa), although a predacious
mite helps in Nigeria, and amount of leaf
hairiness is negatively correlated with
mite damage.
The topics range from the use of cassava root meal for the feeding of domestic
animals, through various combinations of
intercropping, to an improved peeling
machine. The wide range of studies, the
overall excellence of the work reported,
the willingness of economically strapped
governments to support the work, the
symposium, and its publication, and the
degree of cooperation manifest here-all
bode well for African science.
Carl W. Schaefer
Biological Sciences Group
University of Connecticut
Storrs, CT 06268
SEQUENTIAL
SAMPLING
FOR PEST
CONTROL
Guy Boivin and Charles Vincent. 1983. Contribution 1983-14E.Research Branch, Agriculture Canada,
Quebec. 29 pp. Free.
PROGRAMS.
This "book" is really not a book at all,
but rather a bulletin dealing with the
topic of sequential sampling. The paperbound publication addresses the Sequential Probability Ratio Test ofWald, and the
less widely used procedure of Iwao as
they are used for making decisions in in·
sect pest management. The stated purpose of this publication is to show advan·
tages and disadvantages of both methods.
The bulletin is divided into seven major
sections. An introduction presents background on the importance of sampling to
integrated pest management and its role
in decision making. Historical information
on sequential sampling is also given, and
its use as a tool for optimizing resources
is discussed. A useful summary of prerequisites is presented next that fanliliarizes
the reader with the inputs necessary for
developing sequential sampling programs.
In the third section, principles are discussed, with specific formulas and directions for the calculations presented. Following is a section that provides examples
of both the Wald and Iwao methods for a
64
mirid nymph, Lygocoris communis
(Knight). This part is particularly informative, for it allows the reader to compare both approaches using the same sampling technique for a single species. A
conclusions section is next that suggests
that the sequential sampling method
chosen depends on the "bioecology" of
the pest, and expresses the authors'
opinion that Iwao's procedure has several
advantages. The remaining sections include a glossary of symbols and references.
We found two mathematical errors in
this paper: (1) In the subsection of "Error
Levels" (p. 7), the authors define Type I
and Type II errors and the associated
error probabilities ex and 13. However, in
the subsection "Probability Curve" (p. 79), they do not use their definitions correctly. As such, in the formulas for LP (p.
9) and in Figure 2 (p. 8), where there is
an ex, there should be a 13 and vice versa;
(2) By definition of the operating characteristic curve and the average sample
number curve, the abscissa of the graphs
in Figures 2 and 3 should read "Population Mean," not "Sample Mean."
In reading the "Principles" sections, we
also had some difficulty interpreting formulas because not all mathematical variables were defined in the text. For those
not defined there, the reader is forced to
page back to the "Glossary of Symbols"
for a definition, making the interpretation
process rather awkward. Additionally,
other items such as logarithms were not
defined at all, i.e., the reader is left wondering whether to use base 10 logs or
Napierian logs in making calculations
(base 10 logarithms were actually used).
A computational plus for the paper is
the quick and easy way of roughly determining the shape of the average sample
number curve. The authors give formulas
for average sample number at four values
of the population mean, and an average
sampling curve can be sketched from calculated points. This shortcut method, al·
though not as accurate, is easier than
making the complex calculations recommended by Waters (1955, For. Sci. 1: 6879) and others.
With regard to satisfying the objectives
stated, this bulletin falls a little short of
the mark. Although advantages of the
Iwao procedure are presented clearly
enough, advantages of the Wald proce·
dure are not mentioned at all. Data in this
publication (Table 1) show that the advantage of the Wald procedure is requiring fewer samples to make a decision
than with the Iwao procedure. We feel
that this important advantage should have
been mentioned.
Overall, the concept of presenting the
Wald and Iwao techniques in a single publication is a good idea. Sequential Sampling for Pest Control Programs offers
useful formulas and background on both
procedures. The information presented in
this publication should be of value to researchers and IPM consultants and is an
embellishment of similar material presented in texts such as Ecological
Methods by T. R.E. Southwood.
Larry P. Pedigo
Department of Entomology
Jan W. van Schalk
Department of Statistics
Iowa State University
Ames, IA 50011
Ed. note.' Copies of this publication
are available from Dr. G. Boivin, Re-
search Branch, Agriculture Canada,
Saintjean-sur·Richelicu,
Case Postale
457, Quebec po, Canada
In a Patch of Frrcwecd
BERND
HEINRICH
A Biologist's Life
in the Field. Bernd Heinrich. 1984. Harvard University Press, Cambridge, Mass.
vii, 194 pp. $18.50.
IN A PATCH OF FlREWEED.
Bernd Heinrich is one of those unusual
individuals who, unlike most, rarely suffered the peer, parental, or academic pressures which often cause one to veer from
interests in observing the natural world.
In fact, it was probably the pressures of a
world at war, coupled with his father's interests in biology, which nurtured his
curiosity of natural phenomena and
BULLETIN OF THE ESA
strengthened his powers of observation.
The son of Gerd Heinrich, an amateur
biologist, spl'cimen collector, ichneumonkl spedalist, and gentleman farmer,
Bernd was encouraged in his early biological observations. A member of an emigrant family after World War II, Bernd was
not afflicted with those worldly distractions th.1t often lead a young child from
his natural curiosity of nature. In contrast,
he learned to rely on the diversity of nature and his powers of observation for enjoyment.
In this delightful book, written primarily for a popular audience, Heinrich
presents a brief autobiographical sketch of
his early childhood, followed by several
chapters which discuss his major biological observations. Chapter 1 deals with the
flight of his family from war-torn Poland
through Germany, where his father was a
soldier in the Luftwaffe. Eventually they
settled on a forest preserve near Hamburg
where they lived until Bernd was 10. At
times the story resembles that of an "Indiana Jones" adventure episode. It is here,
and in the nl'xt chapter, describing his
eventual move to Maine, that Heinrich
tells us of his early interests in the natural
sciences, and we get a feel for his remarkable observational powers. Of equal or
greater interest to his biological observations are his dl(mghts and experiences as
a child in post-war Europe.
Chapter 4 is one thac will be familiar to
a.ll past and present students as Heinrich
relates some of his personal experiences
as a student. I found this chapter enjoyable as it relates the trials most students
must pass through before a final product
is developed. It was at UClA that Heinrich
perfected his research techniques on
thermoregulatory mechanisms in insects.
In the remainder of the book, Heinrich
treats various research projects in which
he has been involved. Among others, his
topics have included honey bee swarming, African dung beetles, whirlygig beetil's, lepidopteran caterpillars, antlions,
baJdfaced hornets, yellowjackets, winteractive moths, and ants. With few exceptions, each of these chapters has insect
thermoregulation
as a central theme.
However, the discussions are much more
than just how an insect or a colony of
insects regulates its internal temperature.
Heinrich also relates thermoregulation to
the overall biology of the insects. In addition, he often postulates on the possible
evolutionary
pathways which led to
present-day adaptations.
Throughout the chapters Heinrich is
constantly relating his personal experiences and interesting observations, which
makes for thoroughly enjoyable reading.
WINTER 1984
Often the trials and experiences
one
passes through on the way to solving a
problem are more interesting than the
end product. In relating experiences, observing, and exploring, Heinrich is at his
best.
In the final chapter, Heinrich not only
presents the results of several biological
studies, but also gives his ideas on how
he prefers "to do science." To him, few,
if any projects are ends in themselves, but
all lead to further questions. Also, he believes that only through observing can we
truly understand nature.
I found this book to be very readable
and enjoyable. The writing style is one
which will be appreciated by professional
and lay naturalist alike. Because of its
modest price I strongly suggest the book
as a gift, especially for someone who enjoys the outdoors and observing nature.
The book is printed in a script style on a
Manila-colored paper, which gives it the
appearance of a field notebook. Additionally, it is interspersed with the author's
own pleasing drawings. The only noticeable flaw that 1found in the book is Heinrich's assertation that the Ichneumonidae
contains more species than any other
family of insects.
Richard S. Zack
Department
of Entomology
Washington State University
Pullman,
WA 99164
Insecticide & Acaricide
Tests Volume 9: 1984
The annual edition of Insecticide &
Acaricide Tests (IAn was recently
publiShed by ESA. The IAT is a comprehensive compilation of the most upto-date facts on efficacy and phytotoxicity of insecticides and acaricides,
and provides a permanent reference on
the performance of materials for insect
and mite control.
Volume 9 contains 568 reports,
presenting the results of tests on more
than 65 hosts. Field and laboratory
tests performed on a variety of fruits,
vegetable
and ornamental
crops,
stored products, trees, and livestock
are reported, filling the need for current
information
on insecticide
and
acaricide screening. Names and addresses for manufacturers
of test
materials are also supplied in the lAT.
This 502-page volume is available for
$15.00
(ESA members);
$22.00
(nonmembers). Past issues of the IAT,
for years 1976-1983 (Volumes 1-8)
are also available, for $15.00/$22.00
each volume.
To receive the editions you need,
send payment with your order (add 5%
sales tax if you reside in Maryland) to
ESA, Box 4104, Hyattsville, MD 20781.
New Releases from ESA
Miscellaneous Publications of the E.S.A.
The first 1984volume of Miscellaneous Publications, Number 58, was published in May.
"Revision of the Genus Archytas (Diptera: Tachinidae) for America North of Mexico"
contains useful information for identifying species on the basis of multiple characters in
both males and females. Authors F. William Ravlin and Frederick W. Stehr provide illustrations of male and female terminalia, a historical review of the Archytas genus for
North America, and keys and descriptions for the tribe Dejeaniini and the genus Archytas.
Copies of this comprehensive work are available for $4.50 each (ESA members)/$7 .50 each
(nonmembers). To receive yours, send payment with your order to ESA.
Bibliographies of the E.S.A.
The third and final volume in ESA's newest publication series, Bibliographies, was
published in June. It contains two papers, "Selected Bibliography of the Predaceous Mite,
Phytoseiulus persinilis Athias-Henriot (Acarina: Phytoseiidae)," by F. L. Petitt and L. S.
Osborne, and "Selected Bibliography of Insect Pests of Sorghum and Pearl Millet and
Their Natural Enemies in Africa," by R. T. Gahukar. This 33-page reference is available
for only $2.50, postpaid. Copies of Volume I and Volume 2 of Bibliographies are also
available for $2.50 each.
To order either of these new ESA books, send payment with your order (Maryland
residents, add 50/0 sales tax) to ESA, Box 4104, Hyattsville, MD 20781. A 110w 4-6 weeksfor
delivery.
65