Methods for the Study of Pest Diabrotica

271 Pages·1986·6.951 MB·English

by  James L. Krysan (auth.), James L. Krysan, Thomas A. Miller (eds.)

Springer Series in
Experimental Entomology
Thomas A. Miller, Editor
Springer Series in Experimental Entomology
Editor: T.A. Miller
Insect Neurophysiological Techl\iques
By T.A. Miller
Neuroanatomical Techniques
Edited by N.J. Strausfeld and TA. Miller
Sampling Methods in Soybean Entomology
Edited by M. Kogan and D. Herzog
Neurohormonal Techniques in Insects
Edited by TA. Miller
Cuticle Techniques in Arthropods
Edited by TA. Miller
Functional Neuroanatomy
Edited by N.J. Strausfeld
Techniques in Pheromone Research
Edited by H.E. Hummel and TA. Miller
Measurement of Ion Transport and Metabolic Rate in Insects
Edited by TJ. Bradley and TA. Miller
Neurochemical Techniques in Insect Research
Edited by H. Breer and TA. Miller
Methods for the Study of Pest Diabrotica
Edited by J.L. Krysan and TA. Miller
Insect-Plant Interactions
Edited by J .R. Miller and TA. Miller
Methods for
the Study of
Pest Diabrotica
Edited by
James L. Krysan
Thomas A. Miller
With Contributions by
J.F. Andersen M.K. Bergman T.F. Branson
J.R. Coats J.R. Fisher J.P. Fulton
R.C. Gergerich J.J. Jackson J.L. Krysan
ZB Mayo, Jf. W.G. Ruesink J.M. Schalk
H.A. Scott G.R. Sutter J.J. Tollefson
P.J. Wilkin
With a Foreword by R.L. Metcalf
With 68 Figures
Springer- Verlag
New York Berlin Heidelberg Tokyo
James L. Krysan Thomas A. Miller
USDA-ARS Department of Entomology
Yakima Agricultural Research University of California
Laboratory Riverside, California 92521
Yakima, Washington 98902 U.S.A.
U.S.A.
Library of Congress Cataloging-in-Publication Data
Main entry under title:
Methods for the study of pest Diabrotica.
(Springer series in experimental entomology)
Bibliography: p.
Includes index.
I. Diabrotica. 2. Diabrotica-Research-Technique.
I. Krysan, James L. II. Miller, Thomas A.
III. Andersen, J.F. IV. Series.
SB945.D48M47 1986 632'.764 85-22194
© 1986 by Springer-Verlag New York Inc.
Softcover reprint ofthe hardcover 1st edition 1986
All rights reserved. No part of this book may be translated or reproduced in
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as a sign that such names, as understood by the Trade Marks and Merchandise
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Copyright is not claimed for works by U.S. Government Employees: Chapters
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Typeset by David E. Seham Associates Inc., Metuchen, New Jersey.
9 8 7 6 5 4 3 2 1
ISBN-13: 978-1-4612-9338-5 e-ISBN-13: 978-1-4612-4868-2
DOl 10.1007/978-1-4612-4868-2
Series Preface
Insects as a group occupy a middle ground in the biosphere between bac
teria and viruses at one extreme, amphibians and mammals at the other.
The size and general nature of insects present special problems to the
study of entomology. For example, many commercially available instru
ments are geared to measure in grams, while the forces commonly en
countered in studying insects are in the milligram range. Therefore, tech
niques developed in the study of insects or in those fields concerned with
the control of insect pests are often unique.
Methods for measuring things are common to all sciences. Advances
sometimes depend more on how something was done than on what was
measured; indeed a given field often progresses from one technique to
another as new methods are discovered, developed, and modified. Just
as often, some ofthese techniques find their way into the classroom when
the problems involved have been sufficiently ironed out to permit students
to master the manipulations in a few laboratory periods.
Many specialized techniques are confined to one specific research lab
oratory. Although methods may be considered commonplace where they
are used, in another context even the simplest procedures may save con
siderable time. It is the purpose of this series (1) to report new devel
opments in methodology, (2) to reveal sources of groups who have dealt
with and solved particular entomological problems, and (3) to describe
experiments which may be applicable for use in biology laboratory courses.
THOMAS A. MILLER
Series Editor
Foreword
Among the Diabroticina beetles of the New World are found some of the
most destructive insect pests. The biology of these is discussed in some
detail by Krysan in Chapter 1 ofthis volume. In North America, the three
important species of corn rootworms, Diabrotica virgifera virgifera
LeConte, the western corn rootworm; D. barberi Smith and Lawrence,
the northern corn rootworm; and D. undecimpunctata howardi Barber,
the southern corn rootworm are probably the continent's most expensive
insect pests. Soil insecticides are routinely applied to 50-60% of the corn
(maize) acreage or as much as 30-40 million acres (12-16 million ha)
(Eichers et al., 1978). Present day costs of soil insecticide treatments range
from $15-20 per acre. During intensive outbreaks of corn rootworms, aerial
sprays are applied to as much as 10 million acres (4 million ha) (Chio et
aI., 1978) at an additional cost of about $4-5 per acre.
The root feeding of the beetles causes direct damage to corn growth
and corn yields. Corn rootworm infestations have been shown to decrease
yields of corn by 13-16 bu per acre or 10-13% (Apple, 1971; Kuhlman
and Petty, 1973). Thus the present day toll paid by U.S. farmers in treat
ment costs and crop losses is in the range of $1 billion per year.
Diabroticina attacking other crops such as Cucurbitaceae and Fabaceae
including D. u. howardi and D. u. undecimpunctata Mannerheim, the
western spotted cucumber beetle; D. balteata LeConte, the banded cu
cumber beetle; Acalymma vittatum (Fabricius), the striped cucumber
beetle; and A. trivittatum (Mannerheim), the western striped cucumber
beetle cause additional damage aggregating to $50-100 million (Metcalf et
aI., 1962).
viii Foreword
The magnitude of this toll is all the more shocking because it could be
largely eliminated by proper utilization of our present-day knowledge of
the bionomics and ecology of the rootworm beetles in the application of
integrated pest management (IPM) technology. Yearly crop rotation of
com with legumes such as soybeans, which are not a host plant for the
northern and western com rootworm larvae, is almost completely effective
in preventing corn rootworm damage (Metcalf et aI., 1962). Moreover,
while soil insecticides are routinely applied to over 60% of the corn land
in the major com belt states, careful studies have shown that the economic
threshold for rootworm damage is exceeded in only about 11-19% of the
total corn land (Luckmann, 1978). In Indiana from 1972 to 1974, where
40% of the corn acreage was treated for corn rootworm control, less than
10% required treatment (Turpin and Maxwell, 1976). An extensive study
in Nebraska over 1978 to 1980 (Stamm et aI., 1985), in an area where soil
insecticides were routinely used in 90% of the fields, showed that this use
could be reduced to 5.2-8.6% of the fields without serious corn rootworm
damage to corn.
It should be evident that U.S. farmers could save hundreds of millions
of dollars annually by implementing IPM practices with realistic economic
thresholds for corn root worm populations.
Diabroticina Resistance to Insecticides
The western corn rootworm provides the classic example of a man-made
pest. It was first described in 1868 by LeConte from specimens collected
from the flowers of Cucurbita foetidissima growing near Fort Wallace,
Kansas (Smith and Lawrence, 1966). D. virgifera was first found attacking
corn near Fort Collins, Colorado in 1909 (Gillette, 1912). It slowly spread
across the western corn growing area, producing injury in southwest Ne
braska in 1929 and extending eastward to Grand Island by 1945 (Tate and
Bare, 1946). It was reported as injurious in 1945 in Norton County, Kansas
and by 1953 it was found as far east as Nehama, Pottawattomie, Wa
baunsee, Morris, and Chase Counties (Burkhardt and Bryson, 1955). The
western corn rootworm crossed Nebraska to within 70 miles of the Mis
souri River by 1948 and by 1954 was present all along the river from South
Dakota to Missouri (Ball, 1957). Thus from 1909 to 1948 the species trav
eled eastward from Colorado to the Missouri River-about 470 miles
at an average of 12 miles per year. A map showing its rate of spread is
given by Metcalf (1983). During the 1953 growing season, the western
corn rootworm traveled eastward in Kansas 30 to 35 miles (Burkhardt
and Bryson, 1955).
Benzene hexachloride was recommended in Nebraska as a preplanting
soil insecticide to control corn rootworm larvae in 1948 and large-scale
applications were made in that state in 1949. Similar treatments were made
Foreword
IX
in Nebraska with aldrin and chlordane in 1952 and with heptachlor in 1954
(Ball, 1968; Ball and Weekman, 1962). The total area treated with these
soil insecticides in Nebraska in 1954 was 1,740,000 acres (Ball and Week
man, 1962). Ineffective corn rootworm control was first noted in south
central Nebraska in 1959 and became increasingly serious during 1960 and
1961. Western corn rootworm adult resistance to aldrin (100 x) and to
heptachlor (89 x) was demonstrated in 1961 by Ball and Weekman (1962).
The area infested by the resistant strain began to expand rapidly in an
80-100 mile wide band along the Platte River in east-central Nebraska
that reached into the western edges of South Dakota, Iowa, and Missouri
by 1962 (Ball and Weekman, 1963). A coordinated regional survey of the
spread of the cyclodiene-resistant race of western corn rootworms (Ham
ilton, 1965) showed that the resistant beetles were present in western Iowa,
northern Kansas, northwestern Missouri, southwestern Minnesota, and
southeastern South Dakota.
Surveys made by the USDA in 1956, 1965, 1969, 1975, and 1977 have
provided perhaps the best record of the migration of a species in which
resistance was induced in a single locality. It appears that the cyclodiene
resistant strain has altered behavioral characteristics and it spread rapidly
from a single locus in southeastern Nebraska in 1961 to encompass much
of the corn growing area of North Dakota, South Dakota, Nebraska, Iowa,
Kansas, Missouri, Wyoming, and Colorado by 1964. A map summarizing
the rate of distribution is given by Metcalf (1983). From 1961 to 1964 the
resistant race spread over the approximately 360 miles from near Grand
Island, Nebraska to near Eau Claire, Wisconsin, or an average of 120
miles per year. The cyclodiene-resistant strain reached northwest Indiana
by 1968, a distance of about 500 miles in 7 years, or about 70 miles per
year, and by 1980 had spread throughout the U.S. corn belt.
The astonishing increase in the rates of migration of this species from
the 12 to 30 miles per year recorded before the onset of resistance to the
70 to 120 miles per year after the resistant strains evolved, appears to be
the result of increased fitness of the resistant race and of a behavioral
change associated with the R-gene. The resistant beetles have become
superior competitors and by competitive displacement have become the
dominant rootworm pest in a large area of the com belt where the northern
corn root worm , D. barberi that inhabits an almost identical ecological
niche, was formerly the dominant pest (Ball and Weekman, 1963; Chiang,
1973). In Illinois, for example, in 1967 the western corn rootworm com
prised 9% of the corn rootworm population, in 1975, 35%, and in 1977,
65%, reaching 89-93% in some localities (Wedberg and Black, 1978).
The northern corn rootworm has also produced a cyclodiene-resistant
race (750 x to aldrin) appearing in Illinois in 1963, about 10 years after
the initiation of the large-scale usage of aldrin soil insecticide in 1953 (Big
ger, 1963). However, the resistant race has remained confined to specific
x Foreword
localities and was demonstrated in Wisconsin (Patel and Apple, 1966),
Ohio (Blair and Davidson, 1966), Iowa, South Dakota, and Minnesota
(Hamilton, 1965).
Corn rootworm resistance to the cyclodiene insecticides together with
cancellation of registrations of their use by the U.S. Environmental Pro
tection Agency for aldrin and dieldrin in 1974 and chlordane and heptachlor
in 1977 have had an adverse impact on the economics of corn rootworm
control. Between 1952 and 1962, the average cost of applications of aldrin
or heptachlor granulars at 1.5 Ib per acre was $2.20 (von Rumker et aI.,
1975), and the savings of corn were as high as 8.5 bu per acre (Bigger,
1963). At an average price for corn of$I.10 per bu (USDA data) the return
to the grower, neglecting externalities, was $4.25:$1.00. This relatively
cheap crop insurance became an acceptable grower practice without regard
to corn rootworm populations or economic thresholds. However, as cy
clodiene resistance spread, the use of aldrin in 1968-1970 saved only an
average of 1.6 bu per acre as compared to as much as 8.5 bu per acre in
1952-1962, and the average corn price was $1.33 per bu for a profitless
$1.00:$1.00. During the 1968-1970 period, the alternative use of carbofuran
soil insecticide at 1 lb per acre saved an average of 13.7 bu of com per
acre (Kuhlman and Petty, 1971). Thus in 1975 with com averaging $2.54
per bu, soil treatment with carbofuran costing $7.50 per acre saved as
much as $34.80 worth of com for a ratio of $4.09:$1.00 (von Rumker et
aI., 1975).
C.R. Taylor (see Metcalf, 1982, 1983) has devised a nomogram relating
the economic threshold in beetles per corn plant in the fall, to the ratio
of the price of com per bushel/cost of soil treatment. This carefully de
veloped study showed the economic threshold over the period 1952-1962
with aldrin treatment for a ratio of 0.50 was one adult rootworm per plant.
The ~witch to carbofuran and other more expensive organophosphates
and carbamates dramatically increased the economic threshold, e.g., in
1975 with carbofuran treatment the ratio was 0.3 giving an economic
threshold of 3 beetles per plant. In 1979 with soil treatment costs of $10
per acre and com averaging $2.20 per bu, the ratio was about 0.22 and
the economic threshold was 5 beetles per com plant (Metcalf, 1982). In
1984 with soil treatment costs approaching $20 per acre and the price of
com static at about $2.30, the ratio of about 0.11 corresponds to such a
high economic threshold that it exceeds the dimensions of the nomogram.
The present day control of corn rootworms with soil insecticides is
complicated by additional technological problems. Low levels of resistance
have developed to some of the newer replacement insecticides (Chio et
aI., 1978; Walgenbach and Hooten, 1980). Accelerated microbial degra
dation, where the soil microorganisms have developed a capacity to use
the soil insecticide as an energy source, has resulted in degradative rates
for carbofuran and other soil pesticides as much as 10-fold higher in prob-
Foreword xi
lem soils than in non-problem soils (Felsot et al., 1982; Kaufman and Ed
wards, 1983).
These adverse factors, together with legal restrictions of insecticide use,
have resulted in the withdrawal of recommendations for use between 1950
to 1983, of the following soil insecticides for corn rootworm control: ben
zene hexachloride, aldrin, dieldrin, heptachlor, chlordane, parathion, dia
zinon, disulfoton, fensulfothion, isofenphos, carbaryl, metalkamate, lan
drin, and carbofuran. Only a few new insecticides have been introduced
during the 1980s as replacements. Thus the prognosis for the long-term
continuation of successful soil insecticide control of rootworms is not
promising.
Chemical Ecology
Notable progress is being made in identifying the semiochemicals that
regulate Diabroticina behavior and in exploring their roles in monitoring
populations of corn rootworm beetles and in alternative strategies for con
trol. Chapter 4 of this volume by Andersen and Wilkin summarizes new
methodology for studying semiochemical isolation, identification, and be
havior. The female sex pheromone of D. virgifera virgifera has been iden
tified as (R-)-8-methyl-(R)-2-decylpropanoate (Guss et at., 1982) to which
D. barberi also responds (Guss et al., 1985). The sex pheromone of D.
undecimpunctata howardi is 1O-methyl-2-tridecanone (Guss et al., 1983).
Host plant selection by the rootworms is influenced by a variety of plant
volatiles. Indole has been identified as a volatile constituent of the very
attractive Cucurbita blossoms that produces oriented flight behavior by
D. v. virgifera and the striped cucumber beetle Acalymma vittatum (An
dersen and Metcalf, 1985). Eugenol or 3-methoxy-4-hydroxy-l-allylben
zene is a plant-produced kairomone that is highly attractive to the northern
corn rootworm adult, D. barberi (Ladd et al., 1983; Ladd, 1984).
Kairomone response among the corn rootworms appears to be highly
specific and estragole or 4-methoxy-l-allylbenzene is substantially at
tractive to adults of the western corn rootworm D. v. virgifera and veratrole
or o-dimethoxybenzene is attractive to those of the southern corn root
worm D. u. undecimpunctata (Lampman et al., 1985). Exploration of the
use of these volatile pheromones and kairomones in monitoring and trap
ping corn rootworm adults, e.g., by sticky traps (Hein and Tollofson, 1984),
offers an exciting new area for corn rootworm research. Sampling and
trapping techniques are discussed in Chapter 7 ofthis volume by Tollofson.
The entire group of Diabroticina appear to have coevolved with the
Cucurbitaceae and use the tetracyc1ic triterpenoid cucurbitacins as ar
restants and feeding stimulants (Metcalf, 1985a, b). Work in this area is
discussed by Andersen and Wilkin in Chapter 4. The various species of
rootworm adults can detect the presence of nanogram quantities of cu-