24
In
s
ect
s
an
d
Human
s
1
. Intr
oduc
t
ion
T
his final chapter will focus on those insects that humans describe, in their economicall
y
minded wa
y
, as beneficial or harmful, thou
g
h it should be appreciated from the outset that
t
hese constitute onl
y
aver
y
small fraction of the total number of species. It must als
o
b
e rea

li
ze
d
t
h
at t
h
e eco
l
og
i
ca
l
pr
i
nc
i
p
l
es govern
i
ng t
h
e
i
nteract
i
ons
b
etween

i
nsects an
d
h
umans are no
diff
erent
f
rom t
h
ose
b
etween
i
nsects an
d
any ot
h
er
li
v
i
ng spec
i
es, eve
n
th
ou
gh h
umans w

i
t
h
t
h
e
i
rmo
d
ern tec
h
no
l
o
gy
can mo
dify
cons
id
era
bly
t
h
e nature o
f
t
h
es
e
interactions

.
Of an estimated 5–10 million species of insects, probabl
y
not more than a fraction o
f
1%
i
nteract,
di
rect
l
yor
i
n
di
rect
l
y, w
i
t
hh
umans. Per
h
aps some 10,000 const
i
tute pests t
h
at
,
e

i
t
h
er a
l
one or
i
n con
j
unct
i
on w
i
t
h
m
i
croorgan
i
sms, cause s
i
gn
ifi
cant
d
amage or
d
eat
h
t

o
h
umans, a
g
r
i
cu
l
tura
l
or
f
orest pro
d
ucts, an
d
manu
f
acture
dg
oo
d
s. Wor
ld
w
id
e
f
oo
d

an
dfib
er
losses caused b
y
pests (principall
y
insects, plant patho
g
ens, weeds, and birds) are
g
enerall
y
estimated at about 40%, of which 12% are attributable to insects and mites. These fi
g
ures do
not
i
nc
l
u
d
e
p
ost
h
arvest
l
osses, est
i

mate
d
to
b
ea
b
out 20%, an
d
occur
d
es
pi
te t
h
ea
ppli
cat
i
on
of about 3 million tonnes of pesticide (worth more than US$31 billion, including abou
t
US$9 billion of insecticide) (Pimentel, 2002). In the United States alone, crop losses relate
d
t
o insect dama
g
e rose from 7% to 13% in the period 1945–1989, despite a tenfold increase
in the amount of insecticide used
(
>

120,000 tonnes each
y
ear) (Pimente
l
et al.
, 1992)
.
On t
h
eot
h
er
h
an
d
,t
h
eva
l
ue o
fb
ene
fi
ts
d
er
i
ve
df
rom

i
nsects
i
s severa
lf
o
ld
t
h
at o
fl
osses
as a resu
l
to
f
t
h
e
i
rpo
lli
nat
i
ng act
i
v
i
ty, t
h

e
i
rro
l
e
i
n
bi
o
l
og
i
ca
l
contro
l
,an
d
t
h
e
i
r
i
mportance a
s
h
one
y
,s

ilk
,an
d
wax pro
d
ucers. T
h
at
i
nsects
d
o more
g
oo
d
t
h
an
h
arm pro
b
a
bly
wou
ld
com
e
as a surprise to la
y
persons whose familiarit

y
with insects is normall
y
limited to mosquitoes,
h
ouseflies, cockroaches, various
g
arden pests, etc., and to farmers who must protect thei
r
livestock and crops against a variety of pests. If asked to prepare a list of useful insects, man
y
peop
l
e most
lik
e
l
ywou
ld
not get
f
urt
h
er t
h
an t
h
e
h
oney

b
ee an
d
, per
h
aps, t
h
es
ilk
mot
h
,an
d
w
ou
ld
ent
i
re
l
y over
l
oo
k
t
h
e enormous num
b
er o
f

spec
i
es t
h
at act as po
lli
nat
i
ng agents or
pre
y
on harmful insects that mi
g
ht otherwise reach pest proportions.
H
umans have lon
g
reco
g
nized the importance of insects in their well-bein
g
. Insects
and/or their products have been eaten by humans for thousands of years. Production of sil
k
from silkmoth pupae has been carried out for almost
5
000 years. Locust swarms, which
7
2
5

72
6
CHAPTER
24
o
ri
g
inall
y
ma
y
have beenan important seasonal food for humans, took on new si
g
nificance as
humans turned to a farmin
g
rather than a huntin
g
existence. However, with rare exceptions,
f
or example, the hone
y
bee and silkmoth whose mana
g
ement is relativel
y
simple and labor
-
i
ntens

i
ve, unt
il
recent
l
y
h
umans ne
i
t
h
er
d
es
i
re
d
nor were a
bl
e,
b
ecause o
f
a
l
ac
k
o
fb
as

i
c
k
now
l
e
d
ge as we
ll
as tec
h
no
l
ogy, to attempt
l
arge-sca
l
emo
difi
cat
i
on o
f
t
h
eenv
i
ronmen
t
o

f insects
,
either to increase the number of beneficial insects or to decrease the number of
those desi
g
nated as pests
.
Several features of recent human evolution have made such attem
p
ts im
p
erative. These
i
nc
l
u
d
e a mass
i
ve
i
ncrease
i
n popu
l
at
i
on, a tren
d
towar

d
ur
b
an
i
zat
i
on,
i
ncrease
d
geograp
hic
m
ovement o
f
peop
l
ean
d
agr
i
cu
l
tura
l
pro
d
ucts, an
d

, assoc
i
ate
d
w
i
t
h
t
h
e nee
d
to
f
ee
d
more
peop
l
e, a tren
d
towar
d
monocu
l
ture as an a
g
r
i
cu

l
tura
l
pract
i
ce.
T
he relativel
y
crowded conditions of urban areas enable insects parasitic on humans
both to locate a host (frequentl
y
a prerequisite to reproduction) and to transfer between hos
t
i
n
di
v
id
ua
l
s. T
h
us, ur
b
an
i
zat
i
on

f
ac
ili
tates t
h
es
p
rea
d
o
fi
nsect-
b
orne
h
uman
di
seases suc
h
as typ
h
us, p
l
ague, an
d
ma
l
ar
i
aw

h
ose spectacu
l
ar e
ff
ects on
h
uman popu
l
at
i
on are we
ll
d
ocumente
d
. For examp
l
e,
i
nt
h
es
i
xt
h
centur
y
A.D. p
l

a
g
ue was respons
ibl
e
f
or t
h
e
d
eat
h
o
f about 50% of the
p
o
p
ulation in the Roman Em
p
ire, and “Black Death” killed a similar
proportion of En
g
land’s population in the mid-1300s (Southwood, 1977).
An
i
ncreas
i
ng nee
d
to pro

d
uce more an
d
c
h
eaper
f
oo
dl
e
d
,t
h
roug
h
agr
i
cu
l
tura
l
mec
h
-
an
i
zat
i
on, to t
h

e pract
i
ce o
f
monocu
l
ture, t
h
e grow
i
ng o
f
a crop over t
h
e same
l
arge area o
f
l
an
df
or man
yy
ears consecut
i
ve
ly
. However, two
f
au

l
ts o
f
monocu
l
ture are (1) t
h
e ecos
y
s
-
tem is simplified and (2) as the crop plant is frequentl
yg
raminaceous (a member of the
g
ras
s
f
amil
y
, includin
g
wheat, barle
y
, oats, rice, and corn), the ecos
y
stem is artificiall
y
maintained
at an ear

l
y stage o
f
eco
l
og
i
ca
l
success
i
on. By s
i
mp
lif
y
i
ng t
h
e ecosystem,
h
umans encourage
t
h
e
b
u
ild
up o
f

popu
l
at
i
ons o
f
t
h
e
i
nsects t
h
at compete w
i
t
h
t
h
em
f
or t
h
e
f
oo
db
e
i
ng grown.
Furt

h
er,ast
h
e compet
i
ng
i
nsects are pr
i
mary consumers, t
h
at
i
s, near t
h
e start o
f
t
h
e
f
oo
d
c
hain, the
y
t
y
picall
y

haveahi
g
h reproductive rate and short
g
eneration time. In other words
,
p
o
p
ulations of such s
p
ecies have the
p
otential to increase at a ra
p
id rate
.
A massive increase in human geographic movements and a concomitant increase i
n
tra
d
e
l
e
d
to t
h
e transp
l
antat

i
on o
f
a num
b
er o
f
spec
i
es,
b
ot
h
p
l
ant an
d
an
i
ma
l
,
i
nto area
s
prev
i
ous
l
y unoccup

i
e
db
yt
h
em. Some o
f
t
h
ese were a
bl
e to esta
bli
s
h
t
h
emse
l
ves an
d,
i
n the absence of normal re
g
ulators of population (especiall
y
predators and parasitoids)
,
i
ncreased rapidl

y
in number and became important pests. Sometimes, as humans colonized
n
ew areas, some of the cultivated
p
lants that were introduced
p
roved to be an excellent food
f
or s
p
ec
i
es o
fi
nsects en
d
em
i
ctot
h
ese areas. For exam
pl
e, t
h
eCo
l
ora
d
o

b
eet
l
e,
L
ept
i
notarsa
d
ecem
l
ineata
,
w
a
sor
i
g
i
na
ll
y restr
i
cte
d
to t
h
e sout
h
ern Roc

k
y Mounta
i
ns an
df
e
d
on w
ild
S
o
l
anaceae. W
i
t
h
t
h
e
i
ntro
d
uct
i
on o
f
t
h
e potato
by

sett
l
ers, t
h
e
b
eet
l
e
h
a
d
an a
l
ternate, mor
e
e
asil
y
accessible source of food, as a result of which both the abundance and distribution of
the beetle increased and the species became an important pest. Likewise, the apple ma
gg
ot,
Rh
a
g
o
l
etis pomone
lla

,
apparent
l
y
f
e
d
on
h
awt
h
orn unt
il
app
l
es were
i
ntro
d
uce
di
nto t
h
e
e
astern United States (Horn, 197
6
)
.
2

. Beneficial Insect
s
Insects may
b
ene
fi
t
h
umans
i
nvar
i
ous ways,
b
ot
hdi
rect
l
yan
di
n
di
rect
l
y. T
h
e most
ob
v
i

ous o
f
t
h
e
b
ene
fi
c
i
a
l
spec
i
es are t
h
ose w
h
ose pro
d
ucts are commerc
i
a
lly
va
l
ua
bl
e.
Considerabl

y
more important, however, are the insects that pollinate crop plants. Othe
r
7
27
I
N
S
E
C
T
SA
ND
HUM
A
NS
b
eneficial insects are those that are used as food, for biolo
g
ical control of pest insects and
plants, in medicine and in research. For some of these useful species, humans modif
y
their
environment so as to increase their distribution and abundance in order to
g
ain the benefits
.
2
.1. Insects Whose Products Are
C

ommerc
i
ally Valuabl
e
The best-known insects in this category are the honey bee (
Apis mellifera
(
(
)
, silkworm
(
B
ombyx mor
i
), lac insect (
L
acci
f
er lacc
a
)
, and
p
ela wax scale
(
Ericerus pel
a
).
T
h

e
h
oney
b
ee or
i
g
i
na
ll
y occup
i
e
d
t
h
eA
f
r
i
can cont
i
nent, most o
f
Europe (except t
h
e
nort
h
ern part), an

d
western As
i
a, an
d
w
i
t
hi
nt
hi
s area t
h
e use
f
u
l
ness o
fi
ts pro
d
ucts,
h
oney
an
db
eeswax,
h
as
b

een
k
nown
f
or man
y
t
h
ousan
d
so
fy
ears. T
h
ou
gh
t
h
e
di
scover
y
o
f
su
g
a
r
in cane (in India, about 500 B.C.) and in beet (in Europe, about 1800 A.D.) (Southwood,
1977) led to a decline in the importance of hone

y
, it is nevertheless still a ver
y
valuable
p
roduct
.
Bee management was pro
b
a
bl
y
fi
rst carr
i
e
d
out
b
yt
h
e anc
i
ent Egypt
i
ans. Honey
b
ees
w
ere brought to North America by colonists in the early l

6
00s, and today honey an
d
b
eeswax production is a billion dollar industr
y
. In 2001 world hone
y
production was esti-
mated at about 1.25 million tonnes and a value of about US
$
4 billion. China is the world’
s
largest honey producer, accounting for almost 20% of the total; the United States lies i
n
thi
r
d
p
l
ace (
b
e
hi
n
d
t
h
e
f

ormer USSR), pro
d
uc
i
ng a
b
out 100,000 tonnes (w
i
t
h
ava
l
ue o
f
about US$330 million
)(
www.
b
ee
k
eepin
g
.com/
d
ata
b
ases/
h
one
y

-mar
k
et/wor
ld
h
one
y
.
h
tm
)
.
B
eeswax is produced at the rate of about 1 k
g
for ever
y
50–100 k
g
of hone
y
; its value per
k
ilo
g
ram varies between one and three times that of hone
y
. There is a si
g
nificant worl

d
trade, perhaps worth about US
$
10 million annually, in pollen which is used not only b
y
b
ee
k
eepers to supp
l
ement t
h
e reserves
i
nt
h
e
hi
ve
b
ut a
l
so
i
nt
h
e
h
ea
l

t
h
-
f
oo
di
n
d
ustry
.
O
ther products that are collected include propolis (bee
g
lue), venom (used to desensitiz
e
patients with severe aller
g
ies to bee stin
g
s), and ro
y
al
j
ell
y
which is added to certain foo
d
su
pp
lements (Gochnauer, in Pimentel, 1991, Vol. 2).

Goo
db
ee management a
i
ms to ma
i
nta
i
na
h
oney
b
ee co
l
ony un
d
er opt
i
mum con
di
t
i
on
s
f
or max
i
mum pro
d
uct

i
on. Mana
g
ement
d
eta
il
svar
y
accor
di
n
g
to t
h
ec
li
mate an
d
custom
s
o
f different
g
eo
g
raphical areas but ma
y
include (1) movin
g

hives to locations where nectar
-
producin
g
plants are plentiful, (2) artificial feedin
g
of newl
y
established, sprin
g
colonie
s
wi
t
h
sugar syrup
i
nor
d
er to
b
u
ild
up co
l
ony s
i
ze
i
nt

i
me
f
or t
h
e summer nectar
fl
ow
,
(
3) c
h
ec
ki
ng t
h
at t
h
e queen
i
s
l
ay
i
ng we
ll
an
d
,
if

not, rep
l
ac
i
ng
h
er, (4) c
h
ec
ki
ng an
d
treatin
g
colonies for diseases such as foulbrood and nosema, and (
5
) increasin
g
the size o
f
ah
iv
eas
the colon
y
develops, in order to prevent swarmin
g.
Silk production has been commercially important for about 4700 years. The industr
y
o

r
i
g
i
nate
di
n East As
i
aan
d
sprea
di
nto Europe (France, Ita
l
y, an
d
Spa
i
n) a
f
ter eggs wer
e
smugg
l
e
df
rom C
hi
na to Ita
l

y
i
nt
h
es
i
xt
h
century A.D. T
h
e pro
d
uct
i
on o
f
s
ilk
rema
i
n
s
a labor-intensive industr
y
, makin
g
production costs hi
g
h. In 1988 world silk productio
n

totaled about 67,000 tonnes, with raw silk fetchin
g
about US
$
50 per kilo
g
ram. B
y
the en
d
of
1998, pro
d
uct
i
on
h
a
di
ncrease
d
s
li
g
h
t
l
y, to 72,000 tonnes, t
h
oug

h
t
h
epr
i
ce o
f
raw s
ilk h
a
d
f
allen to about US$26 per kilogram due to competition from cheaper synthetic fibers. Chin
a
i
st
h
e
l
ea
di
n
g
pro
d
ucer, w
i
t
h
a

b
out 70% o
f
t
h
ewor
ld
tota
l
,an
d
In
di
a
h
as passe
d
Japan a
s
the world’s second lar
g
est producer (Feltwell, 1990
;
www.tradeforum.org/news/fullstor
y
)
.
T
he lac insect is a scale insect endemic to India and
S

outheast Asia that secretes abou
t
i
tse
lf
a coat
i
ng o
fl
ac, w
hi
c
h
may
b
e more t
h
an1cmt
hi
c
k
.T
h
etw
i
gs on w
hi
c
h
t

h
e
i
nsect
s
rest are co
ll
ecte
d
an
d
e
i
t
h
er use
d
to sprea
d
t
h
e
i
nsects to new areas or groun
d
up an
dh
eate
d
7

28
CHAPTER
24
i
n order to separate the lac. The lac is a component of shellac, thou
g
h its importance ha
s
declined considerabl
y
with the development of s
y
nthetic materials
.
T
he
p
ela wax scale has been used in China for commercial
p
roduction of “China wax,
”
pr
i
nc
i
pa
ll
y
i
nS

i
c
h
uan prov
i
nce,
f
or more t
h
an 1000 years. It
i
st
h
e secon
d
-
i
nstar ma
l
es t
h
at
pro
d
uce econom
i
ca
ll
yva
l

ua
bl
e wax. T
h
ese are care
f
u
ll
y manage
di
n
l
arge aggregat
i
on
s
(
200 per c
m
2
,
and extendin
g
a distance of 1.0–1.
5
m alon
g
a branch) that produce a coatin
g
o

f wax some 5–10 mm thick. Wax production peaked in the earl
y
1900s and in a
g
oo
d
y
ear was more than 6000 tonnes. Most of this wax was used in the manufacture of candles
.
S
tart
i
ng
i
nt
h
e 1940s, w
i
t
h
t
h
e com
i
ng o
f
e
l
ectr
i

c
i
ty an
ddi
scovery o
f
ot
h
er waxes (nota
bl
y
paraffin wax), interest in China wax production declined, and currently about
5
00 tonne
s
i
s
h
arveste
dy
ear
ly
.It
i
s use
df
or a var
i
et
y

o
fi
n
d
ustr
i
a
l
,p
h
armaceut
i
ca
l
,an
dh
ort
i
cu
l
tura
l
p
ur
p
oses, for exam
p
le, the manufacture of molds for
p
recision instruments, insulation o

f
e
lectrical cables and equipment, production of hi
g
h-
g
loss, tracin
g
, and wax paper, as a
n
i
ngre
di
ent o
ff
urn
i
ture an
d
automo
bil
epo
li
s
h
es, coat
i
ng can
di
es an

d
p
ill
s, an
d
as a gra
f
t
i
ng
agent
f
or
f
ru
i
t trees (Q
i
n,
i
n Ben-Dov an
d
Ho
d
gson, 1994)
.
2.2. In
sec
t
sas

P
o
ll
i
n
a
t
o
r
s
As was noted in Cha
p
ter 23, Section 3.2, an intimate, mutualistic relationshi
p
ha
s
ev
o
l
ve
db
etween many spec
i
es o
fi
nsects an
d
p
l
ants,

i
nw
hi
c
h
p
l
ants pro
d
uce nectar an
d
po
ll
en
f
or use
b
y
i
nsects, w
hil
et
h
e
l
atter prov
id
e a transport system to ensure e
ff
ect

i
ve cross-
pollination. Thou
g
h some crop plants are wind-pollinated, for example, cereals, a lar
ge
n
umber, includin
g
fruits, ve
g
etables, and field crops such as clovers, rape, and sunflower,
re
q
uire the service of insects. In addition, ornamental flowers are almost all insect-
p
ollinated
.
Th
e
b
est
k
nown, t
h
oug
hb
y no means t
h
eon

l
y,
i
mportant
i
nsect po
lli
nator
i
st
h
e
h
oney
b
ee, an
di
t
i
s stan
d
ar
d
pract
i
ce
i
n many parts o
f
t

h
ewor
ld f
or
f
ru
i
t, see
d
,an
d
vegeta
bl
e
pro
d
ucers e
i
t
h
er to set up t
h
e
i
rown
b
ee
hi
ves
i

nt
h
e
i
r orc
h
ar
d
san
dfi
e
ld
s or to contract t
his
j
ob out to beekeepers. For example, in California about 1.4 million hives are rented annuall
y
to au
g
ment natural pollination of almonds (about 50% of the hives), alfalfa, melons, an
d
o
t
h
er
f
ru
i
ts an
d

vegeta
bl
es (P
i
mente
l
e
ta
l.
,
1992). Un
d
er suc
h
con
di
t
i
ons, t
h
eva
l
ue o
fb
ees
as po
lli
nators may
b
eupto140t

i
mes t
h
e
i
rva
l
ue as
h
oney pro
d
ucers. Us
i
ng t
hi
s
f
actor,
it
i
s est
i
mate
d
t
h
at t
h
e
i

ncrea
s
e
d
v
a
l
ue o
f
crops attr
ib
uta
bl
eto
h
one
yb
ee po
lli
nat
i
on
i
nt
h
e
United States is about US
$
15 billion each
y

ear [see Robinson
et al.
(
1989
)
for a detaile
d
anal
y
sis]. This estimate does not take into account the value of other, natural pollinators
o
f crops, nor obviously has a value been placed on the importance o
f
a
l
l
p
ollinators o
f
n
on-crop p
l
ants, w
hi
c
h
are v
i
ta
l

to spec
i
es
di
vers
i
ty an
d
as
f
oo
df
or w
ildlif
e.
2.3. Insects as A
g
ents o
f
B
i
olo
gi
cal
C
ontrol
It is only relatively recently that humans have gained an appreciation of the importanc
e
of i
nsects

i
nt
h
eregu
l
at
i
on o
f
popu
l
at
i
ons o
f
potent
i
a
ll
y
h
arm
f
u
l
spec
i
es o
fi
nsects an

d
p
l
ants. In many
i
nstances, t
hi
s apprec
i
at
i
on was ga
i
ne
d
on
l
yw
h
en, as a resu
l
to
fh
uman
act
i
v
i
t
y

,t
h
e natura
l
re
g
u
l
ators were a
b
sent, a s
i
tuat
i
on t
h
at was rap
idly
exp
l
o
i
te
dby
t
h
ese
species whose status was soon elevated to that of pest. In the first three examples
g
ive

n
below (taken from DeBach and Rosen, 1991), none of the or
g
anisms is a pest in its countr
y
of
or
i
g
i
n
b
ecause o
f
t
h
e occurrence t
h
ere o
f
var
i
ous
i
nsect regu
l
ators. T
h
e
di

scovery o
f
t
h
ese regu
l
ators,
f
o
ll
owe
db
yt
h
e
i
r success
f
u
l
cu
l
ture an
d
re
l
ease
i
nt
h

e area w
h
ere t
h
e pest
o
ccurs, const
i
tutes
bi
o
l
o
gi
ca
l
contro
l
(Sect
i
on 4.3).
7
29
I
N
S
E
C
T
SA

ND
HUM
A
NS
Amon
g
the best-known examples of an introduced plant pest are the prickl
y
pear cacti
(
Op
untia
s
pp.) taken into Australia as ornamental plants b
y
earl
y
settlers. Once established
,
t
he plants spread rapidl
y
so that b
y
1925 some 60 million acres of land were infested,
most
l
y
i
n Queens

l
an
d
an
d
New Sout
h
Wa
l
es. Surveys
i
n
b
ot
h
Nort
h
an
d
Sout
h
Amer
i
ca,
wh
er
e
Op
untia
s

pp. are endemic, revealed about 1
5
0 species of cactus-eating insects, of
w
hich about
5
0 were
j
ud
g
ed to have biolo
g
ical control potential and were subsequentl
y
sent to Australia for culture and trials. Larvae of one s
p
ecies,
C
actoblastis cactoru
m
,a
moth, brou
g
ht from Ar
g
entina in Januar
y
, 1925, proved to have the required qualities and
wi
t

hi
n 10 years
h
a
d
v
i
rtua
ll
y
d
estroye
d
t
h
e cact
i
(F
i
gure 24.1). Per
h
aps t
h
e most remar
k
a
ble
feature of this success story is that only 27
5
0

C
acto
bl
astis
l
arvae were
b
roug
h
t to Austra
li
a
,
o
f
w
hi
c
h
on
l
y 1070
b
ecame a
d
u
l
ts. From t
h
ese,

h
owever, more t
h
an 100,000 eggs were
produced, and in Februar
y
–March of 192
6
more than 2.2 million e
gg
s were released in
t
he field! Additional releases, and redistribution of almost 400 million field-produced e
gg
s
u
ntil the end of 1929, ensured the project’s success
.
T
h
ec
l
ass
i
ca
l
examp
l
eo
f

an
i
nsect pest
b
roug
h
tun
d
er
bi
o
l
og
i
ca
l
contro
li
st
h
e cottony-
cus
hi
on sca
l
e
,
I
cer
y

a purc
h
as
i
,
w
hi
c
h
was
i
ntro
d
uce
di
nto Ca
lif
orn
i
a, pro
b
a
bl
y
f
rom
Australia, in the l8
6
0s. Within 20
y

ears, the scale had virtuall
y
destro
y
ed the recentl
y
established, citrus-fruit industr
y
in southern California. As a result of correspondence be
-
t
ween American and Australian entomologists and of a visit to Australia by an America
n
entomo
l
og
i
st, A
lb
ert Koe
b
e
l
e, two
i
nsect spec
i
es were
i
ntro

d
uce
di
nto t
h
eUn
i
te
d
State
s
as
bi
o
l
og
i
ca
l
contro
l
agents
f
or t
h
e sca
l
e. T
h
e

fi
rst,
i
n 1887, was Cr
y
ptoc
h
aetum icer
y
a
e
,
a parasitic fl
y
, about which little is heard, thou
g
h DeBach and Rosen (1991) consider tha
t
it had excellent
p
otential for control of the scale had it alone been im
p
orted. However, th
e
abilities of this species appear to have been lar
g
el
y
i
g

nored with the discover
y
b
y
Koebele o
f
th
eve
d
a
li
a
b
eet
l
e
,
Ro
d
o
l
ia car
d
ina
l
i
s
, feeding on the scale. In total, only 514 vedalia were
b
roug

h
t
i
nto t
h
eUn
i
te
d
States,
b
etween Novem
b
er 1888 an
d
Marc
h
1889, to
b
ecu
l
ture
d
on
ca
g
e
d
trees
i

n
f
este
d
w
i
t
h
sca
l
e. B
y
t
h
een
d
o
f
Ju
ly
1889, t
h
eve
d
a
li
a
h
a
d

repro
d
uce
d
to suc
h
an extent that one orchardist, on whose trees about 150 of the im
p
orted beetles had been
placed for culture, reported havin
g
distributed 63,000 of their descendants since June 1! B
y
1890, t
h
e sca
l
e was v
i
rtua
ll
yw
i
pe
d
out. S
i
m
il
ar successes

i
n contro
lli
ng sca
l
e
b
y means o
f
v
e
d
a
li
ao
r
C
r
y
ptoc
h
aetu
m
have been reported from more than 60 countries (Hokkanen, in
P
i
mente
l
, 1991, Vo
l

.2
)
.
A third example of an introduced pest bein
g
brou
g
ht under control b
y
biolo
g
ical a
g
ents
is the winter moth, Operophtera brumata, which, thou
g
h endemic to Europe and parts of
Asia, was accidentally introduced into Nova Scotia in the 1930s. Its initial colonization wa
s
slow, and it did not reach economically significant proportions until the early 19
5
0s, and b
y
19
6
2 it had spread to Prince Edward Island and New Brunswick. The larvae of the winter
moth feed on the folia
g
e of hardwoods such as oak and apple. Thou
g

h more than
6
0 para-
sites of the winter moth are known in western Europe, onl
y
6 of these were considered to be
potential control agents and introduced into eastern Canada between 1955 and 1960. Two
o
f
t
h
ese, C
y
zenis a
lb
icans
,
a tac
hi
n
id
,an
d
Ag
r
y
pon flaveo
l
atu
m

,an
i
c
h
neumon
id
,
b
ecame
established, but between them they brought the moth under control by 19
6
3. Embree (i
n
Hu
ff
a
k
er, 1971) note
d
t
h
at t
h
e two paras
i
tes are
b
ot
h
compat

ibl
ean
d
supp
l
ementar
y
t
o
each other. When the densit
y
of moth larvae is hi
g
h, C
.
a
lbicans, which is attracted to
,
and la
y
s its e
gg
s near, feedin
g
dama
g
e caused b
y
the larvae, is a more efficient parasite
tha

n
A
. flaveo
l
atum
.
H
owever, once
i
nt
h
ev
i
c
i
n
i
ty o
fd
amage,
i
t
d
oes not spec
ifi
ca
ll
y see
k
out w

i
nter mot
hl
arvae. T
h
us, at
l
ower
d
ens
i
ty,
i
t wastes eggs on non-suscept
ibl
e
d
e
f
o
li
a-
t
ors suc
h
as caterp
ill
ars o
f
t

h
e
f
a
ll
can
k
erworm
,
Al
so
ph
i
l
a
p
ometaria. Hence
,
at
l
ow
h
ost
7
30
CHAPTER
24
F
I
GU

RE 24.1.
(
A
)
C
actoblastis cactorum caterpillars feeding on cactus pad; and cactus-infested pasture before
(B) an
d
a
f
ter (C) re
l
ease o
f
C
acto
bl
asti
s
.
[
From D. F. Water
h
ouse, 1991, Insects an
dh
umans
i
n Austra
li
a,

i
n: T
h
e
I
nsects o
f
Austra
l
i
a
,
2n
d
e
d
., Vo
l
. 1 (CSIRO, e
d
.), Me
lb
ourne Un
i
vers
i
t
y
Press. B
y

perm
i
ss
i
on o
f
t
h
eD
i
v
i
s
i
on o
f
Entomology, CSIRO.
]
7
31
I
N
S
E
C
T
SA
ND
HUM
A

NS
d
ensities
,
A.
fl
aveolatu
m
is more effective because it oviposits specificall
y
on winter moth
larvae.
The three examples described above indicate one method whereb
y
the importance o
f
bi
o
l
og
i
ca
l
contro
l
can
b
e
d
emonstrate

d
, name
l
y,
b
y
i
ntro
d
uct
i
on o
f
potent
i
a
l
pests
i
nto areas
wh
ere natura
l
regu
l
ators are a
b
sent. Anot
h
er way o

fd
emonstrat
i
ng t
h
e same p
h
enomenon
i
sto
d
estro
y
t
h
e natura
l
re
g
u
l
ators
i
nt
h
eor
igi
na
lh
a

bi
tat, w
hi
c
h
ena
bl
es potent
i
a
l
pest
s
t
o under
g
o a population explosion. This has been achieved frequentl
y
throu
g
h the use of
non-selective insecticides. For example, the use of DDT a
g
ainst the codlin
g
moth
,
Cydi
a
p

omone
ll
a,
i
n
th
ewa
l
nut orc
h
ar
d
so
f
Ca
lif
orn
i
a,
l
e
d
to out
b
rea
k
so
f
nat
i

ve
f
roste
d
sca
l
e,
Lecanium pruinosum
,
w
hi
c
h
was una
ff
ecte
db
y DDT, w
h
ereas
i
ts ma
i
n pre
d
ator, an en-
cyrt
id
,
M

etap
h
ycus ca
l
ifornicus
,
su
ff
ere
dhi
g
h
morta
li
ty (Hage
n
et a
l.
,in
Hu
ff
a
k
er, 1971
)
.
Another
Leca
n
iu

m
s
cale
,
L
. coryli
,
introduced from Europe in the 1
6
00s, is a potentiall
y
serious pest of apple orchards in Nova Scotia but is normall
y
re
g
ulated b
y
various natural
parasitoids (especially the chalcidoid
s
B
lastothrix serice
a
a
n
d
Coccophagu
s
s
p

.) and
p
reda-
t
ors (especially mirid bugs). Experimentally it was clearly demonstrated in the 1960s that
app
li
cat
i
on o
f
DDT
d
estroye
d
a
l
arge proport
i
on o
f
t
h
e B
l
a
s
tot
h
ri

x
an
d
m
i
r
id
popu
l
at
i
on,
and this was followed in the next two
y
ears b
y
medium to heav
y
scale infestations. Recover
y
of the parasite and predators was rapid, however, and b
y
the third
y
ear after spra
y
in
g
the
scale population density had been reduced to its original value (MacPhee and MacLellan

,
i
nHu
ff
a
k
er, 1971).
2
.
4
.In
sec
t
sas
H
u
m
a
nF
ood
As noted in the previous chapter, insects pla
y
ake
y
role in ener
gy
flow throu
g
h the
ecosystem, pr

i
nc
i
pa
ll
yas
h
er
bi
vores
b
ut a
l
so as pre
d
ators or paras
i
tes, w
hi
c
h
may t
h
em-
se
l
ves
b
e consume
db

y
hi
g
h
er-
l
eve
li
nsect
i
vorous verte
b
rates. In turn, some o
f
t
h
ese ver-
t
e
b
rates, nota
bly f
res
h
water
fi
s
h
an
dg

ame
bi
r
d
s, are eaten
by h
umans. Moreover,
i
n man
y
parts of the world, insects (includin
gg
rasshoppers and locusts, beetle larvae, caterpillars,
b
rood of ants, wasps and bees, termites, cicadas, and various aquatic species) historicall
y
played, and continue to have, an important part as a normal component of the human diet
(DeFo
li
art, 1992, 1999).
A
b
or
i
g
i
na
l
peop
l

eo
f
t
h
e Great Bas
i
nreg
i
on
i
nt
h
e sout
h
western Un
i
te
d
States tra
-
d
itionall
y
spent much time and effort harvestin
g
a variet
y
of insects, principall
y
crickets,

g
rasshoppers, shore flies (Eph
y
dridae) (especiall
y
the pupae), caterpillars, and ants (adult
s
and pupae) though bees, wasps, stoneflies, aphids, lice, and beetles were also consumed on
an opportun
i
st
i
c
b
as
i
s. Some o
f
t
h
e
i
nsects were eaten raw t
h
oug
h
most were
b
a
k

e
d
or roaste
d
pr
i
or to
b
e
i
ng consume
d
;
f
urt
h
er,
l
arge quant
i
t
i
es, espec
i
a
ll
yo
f
grass
h

oppers an
d
cr
i
c
k
ets,
w
ere dried and
g
round to produce a flour that was stored for winter use (Sutton, 1988).
I
n parts of southeastern Australia the abori
g
inals would seasonall
yg
or
g
e themselves
on bogong moths (
A
grotis in
f
us
a
(
(
)
which estivate from December throu
g

h Februar
y
in vas
t
num
b
ers
i
n
hi
g
h
-a
l
t
i
tu
d
e caves an
d
roc
k
y outcrops
i
nt
h
e Sout
h
ern Ta
bl

e
l
an
d
s(F
i
gure 24.2).
Some tr
ib
es wou
ld
ma
k
e an annua
l
tre
k
over a cons
id
era
bl
e
di
stance (up to 200
k
m) to ta
k
e
a
d

vanta
g
eo
f
t
hi
s seasona
lf
oo
d
source, return
i
n
g
eac
hy
ear to t
h
e same area (F
l
oo
d
, 1980).
I
n some African countries (includin
g
Botswana, South Africa, Zaire, and Zimbabwe
)
t
here is a thrivin

g
trade in mopanie caterpillars (
G
onimbrasia belina), and when these ar
e
i
n season,
b
ee
f
sa
l
es may s
h
owas
i
gn
ifi
cant
d
ec
li
ne.As
i
m
il
ar pre
f
erence
f

or
i
nsects over
meat
i
ss
h
own
b
yt
h
eYup
k
a peop
l
eo
f
Co
l
om
bi
aan
d
Venezue
l
a (Ru
ddl
e, 1973). Insect
s
are a

l
so eaten
i
n man
y
As
i
an countr
i
es;
i
n
d
ee
d
,
gi
ant water
b
u
g
s(Let
h
oceru
s
in
d
icu
s
)

an
d
7
32
CHAPTER
24
B
FIGURE 24.2
.
(
A) T
h
e
b
ogong mot
h,
Agrotis in
f
usa;an
d
(B) est
i
vat
i
ng
b
ogong mot
h
s
f

orm
i
ng a sca
l
e
like
p
attern on a cave wa
ll
.A
b
or
igi
na
l
s
h
arveste
d
t
h
e mot
h
s
i
n vast num
b
ers
by di
s

l
o
dgi
n
g
t
h
em w
i
t
h
st
i
c
k
san
d
collecting them in nets or bark dishes held beneath. [A, photograph by J. Green. B, from D. F. Waterhouse, 1991,
Insects an
dh
umans
i
n Austra
li
a,
i
n:
Th
e Insects of Austra
l

i
a
,
2n
d
e
d
., Vo
l
. 1 (CSIRO, e
d
.), Me
lb
ourne Un
i
vers
i
ty
Press. B
y
perm
i
ss
i
on o
f
t
h
eD
i

v
i
s
i
on o
f
Entomo
l
o
gy
, CSIRO.]
7
33
I
N
S
E
C
T
SA
ND
HUM
A
NS
pupae of the silkmoth (
B
ombyx mori) are exported to Asian communit
y
food stores i
n

t
he United States from Thailand and South Korea, respectivel
y
. Mexico also used to shi
p
food insects to the United States, namel
y
ahuahutle (Mexican caviar—the e
gg
s of various
aquat
i
c Hem
i
ptera) an
d
maguey worms (caterp
ill
ars o
f
Ae
g
ia
l
e
h
esperiari
s
,
f

oun
d
on agave)
.
S
hi
pment o
f
a
h
ua
h
ut
l
e to Nort
h
Amer
i
ca no
l
onger occurs
b
ecause o
fl
a
k
epo
ll
ut
i

on, t
h
oug
h
i
t can st
ill b
e
f
oun
di
n man
y
mar
k
ets an
d
restaurants
i
nMex
i
co an
di
s exporte
d
to Europe
as bird and fish food. Ma
g
ue
y

worms are commonl
y
eaten in Mexico and are exported
as
g
ourmet food to North America, France and Japan (DeFoliart, 1992, 1999). However,
t
our
i
sts w
h
ov
i
s
i
tMex
i
co are pro
b
a
bl
y more
f
am
ili
ar w
i
t
h
anot

h
er caterp
ill
ar, t
h
ere
d
agav
e
w
orm
(
C
oma
d
ia re
d
ten
b
ac
hi
)
, seen
i
n
b
ott
l
es o
f

mezca
l
!
T
h
ere
h
as
b
een some
i
ncrease
i
n
i
nterest
i
nt
h
e potent
i
a
l
o
fi
nsects as
f
oo
d
,

i
nc
l
u
di
n
g
d
iscussion of the sub
j
ect at international conferences. However, most North Americans
and Europeans have not
y
et been educated to the deli
g
hts of insects, despite the efforts of
authors such as Taylor and Carter (1976), DeFoliart (1992, 1999), and Berenbaum (1995) to
i
ncrease t
h
e popu
l
ar
i
ty o
fi
nsects as
f
oo
d

.T
h
e western wor
ld
’s
bi
as aga
i
nst eat
i
ng
i
nsects
h
a
s
t
wo negat
i
ve
i
mpacts. F
i
rst,
i
t may
b
e seen as a m
i
sse

d
opportun
i
ty. Compare
d
to
li
vestoc
k
,
insects are much more efficient at convertin
g
plant material into animal material with hi
gh
nutritional value. With relativel
y
little research, industrial-scale mass production of foo
d
insects should be possible. Second, as less-developed areas of the world become increasingly
w
estern
i
ze
d
,t
h
e
i
r popu
l

at
i
ons may
b
e expecte
d
to eat
f
ewer
i
nsects. T
hi
s cou
ld l
ea
d
t
o
nutr
i
t
i
ona
l
pro
bl
ems
i
n areas w
h

ere t
h
e economy
i
sa
l
rea
d
y marg
i
na
l
(DeFo
li
art, 1999)
.
2
.5.
S
oil-Dwellin
g
and
S
caven
g
in
g
Insect
s
By t

h
e
i
r very
h
a
bi
tt
h
ema
j
or
i
ty o
f
so
il
-
d
we
lli
ng
i
nsects are
i
gnore
db
y
h
umans. On

l
y
th
ose t
h
at a
d
verse
l
ya
ff
ect our we
ll
-
b
e
i
ng,
f
or examp
l
e, term
i
tes, w
i
reworms, an
d
cutworms,
norma
lly

“mer
i
t” our attent
i
on. W
h
en p
l
ace
di
n perspect
i
ve,
h
owever,
i
t seems pro
b
a
bl
et
h
at
t
he dama
g
e done b
y
such pests is
g

reatl
y
outwei
g
hed b
y
the benefits that soil-dwellin
g
insect
s
as a
g
roup confer. The benefits include aeration, draina
g
e, and turnover of soil as a result of
b
urrow
i
ng act
i
v
i
ty. Many spec
i
es carry an
i
ma
l
an
d

p
l
ant mater
i
a
l
un
d
ergroun
df
or nest
i
ng
,
f
ee
di
ng, an
d
/or repro
d
uct
i
on, w
hi
c
hh
as
b
een compare

d
to p
l
oug
hi
ng
i
n a cover crop
.
Many
i
nsects,
i
nc
l
u
di
ng a
l
arge num
b
er o
f
so
il
-
d
we
lli
ng spec

i
es, are scavengers; t
h
at
is, the
y
feed on deca
y
in
g
animal or plant tissues, includin
g
dun
g
, and thus accelerate the
return of elements to food chains. In addition, throu
g
h their activit
y
the
y
ma
y
prevent use of
t
he decaying material by other, pest insects, for example, flies. Perhaps of special interes
t
are t
h
e

d
ung
b
eet
l
es (Scara
b
ae
id
ae), most spec
i
es o
f
w
hi
c
hb
ury p
i
eces o
ff
res
hd
ung
f
or
u
se as egg-
l
ay

i
ng s
i
tes (F
i
gure 24.3). Genera
ll
y, t
h
e
b
eet
l
es are su
ffi
c
i
ent
l
ya
b
un
d
ant t
h
at a
pat of fresh dun
g
ma
y

completel
y
disappear within a few hours, thus reducin
g
the numbe
r
of dun
g
-breedin
g
flies that can locate it. Furthermore, the chances of fl
y
e
gg
s or larvae
survivin
g
within the dun
g
are ver
y
low because the dun
g
is
g
round into a fine paste as th
e
b
eet
l

es or t
h
e
i
r
l
arvae
f
ee
d
.L
ik
ew
i
se, t
h
e surv
i
va
l
o
f
t
h
e eggs o
f
tapeworms, roun
d
worms,
etc., present

i
nt
h
e
d
ung pro
d
ucer,
i
s severe
l
yre
d
uce
db
yt
hi
s act
i
v
i
ty
.
I
n Australia there are an estimated 22 million cattle and 1
6
2 million sheep that collec-
t
ivel
y

produce 54 million tonnes of dun
g
(measured as dr
y
wei
g
ht) each
y
ear! The cattl
e
d
un
g
especiall
y
provides food and shelter for man
y
insects, includin
g
the larvae of two
fl
y pests, t
h
e
i
ntro
d
uce
db
u

ff
a
l
o
fl
y
(
Haemato
b
ia irritans exi
g
ua)
i
n
no
r
the
rn A
ust
r
alia
an
d
t
h
e nat
i
ve
b
us

hfl
y(
M
usca
v
etustissima)
i
n
s
out
h
eastern an
d
sout
hw
estern areas o
f
t
he
countr
y
. Furt
h
er,
b
ecause o
f
t
h
e

g
enera
lly d
r
y
c
li
mate, t
h
e
d
un
g
soon
d
r
i
es an
d
ma
y
rema
in
7
34
CHAPTER
24
F
I
GU

RE 24.3. (A) A dung beetle,
S
is
y
phus rubrus
,
with its ball of dung which is rolled away from the dung
pa
d
an
d
t
h
en
b
ur
i
e
d
.T
hi
s sout
h
ern A
f
r
i
can spec
i
es was

i
ntro
d
uce
di
nto Austra
li
a
i
n 1973; an
d
(B)
di
agrammat
i
c
sect
i
on t
h
rou
gh
nest o
f
t
h
e Austra
li
an nat
i

ve
d
un
gb
eet
le
Ont
h
op
h
agus compositus
,
w
hi
c
h
co
l
on
i
zes t
h
e
d
un
g
o
f
kangaroos, wallabies, and wombats. [A, photograph by J. Green. By permission of the Division of Entomology
,

C
SIRO. B,
f
rom G. F. Bornem
i
ssza, 1971, A new var
i
ant o
f
t
h
e paracopr
i
c nest
i
ng type
i
nt
h
e Austra
li
an
d
ung
b
eet
l
e
,
Ont

h
op
h
agus compositu
s
,
P
e
d
o
b
io
l
ogi
a
11
:1–10. B
y
perm
i
ss
i
on o
f
Gustav F
i
sc
h
er Ver
l

a
g
.
]
7
35
I
N
S
E
C
T
SA
ND
HUM
A
NS
u
nchan
g
ed for a considerable time so that the fiber and nutrients are unavailable to maintain
soil fertilit
y
and texture. Rank herba
g
e
g
rows around each dun
g
pat, and this is not normall

y
eaten b
y
cattle. Thus, at an
y
time, dun
g
pats render a si
g
nificant proportion (estimated at
a
b
out 20%) o
f
a
ll
pasture potent
i
a
ll
y unusa
bl
e (Water
h
ouse, 1974). A
l
t
h
oug
h

Austra
li
a
h
as
more t
h
an 320
i
n
di
genous spec
i
es o
fd
ung
b
eet
l
es, a
l
most a
ll
o
f
t
h
ese use on
l
yt

h
e
d
un
g
o
f
nat
i
ve marsup
i
a
l
s, espec
i
a
lly k
an
g
aroos, wa
ll
a
bi
es, an
d
wom
b
ats, an
d
,

f
urt
h
ermore, ar
e
restricted to forest and woodland habitats. Onl
y
a few species of the native Onthophagus
h
ave adapted to usin
g
cattle dun
g
(Waterhouse and Sands, 2001)
.
I
n 1963, it was decided to initiate a program of biological control of dung, and in
19
6
7, after extensive research, various species of tropical southern African dung beetles
w
ere re
l
ease
di
n nort
h
ern Austra
li
a. T

h
ese spec
i
es
h
a
db
een care
f
u
ll
yse
l
ecte
df
rom reg
i
on
s
climaticall
y
similar to northern Australia and because the
y
were known to be effective
processors of the dun
g
of lar
g
e native ruminants. The results were spectacular, the beetles
rapidly multiplied and spread over wide distances, while simultaneously achieving complete

or partial disposal of dung for much of the year (Waterhouse, 1974). Over the next 1
5
years
,
about
5
0 additional species of dung beetles, plus a few species of histerid beetles that pre
y
on fl
y
e
gg
s, larvae, and puparia, were imported not onl
y
from southern Africa but als
o
from southern Europe and Asia, each havin
g
features appropriate to a particular re
g
ion of
Australia. Of the 50-odd species released, 25 dung beetles and 3 histerids have establishe
d
b
ree
di
ng popu
l
at
i

ons
i
nt
h
e
fi
e
ld
,t
h
oug
h
num
b
ers (an
d
e
ff
ect
i
veness o
fd
ung process
i
ng)
may
b
e
hi
g

hl
yvar
i
e
d
accor
di
ng to t
h
e spec
i
es,
l
oca
li
ty, season, an
d
weat
h
er con
di
t
i
on
s
(Waterhouse and Sands, 2001). All of thespecies establishedin northern re
g
ions arecommo
n
in all except the winter months, and throu

g
h the summer almost complete dispersal of
d
un
g
occurs. Further, there is some evidence that such intense activit
y
results in a re
g
ional
suppress
i
on o
fb
u
ff
a
l
o
fl
y num
b
ers
.
I
nt
h
e coo
l
er sout

h
east an
d
sout
h
west o
f
Austra
li
at
h
e
i
ntro
d
uce
d
spec
i
es are most act
i
v
e
i
nt
h
e summer an
d
autumn mont
h

sw
h
en t
h
e
i
r
d
un
gdi
spersa
l
ma
y
su
b
stant
i
a
lly
re
d
uce
b
us
h
fly
abundance. However, their activit
y
is

g
enerall
y
low in winter and sprin
g
, the latter bein
g
t
he
p
eriod in southwestern Australia when massive
p
o
p
ulations of bush flies develo
p
(Doube
e
ta
l
., 1991). T
h
us,
i
n 1989, t
h
ree spr
i
ng-act
i

ve spec
i
es were
i
mporte
df
rom Spa
i
n; one o
f
th
ese
,
Bu
b
a
sb
i
s
on, esta
bli
s
h
e
di
tse
lf
qu
i
c

kl
yt
h
oug
h
popu
l
at
i
ons o
f
t
h
eot
h
er two spec
i
e
s
t
oo
kl
onger to
i
ncrease
b
ecause o
f
t
h

e
i
r comp
l
ex
b
ree
di
ng
b
e
h
av
i
or (Creag
h
, 1993).
I
n terms of dun
g
disposal, the Australian dun
g
beetle pro
j
ect has been a ma
j
or success
,
savin
g

farmers the costs of harrowin
g
, acceleratin
g
the release of nutrients into the soil,
and reducing the availability of fly breeding sites. No comprehensive study of the impact o
f
th
e
i
ntro
d
uce
db
eet
l
es on t
h
e pest
fl
y pro
bl
em
h
as
b
een un
d
erta
k

en. However, Water
h
ous
e
an
d
San
d
s (2001) prov
id
e examp
l
es to s
h
ow t
h
at t
h
e
b
eet
l
es may s
i
gn
ifi
cant
l
yre
d

uce
fl
y
populations at a local level, especiall
y
when rainfall, which prolon
g
s the beetles’ breedin
g
activit
y
, is favorable. A compoundin
g
factor in an
y
attempt to estimate the beetles’ impact is
t
he ease with which the flies are carried on wind currents from regions where they have bred
success
f
u
ll
y. T
hi
s ten
d
stomas
kl
oca
l

e
ff
ects o
fd
ung
b
eet
l
e act
i
v
i
ty on
fl
y num
b
ers. In a
ll
pro
b
a
bili
ty t
h
e
d
ung
b
eet
l

e system w
ill b
ecome
b
ut one component o
f
an
i
ntegrate
d
program
f
or
fly
popu
l
at
i
on mana
g
ement, w
i
t
h
ot
h
er strate
gi
es
b

e
i
n
g
use
d
w
h
en
fly
popu
l
at
i
ons pea
k
.
2
.6. Other Benefits of Insect
s
T
h
e
i
rre
l
at
i
ve
l

ys
i
mp
l
e
f
oo
d
an
d
ot
h
er requ
i
rements, s
h
ort generat
i
on t
i
me, an
dhi
g
h
f
ecun
di
t
y
ena

bl
e man
yi
nsects to
b
e reare
d
c
h
eap
ly
an
d
eas
ily
un
d
er
l
a
b
orator
y
con
di
t
i
ons
73
6

CHAPTER
24
and, consequentl
y
, make them valuable in teachin
g
and research. Even at the pre-colle
ge
l
evel, these attributes, plus their remarkable diversit
y
of form and habits, make insects a
n
i
m
p
ortant resource both in and outside the classroom (Matthew
s
et al.
, 1997). The fruit fl
y,
D
rosop
h
i
l
ame
l
ona
g

aste
r
wi
t
hi
ts array o
f
mutants,
i
s
f
am
ili
ar to a
ll
w
h
ota
k
eane
l
ementar
y
c
o
ll
ege genet
i
cs c
l

ass, t
h
oug
hi
t must a
l
so
b
e apprec
i
ate
d
t
h
at t
h
e
i
nsect cont
i
nues to
h
ave an
i
mportant role in advanced
g
enetic research. Studies on other insects have provided us with
m
uch of our basic knowled
g

e of animal and cell ph
y
siolo
gy
, particularl
y
in the areas of nu
-
trition, metabolism, endocrinolo
gy
, and neuromuscular ph
y
siolo
gy
. Investi
g
ations into th
e
popu
l
at
i
on
d
ynam
i
cs o
f
some pest
i

nsects, espec
i
a
ll
y
f
orest spec
i
es,
l
e
d
to t
h
e
f
ormu
l
at
i
on
o
f some important concepts in population ecology (Gillott, 198
5
).
W
i
t
h
t

h
e
d
eve
l
opment o
f
m
i
cro
bi
a
l
res
i
stance to man
y
ant
ibi
ot
i
cs, t
h
ere
h
as
b
een a
revival in the use of ma
gg

ot therap
y
, the use of fl
y
larvae to clean wounds and promot
e
healin
g
(Sherma
n
et al.
,
2000). Ma
gg
ot therap
y
has been used for centuries in some societie
s
an
d
pro
b
a
bl
y
d
eve
l
ope
d

as a resu
l
to
f
casua
l
o
b
servat
i
ons t
h
at t
h
e
l
arvae o
f
some my
i
as
i
s-
c
aus
i
ng
fli
es
h

a
db
ene
fi
c
i
a
l
e
ff
ects on
i
n
f
ecte
d
woun
d
s. My
i
as
i
s, t
h
e
i
n
f
estat
i

on o
f
an
i
ma
l
t
i
ssues (
li
v
i
n
g
or
d
ea
d
)
by
ma
gg
ots, appears to
h
ave evo
l
ve
di
n some D
i

pteran
f
am
ili
es t
h
at
w
ere ori
g
inall
y
sapropha
g
ous, that is, bred in carrion. Currentl
y
, it is mostl
y
seen in thre
e
f
amilies: Oestridae (all 150 species), Sarcopha
g
idae, and Calliphoridae (about 80 species
i
n tota
l
)(C
h
a

p
ter 9, Sect
i
on 3). However, most o
f
t
h
ese s
p
ec
i
es are unsu
i
ta
bl
e
f
or use
i
n
m
aggot t
h
erapy
b
ecause t
h
ey
f
ee

d
on
h
ea
l
t
h
yt
i
ssue, are
hi
g
hl
y
h
ost-spec
ifi
c, an
dh
av
e
o
t
h
er
di
sa
d
vanta
g

es. O
f
t
h
e 10 or so spec
i
es o
f
“me
di
c
i
na
l
ma
gg
ots,” t
h
e most common are
l
arvae of the
g
reenbottle fl
y
,
L
ucilia sericata. Curiousl
y
, in the United Kin
g

dom, continental
Europe, and New Zealand, this fl
y
isama
j
or sheep pest, causin
g
“strike,” which ma
y
be
f
ata
li
n
h
eavy
i
n
f
estat
i
ons (S
h
erman et a
l
., 2000).
M
any
i
nsects g

i
ve us p
l
easure t
h
roug
h
t
h
e
i
r aest
h
et
i
cva
l
ue. Because o
f
t
h
e
i
r
b
eauty,
c
erta
i
n groups, espec

i
a
ll
y
b
utter
fli
es, mot
h
s, an
db
eet
l
es, are somet
i
mes co
ll
ecte
d
as a
h
o
bb
y.
S
ome are embedded in clear materials from which
j
ewelr
y
, paperwei

g
hts, bookends, plac
e
m
ats, etc., are made. Others are simpl
y
used as models on which paintin
g
s and
j
ewelr
y
ar
e
based
.
3. Pest Insect
s
Since humans evolved, insects have fed on them, com
p
eted with them for food and
o
t
h
er resources, an
d
acte
d
as vectors o
f

m
i
croorgan
i
sms t
h
at cause
di
seases
i
nt
h
em or
in
t
h
e organ
i
sms t
h
at t
h
ey va
l
ue. However, as was note
di
nt
h
e Intro
d

uct
i
on, t
h
e
i
mpact o
f
suc
h
i
nsects increased considerabl
y
as the human population
g
rew and became more urbanized
.
Urbanization presented eas
y
opportunities for the dissemination of insect parasites on hu
-
m
ans and the diseases they carry. Large-scale and long-term cultivation of the same crop
ov
er
an
a
rea
f
ac

ili
tate
d
rap
id
popu
l
at
i
on
i
ncreases
i
n certa
i
np
l
ant-
f
ee
di
ng spec
i
es an
d
t
h
e
sprea
d

o
f
p
l
ant
di
seases. Mo
d
ern transportat
i
on, too, encourages t
h
e sprea
d
o
f
pest
i
nsect
s
and insect-borne diseases. Further, as described in Section 2.3, some of the attempts at pest
e
radication have backfired, resultin
g
in even
g
reater economic dama
g
e.
3

.1. Insects That Affect Humans Directl
y
A lar
g
e number of insect species ma
y
be external, or temporar
y
internal, parasites o
f
humans. Some of these are specific to humans, for example, the bod
y
louse
(
Pediculu
s
h
umanu
s
)
and
p
ubic louse
(
Phthirus pubi
s
)
, but most have a varied number of alternate
7
37

I
N
S
E
C
T
SA
ND
HUM
A
NS
F
IGURE 24.4. Summer transmission cycle of the western equine encephalomyelitis virus in the Central Valley of
Ca
lif
orn
i
a. T
h
e mos
q
u
i
to, Cu
l
ex tarsa
l
i
s
,i

s
th
epr
i
mar
y
vector o
f
t
h
ev
i
rus, an
dh
ouse
fi
nc
h
es an
dh
ouse sparrowst
h
e
p
rimar
y
amplif
y
in
g

hosts (hosts in which the virus multiplies). Secondar
y
(less important) amplif
y
in
g
hosts include
other passerine birds, chickens, and pheasants. Another transmission cycle involves blacktail jackrabbits, which
are somet
i
mes
bi
tten
by
C
. tarsa
l
is
,
an
d
A
e
d
es me
l
animan
.
Humans an
dh

orses, as we
ll
as
g
roun
d
squ
i
rre
l
s, tree
s
quirrels, and some other wild mammals become infected but do not contribute si
g
nificantl
y
to virus amplification
.
[
From J. L. Hardy, 1987, The ecology of western equine encephalomyelitis virus in the Central Valley of California,
194
5
–198
5,
A
m. J. Trop. Me
d
. Hyg
.
3

7
(
Supp
l
.):18S–32S. B
y
perm
i
ss
i
on o
f
t
h
e Amer
i
can Soc
i
et
y
o
f
Trop
i
ca
l
M
edicine and H
yg
iene.]

h
osts w
hi
c
h
compoun
d
st
h
e pro
bl
em o
f
t
h
e
i
r era
di
cat
i
on. W
i
t
h
rare except
i
ons,
f
or examp

l
e,
some m
y
iasis-causin
g
flies, insect parasites are not fatal to humans. In lar
g
e numbers, insect
parasites ma
yg
enerall
y
weaken their hosts, makin
g
them more susceptible to the attacks
of disease-causing organisms. Or the parasites, as a result of feeding, may cause irritatio
n
or sores w
hi
c
h
may t
h
en
b
ecome
i
n
f

ecte
d
.
But
b
y
f
ar t
h
e greatest
i
mportance o
fi
nsects t
h
at paras
i
t
i
ze
h
umans
i
st
h
e
i
rro
l
eas

v
e
ctors of patho
g
enic microor
g
anisms (includin
g
various “worms”) some well-known ex
-
amples of which are
g
iven in Table 24.1. The patho
g
en is picked up when a parasitic insect
feeds and ma
y
or ma
y
not
g
o throu
g
h specific sta
g
es of its life c
y
cle in the insect. Bacteri
a
an

d
v
i
ruses are
di
rect
l
y transm
i
tte
d
to new
h
osts, an
i
nsect serv
i
ng as a mec
h
an
i
ca
l
vector,
wh
ereas
f
or protozoa, tapeworms an
d
nemato

d
es, an
i
nsect serves as an
i
nterme
di
ate
h
ost
i
nw
hi
c
h
an essent
i
a
l
part o
f
t
h
e paras
i
tes’
lif
ec
y
c

l
e occurs (F
ig
ure 24.4). In t
h
e
l
atte
r
arran
g
ement the insect is known as a biolo
g
ical vector.
A patho
g
en ma
y
reside (and multipl
y
) in alternate vertebrate hosts that are immune to
or on
l
ym
ildl
y
i
n
f
ecte

db
y
i
t. For examp
l
e, t
h
e
b
acter
i
u
m
Pasteure
ll
a pestis,w
hi
c
h
cause
s
b
u
b
on
i
cp
l
ague (B
l

ac
k
Deat
h
),
i
sen
d
em
i
c
i
nw
ild
ro
d
ent popu
l
at
i
ons. However,
i
n
d
omest
i
c
rats an
dh
umans, to w

hi
c
hi
t
i
s transm
i
tte
dby
certa
i
n
fl
eas,
i
t
i
s
highly
pat
h
o
g
en
i
c. S
i
m
il
ar

ly
,
in South America,
y
ellow fever virus, transmitted b
y
mosquitoes, is found in monke
y
s
t
hou
g
h these are immune to it. Such alternate hosts are thus important reservoirs of disease
.
7
38
CHAPTER
24
TA
BLE 24
.
1
.
E
xam
p
les of Insects That Serve as Vectors for Diseases of Humans and
Domestic Animals
a
Insect vector

Pat
h
oge
n
Di
sease
Hos
t
D
ist
r
ibution
AN
O
PL
U
RA
P
e
d
iculu
s
humanu
s
R
ickettsia
p
rowazeki
i
Epidemic typhu

s
H
umans, rodent
s
World
w
ide
(b
o
dy l
ouse
)
(
r
i
c
k
etts
i
an
)
(Br
ill
s’
di
sease
)
Pasteurella tularensis
Tularemia
H

umans
,
ro
d
ent
s
N. Amer
i
ca, Euro
p
e, t
h
eOr
i
en
t
(
bacterium)
HEMIPTERA
R
h
o
d
niu
s
spp.
Trypanosoma cruz
i
Ch
a

g
as’
di
seas
e
Humans
,
ro
d
ent
s
S
. Amer
i
ca
,
Centra
l
Amer
i
ca
,
(
assassin bu
g
s
)
(p
rotozoan
)

M
exico
,
Texa
s
DIPTERA
P
hl
e
b
otomus
spp.
L
eis
h
mania
d
onovan
i
K
a
l
a-azar
H
uman
s
Me
di
terranean re
gi

on, As
i
a, S. Amer
i
c
a
(
sand flies
)
(p
rotozoan)
(
Dumdum fever
)
L
.tro
p
ica
O
riental sore
Hu
m
a
n
s
Africa, Asia, S. Americ
a
L.
b
ra

z
i
l
iensi
s
Espun
dia
Human
s
S
. Amer
i
ca, Centra
l
Amer
i
ca
,
N
.A
f
r
i
ca
,
sout
h
ern As
i
a

(
virus
)
Pappataci fever
Hu
m
a
n
s
Mediterranean region, India, Sri Lanka
(San
dfl
y
f
ever)
Anop
h
e
l
e
s
spp.
Pl
asmo
d
ium vivax
Ma
l
ar
ia

Human
s
W
or
ld
w
id
e
i
n tro
pi
ca
l
,su
b
tro
pi
ca
l
,
(
mos
q
uitoes)
(p
rotozoan)
and temperate re
g
ion
s

P.
m
ala
r
iae
M
a
l
a
ri
a
Hu
m
a
n
s
P.
fa
l
ciparum
Ma
l
ar
ia
Humans
Ae
d
e
s
spp.

(
virus
)
Y
ello
w
fe
v
e
r
Humans, monke
y
s,
American and African tro
p
ic
s
(mosquitoes)
rode
n
ts
and subtropic
s
(
v
i
rus
)
Dengue
Human

s
W
or
ld
w
id
e
i
n trop
i
cs an
d
su
b
trop
i
cs
(
v
i
rus
)
Ence
ph
a
li
t
i
s
Humans

,h
orses
N. Amer
i
ca, S. Amer
i
ca, Euro
p
e, As
ia
W
ucheria bancro
f
ti
Fil
a
ri
as
i
s
Hu
m
a
n
s
W
orldwide in tropics and subtropic
s
(
nemato

d
e)
(
E
l
ep
h
ant
i
as
i
s
)
C
u
l
e
x
spp.
(
v
i
rus
)
Den
g
ue
Humans
W
or

ld
w
id
e
i
n tro
pi
cs an
d
su
b
tro
pi
c
s
(mos
q
uitoes)
(
virus
)
Encephaliti
s
Humans, horses
N
. America, S. America, Europe, Asi
a
W
u
c

h
eria
b
ancrofti
F
il
ar
i
as
is
Humans
Worldwide in tropics and subtropics
(
nematode
)
(
Ele
p
hantiasis
)
T
abanu
s
s
pp.
Bacillu
s
anthraci
s
An

t
hr
a
x
Humans, other animal
s
W
orld
w
id
e
(
h
orse
fli
es
)
(
b
acter
i
um
)
7
39
I
N
S
E
C

T
SA
ND
HUM
A
NS
Chr
y
sops
s
pp
.
Pa
s
teurella tularen
s
i
s
Tu
l
a
r
e
mi
a
H
umans, rodents
N
. America, Europe, the Orient
(d

eer
fli
es
)
(b
acter
i
um
)
L
oa loa
Lo
i
as
i
s
Hu
m
a
n
s
A
fric
a
(nematode)
(Calabar swelling)
Gl
ossina
spp
.

T
rypanosoma
S
l
eep
i
n
g
s
i
c
k
nes
s
Humans, ot
h
er an
i
ma
l
sE
q
uator
i
a
l
A
f
r
i

ca
(
tsetse flies
)
rho
d
e
s
ien
s
e
(
protozoan
)
T
.
g
am
b
iense
S
l
eep
i
n
g
s
i
c
k

ness
Humans, ot
h
er an
i
ma
l
sE
q
uator
i
a
l
A
f
r
i
ca
T.
b
r
ucei
N
a
g
an
a
C
attle, wild un
g

ulates Equatorial Afric
a
S
IPH
O
NAPTER
A
X
enopsy
ll
ac
h
eopsis
Pasteure
ll
a pestis
B
u
b
on
i
cp
l
a
g
ue
Humans
,
ro
d

ents
W
or
ld
w
ide
(
oriental rat flea
)
(
bacterium
)
(
Black death
)
X
enops
y
lla spp
.
R
ickettsia t
y
ph
i
E
ndemic (murine
)
Humans, rodents
W

orld
w
id
e
(
r
i
c
k
etts
i
an
)
ty
p
h
u
s
X
enops
y
lla cheopsis
H
y
menolepis nan
a
T
a
p
ewor

m
Hu
m
a
n
s
E
uro
p
e and N. America
(cestode)
H.
d
iminut
a
T
a
p
ewor
m
H
umans
Wor
ld
w
ide
(
cestode
)
N

osopsyllus
f
asciatus Pasteurella pestis
B
ubonic plague
Humans, rodents
W
orld
w
id
e
(
nort
h
ern rat
fl
ea
)
(b
acter
i
um
)
(
B
l
ac
kd
eat
h)

Rickettsia t
y
phi
E
ndemic
(
murine
)
Humans
,
rodents
W
orld
w
id
e
(rickettsian)
t
yphu
s
Hymeno
l
epis
d
iminut
a
T
a
p
ewor

m
H
umans
Wor
ld
w
ide
(
cestode
)
Ctenocephalides canis Dip
y
lidium caninum
T
apewor
m
H
umans, dogs, cats
World
w
id
e
(d
o
gfl
ea)
(
cesto
d
e

)
H
y
menolepis nan
a
T
a
p
ewor
m
Hu
m
a
n
s
E
uro
p
e, N. America
(cestode)
Pu
l
ex irritan
s
Hymeno
l
epis nan
a
T
a

p
ewor
m
H
umans
E
uro
p
e, N. Amer
i
ca
(
human flea
)
(
cestode
)
a
D
ata
f
rom var
i
ous sources
.
7
40
CHAPTER
24
T

ransmission of human disease-causing microorganisms is not, however, entirely the
TT
domain of parasitic insects. Man
y
insects, especiall
y
flies, ma
y
act as mechanical vectors
,
c
ontaminatin
g
human food as the
y
rest or defecate on it, with patho
g
ens picked up dur-
i
ng contact w
i
t
hf
eces or ot
h
er organ
i
c waste. Examp
l
es o

f
suc
hi
nsects an
d
t
h
e
di
sease
s
transm
i
tte
db
yt
h
em are
li
ste
di
nTa
bl
e 24.1.
At
hi
r
d
cate
g

or
y
o
fi
nsects t
h
at
di
rect
ly
a
ff
ect
h
umans
i
nc
l
u
d
es t
h
ose t
h
at ma
ybi
te
o
r stin
g

when accidental contact is made with them, for example, bees, wasps, ants, some
c
aterpillars (with poisonous hairs on their dorsal surface), and blister beetles. Normall
y
,th
e
eff
ect o
f
t
h
e
bi
te or st
i
ng
i
s temporary an
d
not
hi
ng more t
h
an s
ki
n
i
rr
i
tat

i
on, swe
lli
ng, or
bli
ster
f
ormat
i
on. Bee st
i
ngs,
h
owever, may cause anap
h
y
l
ax
i
sor
d
eat
hi
n some sens
i
t
i
v
e
i

n
di
v
id
ua
l
s.
3
.2. Pests of Domesticated Animal
s
A range o
fi
nsect paras
i
tes may cause econom
i
ca
ll
y
i
mportant
l
eve
l
so
fd
amage to
d
omest
i

can
i
ma
l
s. T
h
ema
j
or
i
ty o
f
t
h
ese paras
i
tes are externa
l
an
di
nc
l
u
d
e
bl
oo
d
suc
ki

n
g
flies (e.
g
., mosquitoes, horse flies, deer flies, black flies, and stable flies), bitin
g
and suckin
g
l
ice, and fleas. Other parasites are internal for part of their life histor
y
, for example, bot,
w
arble, and screwworm flies, which as larvae live in the gut (horse bot), under the skin
(
war
bl
ean
d
screwworm o
f
catt
l
e), or
i
n
h
ea
d
s

i
nuses (s
h
eep
b
ot). Ot
h
er examp
l
es are g
i
ven
i
nt
h
ec
h
apters t
h
at
d
ea
l
w
i
t
h
t
h
eor

d
ers o
fi
nsects. In a
ddi
t
i
on to
i
nsects, ot
h
er art
h
ropo
d
s are
also important livestock pests, especiall
y
various mites and ticks. Kun
z
et al.
(
in Pimentel,
1
991, Vol. 1) estimated that direct losses caused b
y
insect and tick pests of livestock wer
e
almost
$

3 billion each
y
ear in the United States. Insecticide treatment is routine for som
e
pests, an
di
nt
h
ea
b
sence o
f
treatment,
l
osses cause
db
yt
h
ese pests (e.g., catt
l
e gru
b
s,
Hy
po
d
erma
b
ovis an
d

H.
l
ineatu
m
)m
i
g
h
t
b
easmuc
h
as ten t
i
mes greater. In
di
rect
l
osses
suc
h
as poor
b
ree
di
n
g
per
f
ormance

by b
u
ll
s, re
d
uce
d
concept
i
on rate
by
cows, an
dl
a
b
or
c
osts of treatin
g
livestock are not included in the above estimate
.
Generall
y
the effect of such parasites is to cause a reduction in the health of the infecte
d
an
i
ma
l
. In turn, t

hi
s resu
l
ts
i
na
l
oss o
f
qua
li
ty an
d
/or quant
i
ty o
f
meat, woo
l
,
hid
e, m
ilk
, etc.,
pro
d
uce
d
.W
h

en severe
l
y
i
n
f
ecte
db
y paras
i
tes, an an
i
ma
l
may eventua
ll
y
di
e. In a
ddi
t
i
on to
t
h
e
i
rown
di
rect e

ff
ect on t
h
e
h
ost, some paras
i
tes are vectors o
fli
vestoc
kdi
seases, examp
l
es
o
f which are included in Table 24.1
.
3
.3. Pests of Cultivated Plants
D
amage to crops an
d
ot
h
er cu
l
t
i
vate
d

p
l
ants
b
y
i
nsects
i
s enormous;
i
nt
h
eUn
i
te
d
S
tates alone losses in potential production are estimated at 13% and have a value of abou
t
US
$
30 billion annuall
y
, despite the application of more than 100,000 tonnes of insecti-
c
ide. Remarkabl
y
, about three quarters of the insecticide used is applied to 5% of the total
agr
i

cu
l
tura
ll
an
d
, espec
i
a
ll
yt
h
at grow
i
ng row crops suc
h
as cotton, corn, an
d
soy
b
ean (P
i
-
m
ente
l
et a
l.
,in
Pi

mente
l
, 1991, Vo
l
. 1). Damage
i
s cause
d
e
i
t
h
er
di
rect
l
y
b
y
i
nsects a
s
t
h
e
yf
ee
d
(
by

c
h
ew
i
n
g
or suc
ki
n
g
)orov
i
pos
i
t, or
by
v
i
ra
l
,
b
acter
i
a
l
,or
f
un
g

a
ldi
seases
,
f
or which insects serve as vectors. Especiall
y
important as “direct dama
g
ers” of plants are
O
rtho
p
tera, Le
p
ido
p
tera, Coleo
p
tera, and Hemi
p
tera (see the cha
p
ters that deal with these
o
r
d
ers
f
or s

p
ec
ifi
c exam
pl
es o
f
suc
hp
ests). Severa
lh
un
d
re
ddi
seases o
fpl
ants are
k
nown t
o
b
e transm
i
tte
db
y
i
nsects (
f

or examp
l
es see Ta
bl
e 24.2)
i
nc
l
u
di
ng a
b
out 300 t
h
at are cause
d
by
v
i
ruses (Eastop, 1977). Espec
i
a
lly i
mportant
i
n
di
sease transm
i
ss

i
on are Hem
i
ptera,
7
41
I
N
S
E
C
T
SA
ND
HUM
A
NS
TABLE 24.2. Examp
l
es o
f
P
l
ant D
i
seases Transm
i
tte
db
y Insects

a
Di
sease Im
p
ortant
h
ost
s
V
ectors
Di
str
ib
ut
i
o
n
V
iruses Alfalfa mosaic Alfalfa, tobacco,
p
otato
,
beans, peas, celery
,
zi
nn
i
a,
p
etun

ia
A
p
hids (at least 16 s
pp
.
)
incl
.
Ac
y
rthosiphon
p
rimu
l
ae,A.so
l
ani, Ap
h
is
c
raccivora, A.
f
abae, A
.
g
oss
y
pii, Macrosiphu
m

e
up
h
or
b
iae, M. pisi, Myzu
s
o
rnatus, M. pers
i
cae, M
.
v
iola
e
W
orld
w
id
e
Barle
yy
ellow
dw
ar
f
Barle
y
, oat, wheat, r
y

e,
wild and tame grasse
s
Numerous a
p
hids incl
.
Macrosiphum
g
ranarium
,
M. miscant
h
i, Myzu
s
c
ircum
fl
exus
,
R
ho
p
alosi
p
hum
p
adi, R.
mai
d

i
s
N
orth America
,
A
ustralia, Denmark
,
Ho
ll
an
d,
U
K
Bean commo
n
mosa
ic
Bean
s
Ap
hid
s (at
l
east 11 spp.
)
esp
.
A
p

h
is rumicis
,
Macrosiphum pisi, M.
g
e
i
W
or
ld
w
ide
Beet yellows Sugarbeet, spinach Aphids esp
.
A
phis
f
aba
e
,
M
y
zus persicae
W
herever sugarbee
t
i
s grow
n
C

auliflo
w
e
r
mosa
ic
C
auliflower, cabbage,
Chi
nese ca
bb
a
g
e
Aphids esp
.
Brevicor
y
n
e
b
rassicae, R
h
opa
l
osip
h
um
p
seudobrassicae, M

y
zus
p
ersica
e
E
urope, U
S
A,
N
ew Zea
l
an
d
Dahlia mosaic Dahlia, zinnia,
c
a
l
en
d
u
l
a
Aphids esp
.
My
zus
p
ersica
e

,
A
p
h
is fa
b
ae, A.
gossyp
ii
,
M
acrosip
h
um gei
,
M
y
zus convolvul
i
W
here
v
er dahlias ar
e
grow
n
Lettuce
m
osaic
L

ettuce, sweet
p
ea
,
g
ar
d
en pea, en
di
ve,
a
ster
,
z
i
nn
i
a
A
p
hids es
p
.
My
zus
p
ersica
e
,
A

p
h
is
g
oss
y
pii
,
Macrosip
h
um eup
h
or
b
ia
e
E
uro
p
e, USA (es
p
.
Ca
lif
orn
i
a),
N
ew Zea
l

an
d
Pea mosa
i
c Gar
d
en
p
ea, sweet
p
ea
,
b
roadbean, lu
p
in
,
clo
v
ers
A
phid
s
:
A
cyrt
h
osip
h
o

n
pi
sum, M
y
zus pers
i
cae
,
Aphis
f
abae, A. rumicis
E
uro
p
e, U
S
A,
N
ew Zealand
,
A
ustralia, Japan
Potato virus Y Potato, tobacco, tomato,
p
etun
i
a,
d
a
hli

a
Aphids esp.
My
zus
p
ersicae, M. certus, M
.
ornatus, Macrosip
h
u
m
e
u
p
horbiae
U
K, France, U
SA
S
oybea
n
m
osaic
S
oybea
n
Aphids incl
.
M
y

zus
p
ersicae, Macrosi
ph
um
p
is
i
W
herever soybean is
grow
n
S
ugarcane
mosa
ic
S
ugarcane, com,
sor
gh
um, ot
h
er tame
a
nd wild
g
rasse
s
Numerous ap
hid

s
i
nc
l.
R
h
opa
l
osip
h
um mai
d
is,
Aphis
g
oss
y
pii, Schizaphi
s
g
raminum, M
y
zus persica
e
Wh
erever sugarcane
i
s
g
row

n
To
m
ato
spotte
d
w
ilt
Tomato, tobacco
,
d
a
hli
a, p
i
neapp
l
e
Thrips
:
Thri
p
s tabaci,
Fr
ankliniella schultzeri, F.
rr
f
usca, F. occidentalis
A
frica, Asia,

A
ustra
li
a, Europe,
N
orth and
S
outh
A
m
e
ri
ca
(
C
ontinue
d
)
7
42
CHAPTER
24
TA
BLE 24.2.
(
C
ontinue
d
)
Disease Im

p
ortant hosts
V
ectors Di
st
ri
but
i
o
n
Turn
i
pye
ll
o
w
mosa
ic
Turn
i
p, cau
lifl
ower
,
Chi
nese ca
bb
a
g
e

,
kohlrabi, cabba
g
e
,
Br
occo
l
i
Fl
ea
b
eet
l
es (P
h
y
ll
otret
a
spp
.); Mustar
db
eet
l
e
(
Phae
d
on cochlearia

e
);
Grasshoppers (Leptoph
y
e
s
p
unctatissima, C
h
ort
h
ippus
bicolor); Earwi
g(
For
fi
cul
a
au
r
icula
r
ia
)
U
K,
G
ermany,
P
ortu

g
a
l
, Nort
h
A
m
e
ri
ca
M
ycoplasmas Aster yellows Aster, celery, carrot
,
squas
h
, cucum
b
er,
w
h
eat,
b
ar
l
e
y
N
umerous leafhoppers incl
.
G

yponana
h
asta
,
Scap
h
ytopius acutus, S.
i
rroratus
,
Macrosteles
quadrilineatus,
P
a
r
aphlepsius apertinus,
rr
Te
xananus
e
e
(several s
p
ecies
)
World
w
ide
C
l

over
p
hyllod
y
Most clo
v
er
s
Leafho
pp
ers incl
.
Ap
hrode
s
albi
f
rons, Macrostele
s
cristata. M. qua
d
ri
l
ineatus
,
M. viri
d
igriseus. Eusce
l
i

s
l
ineolatus, E. plebe
j
a
U
SA
,
U
K
C
orn stunt
C
orn
L
eafhoppers esp
.
Dalbulu
s
e
l
imatus. D. mai
d
is
.
G
ramine
ll
a nigrifron
s

N
orth and
C
entra
l
A
m
e
r
ica
B
acter
i
a Stewart’
s
b
acterial
w
il
t
C
or
n
C
orn
fl
ea
b
eet
le

(
C
haetocneme
p
ulicara
)
;
toothed flea beetle
(
C
.
d
enticu
l
at
a
)
U
SA
C
ucur
bi
tw
il
t Cucum
b
er
,
mus
k

me
l
on Cucum
b
er
b
eet
l
e
s
(
Diabrotica vittata, D
.
duodecim
p
unctata)
US
A, Europe
,
South Africa, Ja
p
a
n
Potato
bl
ac
kl
e
g
Potato

Seedcorn maggot (H
y
lem
y
a
ci
l
icrur
a
),
H. tric
h
o
d
acty
l
a
N
orth America
F
i
re
bli
g
h
t 90 spp. o
f
orc
h
ar

d
tree
s
a
n
d
ornamenta
l
s, es
p
.
app
le,
p
ear,
q
uinc
e
Wid
e range o
fi
nsec
t
vectors, es
p
.
b
ees, was
p
s,

flies, Ants, a
p
hids
N
ort
h
Amer
i
ca
,
E
uro
pe
F
un
g
i Dutch elm
d
i
sease
Elm Elm bark beetles, es
p
.
Scol
y
tus multistriatus
,
S. sco
l
ytus, Hy

l
urgopinu
s
r
u
fi
pe
s
A
sia, Euro
p
e, Nort
h
A
m
e
ri
ca
Er
g
ot Cereals and othe
r
g
rasse
s
About 40 s
pp
. of insect
s
Esp.flies, beetles, aphids

World
w
ide
a
D
ata from
v
arious sources.
part
i
cu
l
ar
l
y
l
ea
fh
oppers an
d
ap
hid
s. T
h
ree aspects o
f
t
h
e
b

e
h
av
i
or o
f
t
h
ese
i
nsects
f
ac
ili
tate
t
h
e
i
rro
l
eas
di
sease vectors: (1) t
h
e
y
ma
k
e

b
r
i
e
fb
ut
f
requent pro
b
es w
i
t
h
t
h
e
i
r mout
h
parts
i
nto host plants; (2) as the population densit
y
reaches a critical level, win
g
ed mi
g
rator
y
i

ndividuals are produced; and (3) in many species, winged females deposit a few progeny
o
n eac
h
o
f
many p
l
ants,
f
rom w
hi
c
h
new co
l
on
i
es
d
eve
l
op. On t
h
e
b
as
i
so
f

t
h
e
i
r met
h
o
d
o
f transmission and viabilit
y
(persistence in the vector), viruses ma
y
be arran
g
ed in three
7
43
I
N
S
E
C
T
SA
ND
HUM
A
NS
cate

g
ories. The non-persistent (st
y
let-borne) viruses are those believed to be transmitte
d
as contaminants of the mouthparts. Such viruses remain infective in a vector for onl
y
a
ver
y
short time, usuall
y
an hour or less. Semipersistent viruses are carried in the ante-
r
i
or reg
i
ons o
f
t
h
e gut o
f
a vector, w
h
ere t
h
ey may mu
l
t

i
p
l
y to a certa
i
n extent. Vectors
d
o not norma
ll
y rema
i
n
i
n
f
ect
i
ve a
f
teramo
l
t, presuma
bl
y
b
ecause t
h
ev
i
ruses are

l
os
t
w
hen the fore
g
ut intima is shed. Persistent (circulative or circulative-propa
g
ative) viruse
s
are those that, when acquired b
y
a vector, pass throu
g
h the mid
g
ut wall to the salivar
y
g
lands from where the
y
can infect new hosts. Such viruses ma
y
multipl
y
within tissues of
a
v
e
ctor, w

hi
c
h
reta
i
ns t
h
ea
bili
ty to transm
i
tt
h
ev
i
rus
f
or a cons
id
era
bl
et
i
me,
i
n som
e
i
nstances
f

or t
h
e rest o
fi
ts
lif
e. Pers
i
stent v
i
ruses
,i
n contrast to t
h
ose
i
nt
h
e
fi
rst two cate
-
g
or
i
es, ma
yb
equ
i
te spec

ifi
cw
i
t
h
respect to t
h
e vectors capa
bl
eo
f
transm
i
tt
i
n
g
t
h
em (Hu
ll
,
2002).
3.4. Insect Pests of Stored Product
s
A
l
most an
y
store

d
mater
i
a
l
,w
h
et
h
er o
f
p
l
ant or an
i
ma
l
or
igi
n, ma
yb
esu
bj
ect to attac
k
by
insects, especiall
y
species of Coleoptera (larvae and adults) and Lepidoptera (larva
e

onl
y
). Amon
g
the products that are frequentl
y
dama
g
ed are
g
rains and their derivatives,
b
eans, peas, nuts,
f
ru
i
t, meat,
d
a
i
ry pro
d
ucts,
l
eat
h
er, an
d
woo
l

en goo
d
s. In a
ddi
t
i
on, woo
d
an
di
ts pro
d
ucts may
b
e spo
il
e
db
y term
i
tes or ants. Aga
i
n, rea
d
ers s
h
ou
ld
re
f

er to t
he
appropr
i
ate c
h
apters
d
escr
ibi
n
g
t
h
ese
g
roups
f
or spec
ifi
c examp
l
es.
Estimates of the worldwide postharvest losses of foodstuffs (especiall
y
stored
g
rains
)
ma

y
be as hi
g
h as 20%, of which about one-half is attributable to insects and the rest to
microorganisms, rodents, and birds. Even in well-developed countries such as the Unite
d
States, Cana
d
a, an
d
Austra
li
aw
h
ere storage con
di
t
i
ons are more a
d
equate an
d
pest
i
c
id
e
t
reatment is available, losses of
5

% to 10% are estimated for stored grains. Given a world-
w
ide estimate for the production of wheat, coarse
g
rains, and rice as about 1.
5
billio
n
t
onnes in 1981–1982, perhaps as much as 150 million tons ma
y
have been lost as a re-
sult of insect damage. The nature of the damage caused by stored products pests varies
.
G
ra
i
nan
d
ot
h
er see
d
pests not on
l
y eat econom
i
ca
ll
yva

l
ua
bl
e quant
i
t
i
es o
ff
oo
d
,
b
ut cause
spo
il
age
b
y contam
i
nat
i
on w
i
t
hf
eces, o
d
ors, we
bbi

ng, corpses, an
d
s
h
e
d
s
ki
ns, an
db
y
creat
i
n
gh
eat an
d
mo
i
sture
d
ama
g
et
h
at perm
i
ts t
h
e

g
rowt
h
o
f
m
i
croor
g
an
i
sms (W
ilb
u
r
and Mills, in Pfadt, 1985). Pests of household
g
oods such as clothin
g
and furniture prin-
cipall
y
cause dama
g
eb
y
spoila
g
e, for example, b
y

tunnelin
g
, defecatin
g
, and creatin
g
o
d
ors.
4. Pest
C
ontrol
As w
ill b
e apparent
f
rom w
h
at was sa
id
a
b
ove, pests are organ
i
sms t
h
at
d
amage, to a
n

econom
i
ca
ll
ys
i
gn
ifi
cant extent,
h
umans or t
h
e
i
r possess
i
ons, or t
h
at
i
n some ot
h
er way ar
e
a source o
f
anno
y
ance to
h

umans. Imp
li
c
i
t
i
nt
h
ea
b
ove
d
escr
i
pt
i
on are va
l
ue
j
u
dg
ments t
h
a
t
ma
y
var
y

accordin
g
to who is makin
g
them, as well as where and when the
y
are bein
g
made
.
N
evertheless, in a given set of circumstances, there will be an economic injury (annoyance)
th
res
h
o
ld
, measure
di
n terms o
f
a spec
i
es’ popu
l
at
i
on
d
ens

i
ty, a
b
ove w
hi
c
hi
t
i
s
d
es
i
ra
bl
e
(pro
fi
ta
bl
e) to ta
k
e contro
l
measures t
h
at w
ill
re
d

uce t
h
e spec
i
es’
d
ens
i
ty.Ast
h
e marg
i
n
b
etween econom
i
c
i
n
j
ur
y
t
h
res
h
o
ld
an
d

actua
l
popu
l
at
i
on
d
ens
i
t
y
w
id
ens, t
h
e
d
es
i
ra
bili
t
y
7
44
CHAPTER
24
TA
BLE 24.

3
.
P
rincipal Control Methods in Relation to Ecolo
g
ical Strate
g
ies of Pests
a
r
pests Intermediate pests K pests
Contro
l
met
h
o
d
:
P
est
i
c
id
es
B
iological contro
l
Cu
l
tura

l
contro
l
G
enet
i
c contro
l
E
xamples (with
S
chistocerca
g
re
g
ari
a
(
Most deciduous forest
Or
y
ctes rhinoceros
i
mportant (
d
esert
l
ocust) pests,
f
ru

i
t pests, an
d
(r
hi
noceros
b
eet
l
e)
f
eatures): Fecun
di
t
y
/
X
=
400 e
gg
s some ve
g
eta
bl
e pests) Fecun
di
t
y
/
X

=
5
0e
gg
s
G
eneration time
=
G
eneration tim
e
=
3
–4
1
–2 m
o
n
ths
mo
n
ths
M
ig
rator
y
,
d
e
f

o
li
ate
s
Fee
d
sonap
i
ca
lg
row
i
n
g
many crops
p
oints of coconuts
A
phis
f
aba
e
G
lossina spp.
(
bl
ac
kb
ean ap
hid

)
(
tsetse
fl
y)
Fecun
di
t
y
/
X
=
1
00 e
gg
s Fecun
di
t
y
/
X
=
10 e
gg
s
G
eneration time
=
G
eneration tim

e
=
2
–
3
1
–2
w
eeks
mo
n
t
h
s
Fee
d
sonw
id
e ran
g
e
F
ee
d
s on narrow ran
g
eo
f
o
f

p
lant
s
h
ost
s
M
u
s
ca
d
ome
s
tica C
y
dia pomonell
a
(
h
ouse
fl
y)
(
co
dli
ng mot
h
)
Fecun
di

t
y
/
X
=
5
00 e
gg
s Fecun
di
t
y
/
X
=
4
0e
gg
s
G
eneration time
=
G
eneration tim
e
=
2
–
6
2

–
3w
eeks
mo
n
t
h
s
Fee
d
sonor
g
an
ic
Larvae
f
ee
d
on app
l
ean
d
w
as
t
e
s
ome other fruit
s
Ag

rotis ipsilo
n
Melopha
g
us ovinu
s
(
bl
ac
k
cutworm)
(
s
h
eep
k
e
d
)
Fecun
di
t
y
/
X
=
15
00 e
gg
s Fecun

di
t
y
/
X
=
1
5
e
gg
s
G
eneration time
=
1–1.
5
G
eneration tim
e
=
1
–2
m
o
n
t
h
s
mo
n

t
h
s
Fee
d
sonsee
dli
n
g
so
f
E
xterna
l
paras
i
te o
f
s
h
ee
p
mos
t
cro
ps
a
D
ata from Conway (1976) and Southwood (1977).
(

profitabilit
y
) of control increases. Pest control is, then, essentiall
y
a sociolo
g
ical problem—
a matter of economics, politics, and ps
y
cholo
gy
.
A range o
f
met
h
o
d
s
i
sava
il
a
bl
e
f
or t
h
e contro
l

o
fi
nsect pests. Eac
h
o
f
t
h
ese met
h
o
d
s
h
as
i
ts a
d
vanta
g
es an
ddi
sa
d
vanta
g
es an
d
t
h

ese must
b
e
b
a
l
ance
d
a
g
a
i
nst eac
h
ot
h
er
in
determinin
g
which (combination of) method(s) is most appropriate in a
g
iven instance
.
Some of these methods are s
p
ectacular but short-term and will be a
pp
ro
p

riate, for exam
p
le,
wh
ere mass
i
ve out
b
rea
k
so
f
pests are re
l
at
i
ve
l
ysu
dd
en, yet unpre
di
cta
bl
ean
d
temporary
.
O
t

h
ers are more s
l
ow
ly
act
i
n
gb
ut re
l
at
i
ve
ly
permanent
i
ne
ff
ect, an
d
ma
yb
e use
df
or pest
s
that are more or less permanent but whose populations are relativel
y
stable.

Conway (1976) and Southwood (1977) proposed that pests can be arranged in a spec-
trum accor
di
ng to t
h
e
i
r “eco
l
og
i
ca
l
strateg
i
es” an
d
t
h
at t
h
epr
i
nc
i
pa
l
(
b
est) met

h
o
d
o
f
contro
l
i
s
b
ase
d
on t
h
e
i
r pos
i
t
i
on
i
nt
h
e spectrum (Ta
bl
e 24.3). At e
i
t
h

er en
d
o
f
t
h
e spectrum are
t
h
eso
-
ca
ll
ed “
r
p
ests” and “
K
p
ests,” with the “intermediate
p
ests” in between
.
7
45
I
N
S
E
C

T
SA
ND
HUM
A
NS
The
r
p
ests are characterized b
y
their potentiall
y
hi
g
h rates of population increas
e
(resultin
g
from the hi
g
h fecundit
y
and short
g
eneration time), well-developed powers of
d
ispersal (mi
g
ration) and abilit

y
to locate new food sources, and rather
g
eneral food pref-
erences. T
h
ese
f
eatures ena
bl
e
r
pests to co
l
on
i
ze temporar
il
ysu
i
ta
bl
e
h
a
bi
tats,
i
nw
hi

c
h
th
ere
i
s typ
i
ca
ll
y
li
tt
l
e
i
nterspec
ifi
c compet
i
t
i
on
f
or t
h
e resources ava
il
a
bl
e. Because

r
pests
ma
y
occur
i
n suc
hl
ar
g
e
b
ut unpre
di
cta
bl
e num
b
ers an
d
rap
idly
c
h
an
g
et
h
e
i

r
l
ocat
i
on, pre
d
a
-
t
ors (of which there ma
y
be man
y
) have relativel
y
little effect on their population. Further,
althou
g
h like other or
g
anism
s
r
p
ests are sub
j
ect to disease, the latter is slow to take ef-
f
ect,
b

yw
hi
c
h
t
i
me s
i
gn
ifi
cant
d
amage may
h
ave
b
een
d
one. F
i
na
ll
y,
b
ecause o
f
t
h
e
i

r
hi
g
h
repro
d
uct
i
ve potent
i
a
l,
r
pests are a
bl
etoto
l
erate mass morta
li
ty an
d
rap
idl
y regenerate
th
e
i
ror
i
g

i
na
ld
ens
i
ty. Hence,
bi
o
l
og
i
ca
l
contro
l
,w
hi
c
hi
sare
l
at
i
ve
l
ys
l
ow
b
ut

l
ong-term
method, is of little use a
g
ains
t
r
p
ests. For such pests specific insecticides, which can be
stored for a
pp
lication at short notice, continue to be the most im
p
ortant tool in their control.
I
n
c
l
uded
in
t
h
e
r
-
pest group are the “classic” pests: locusts, aphids, mosquitoes, and house
fli
es (Ta
bl
e 24.3)

.
K
p
ests, on t
h
eot
h
er
h
an
d
,
h
ave
l
ower
f
ecun
di
ty an
dl
onger generat
i
on t
i
me, poor
abilit
y
to disperse, relativel
y

specialized food preferences, and are found in habitats that re-
main stable over lon
g
periods of time. Under natural conditions, insects with the features of
K
strategists seldom become pests. If, however, probably as a result of human activity, thei
r
n
i
c
h
e
i
s expan
d
e
d
(e.g., t
h
e
i
r
f
oo
d
p
l
ant
b
ecomes an

i
mportant crop), or
if
t
h
ey can occupy
ane
w
n
i
c
h
e (e.g.,
f
ee
di
ng on
d
omest
i
c catt
l
e rat
h
er t
h
an w
ild
ungu
l

ates) t
h
ey may
b
ecome
a pest. Once established, such pests are often difficult to eradicate over the short term
,
for example, throu
g
h the use of insecticides. Insecticides are frequentl
y
not feasible tools
because t
h
e
K
p
ests attack the fruit rather than the folia
g
e of crop plants, or because the cost
i
s pro
hibi
t
i
ve
i
nv
i
ew o

f
t
h
e
l
ow
d
ens
i
ty o
f
t
h
e pest popu
l
at
i
on. (In some
i
nstances,
h
owever,
wh
ere even at
l
ow popu
l
at
i
on

d
ens
i
ty a pest may cause cons
id
era
bl
e
d
amage,
f
or examp
l
e,
co
dli
n
g
mot
h
on app
l
e,
i
nsect
i
c
id
a
l

contro
l
ma
yb
e pro
fi
ta
bl
e.) Nor
i
s
bi
o
l
o
gi
ca
l
contro
l
an
a
pp
ro
p
riate method because
K
pests have few natural enemies, a feature probabl
y
related

t
o their low densit
y
under natural conditions. Fo
r
K
p
ests, the best methods of control ar
e
th
ose t
h
at
di
stur
b
t
h
e
i
r
h
a
bi
tat,
f
or examp
l
e, t
h

e
b
ree
di
ng o
f
res
i
stant stra
i
ns o
f
p
l
ant(s) o
r
an
i
ma
l
(s) attac
k
e
db
yt
h
e pests, an
d
cu
l

tura
l
pract
i
ces. Examp
l
es o
f
K
p
ests are g
i
ven
in
T
a
bl
e 24.3.
The ma
j
orit
y
of pests are classified as intermediate pests in the Conwa
y
scheme because
t
he
y
exhibit a mixture of the features o
f

r
a
n
d
K
p
ests. For some of these, with a relativel
y
h
igh reproductive potential, insecticidal control may be necessary under certain conditions
,
an
d
converse
l
y,
f
or pests approac
hi
ng t
he
K
e
n
d
o
f
t
h
e spectrum, cu

l
tura
l
contro
l
somet
i
me
s
may
b
ea
d
equate. However, t
h
e most
i
mportant
f
eature o
fi
nterme
di
ate pests
i
st
h
ere
l
at

i
ve
ly
lar
g
e number of natural enemies that the
y
have. These enemies, under normal circumstances,
are important re
g
ulators of the pest population. In addition, intermediate pests are frequentl
y
foliage- or root-damaging pests, for example, spruce budworm and some scale insects, and
,
th
ere
f
ore, t
h
e econom
i
c
i
n
j
ury t
h
res
h
o

ld i
s reasona
bl
y
hi
g
h
;t
h
at
i
s, a
f
a
i
r amount o
fd
amag
e
can
b
eto
l
erate
d
w
i
t
h
out econom

i
c
l
oss. Hence,
f
or t
h
ese pests,
bi
o
l
og
i
ca
l
contro
l
wou
ld
appear to
b
et
h
es
i
n
gl
e most appropr
i
ate met

h
o
d
o
f
contro
l
,w
hi
c
h
can
b
e supp
l
emente
d
a
s
necessar
y
with insecticidal and other methods. The latter is, in other words, an inte
g
rated
control pro
g
ram.
Wi
t
h

t
h
ese genera
l
cons
id
erat
i
ons
i
nm
i
n
d
,
i
t
i
s now appropr
i
ate to cons
id
er
i
n mor
e
d
eta
il
t

h
e met
h
o
d
sava
il
a
bl
e
f
or pest contro
l.
74
6
CHAPTER
24
4
.1. Legal Control
A
l
so
k
nown as regu
l
atory contro
l
,
l
ega

l
contro
li
s
b
ase
d
pr
i
mar
il
yont
h
eo
ld
a
d
ag
e
“
Prevent
i
on
i
s
b
etter [
i
nt
hi

s
i
nstance, c
h
eaper] t
h
an cure.” Le
g
a
l
contro
li
st
h
e enactment
o
fle
g
islation to prevent or control dama
g
eb
y
insects (Rohwer, in Pimentel, 1991, Vol. 1).
It includes, therefore, establishment of quarantine stations at ma
j
or ports of entr
y
into a
n
area. Usua

ll
yt
h
e stat
i
ons are
l
ocate
d
at
i
nternat
i
ona
lb
or
d
ers, t
h
oug
hi
n some
i
nstance
s
d
omest
i
c quarant
i

nes are necessary,
f
or examp
l
e, w
h
en certa
i
n parts o
f
a country are w
id
e
l
y
separate
df
rom t
h
e rest (Hawa
ii
an
d
cont
i
nenta
l
Un
i
te

d
States). At quarant
i
ne stat
i
ons peo-
ple and
g
oods are inspected to prevent the accidental introduction of potential insect pest
s
and plant and animal diseases. Prior to the introduction of quarantine le
g
islation in th
e
Un
i
te
d
States
i
nt
h
e ear
l
y 1900s (P
l
ant Quarant
i
ne Act o
f

1912) a num
b
er o
fi
nsect spec
i
es
h
a
db
een acc
id
enta
ll
y
i
ntro
d
uce
d
an
db
ecome esta
bli
s
h
e
d
as p
l

ant pests,
f
or examp
l
e, t
h
e
c
ottony-cus
hi
on sca
l
e
di
scusse
di
n Sect
i
on 2.3. T
h
oug
h
quarant
i
ne
h
as severe
l
yre
d

uce
d
the number of insect introductions, on avera
g
e 11 exotic species are still added annuall
y
to the insect fauna of the United States (for a total of more than 800 for the
p
eriod 1920
–
1
980). About 35% of the im
p
ortant
p
ests in the United States are introduced s
p
ecies an
d
i
nc
l
u
d
ep
i
n
kb
o
ll

worm
(
P
ectinop
h
ora
g
oss
y
pie
lla
), citrus blackfly (
Aleurocanthus wog-
(
(
l
um
i
)
, Egypt
i
an a
lf
a
lf
a weev
il (
H
y
pera

b
runneipennis),
f
ace
fl
y(Mu
s
ca autumna
l
i
s
)
, cerea
l
l
eaf beetle
(
O
ulema melano
p
u
s
), and Russian wheat aphid (
D
iura
p
his noxia
)(
Sailer, 1983
).

A
sanad
j
unct to quarantine, man
y
countries (or areas within countries) have le
g
islation tha
t
re
q
uires international or interstate shi
p
ments of animals or
p
lants, or their
p
roducts, to be
c
ert
ifi
e
d
as
di
sease- or
i
nsect-
f
ree

b
y qua
lifi
e
d
personne
l
pr
i
or to s
hi
pment.
A
l
so part o
fl
ega
l
contro
li
st
h
e sett
i
ng up o
f
surve
ill
ance systems
f

or mon
i
tor
i
ng t
he
i
nsect population in a
g
iven area so that, should an outbreak occur, it can be dealt with
before it has a chance to spread. Such surveillance is an important dut
y
of state/provincial
e
ntomolo
g
ists, in cooperation with local a
g
riculture representatives and crop and livestock
p
ro
d
ucers.
Anot
h
er aspect o
fl
ega
l
contro

l
,an
d
one t
h
at
h
as
b
ecome
i
ncreas
i
ng
l
y
i
mportant,
is
t
h
e
li
cens
i
n
g
o
fi
nsect

i
c
id
es an
d
t
h
e esta
bli
s
h
ment o
f
(1) re
g
u
l
at
i
ons re
g
ar
di
n
g
t
h
e
i
rus

e
and (2) monitorin
g
s
y
stems to assess their total impact on the environment. For example
,
i
n the United States the Environmental Protection A
g
enc
y
is responsible for assessin
g
th
e
eff
ect
i
veness o
fp
est
i
c
id
es, as we
ll
as t
h
e

i
r
p
oss
ibl
e
h
azar
d
ous e
ff
ects on
h
umans, w
ildlif
e
,
an
d
ot
h
er organ
i
sms,
i
nc
l
u
di
ng

b
ees, ot
h
er po
lli
nat
i
ng spec
i
es, an
db
ene
fi
c
i
a
l
paras
i
to
id
s. A
s
n
ote
d
ear
li
er (Sect
i

on 2.3),
i
n
di
scr
i
m
i
nate use o
fi
nsect
i
c
id
es can resu
l
t
i
n great
l
y
i
ncrease
d
rather than decreased pest dama
g
e
.
4
.2.

C
hem
i
cal
C
ontro
l
T
he use of chemicals either to kill or to re
p
el insect
p
ests is the oldest method of
pest control. Fronk (in Pfadt, 198
5
) notes that the Greeks used sulfur against pests almos
t
3
000 years ago an
d
t
h
e Romans use
d
asp
h
a
l
t
f

umes to r
id
t
h
e
i
rv
i
neyar
d
so
fi
nsect pests.
The Chinese used arsenic compounds a
g
ainst
g
arden pests before 900 A.D., thou
g
h arseni
c
was
n
ot used in the Western world until the second half of the 17th centur
y
.
Until about 1940, insecticides belon
g
ed to two ma
j

or cate
g
ories, the “inor
g
anics” an
d
t
h
e“
b
otan
i
ca
l
s.” Among t
h
e
i
norgan
i
c
i
nsect
i
c
id
es are arsen
i
can
di

ts
d
er
i
vat
i
ves (arsen
i-
c
a
l
s),
i
nc
l
u
di
ng Par
i
s green (copper acetoarsen
i
te), w
hi
c
h
was t
h
e
fi
rst

i
nsect
i
c
id
eto
be
used on a lar
g
e scale in the United States—a
g
ainst Colorado potato beetle in 186
5
. Othe
r
7
47
I
N
S
E
C
T
SA
ND
HUM
A
NS
inor
g

anics include fluoride salts (developed at about the end of the 19th centur
y
, follow
-
in
g
the realization that toxic residues were left b
y
arsenicals), sulfur, borax, phosphorus
,
mercur
y
salts, and tartar. These inor
g
anic insecticides were t
y
picall
y
spra
y
ed on the pest’
s
f
oo
dpl
ant or m
i
xe
d
w

i
t
h
su
i
ta
bl
e
b
a
i
t. In ot
h
er wor
d
s, a
ll
are “stomac
hp
o
i
sons” t
h
at re
-
qu
i
re
i
ngest

i
on an
d
a
b
sorpt
i
on to
b
ee
ff
ect
i
ve. T
h
us, t
h
ey were unsat
i
s
f
actory pest
i
c
id
es
f
or
suc
ki

n
gi
nsects
f
or w
hi
c
h
“contact po
i
sons,” a
b
sor
b
e
d
t
h
rou
gh
t
h
e
i
nte
g
ument or trac
h
ea
l

s
y
s
t
em, are necessar
y
.
The “botanicals” are or
g
anic contact poisons produced b
y
certain plants in which the
y
serve as protectants aga
i
nst
i
nsects (C
h
apter 23, Sect
i
on 3.1). Among t
h
e ear
li
est to
b
e use
d
w

ere (1) n
i
cot
i
ne a
lk
a
l
o
id
s,
d
er
i
ve
df
rom certa
i
n spec
i
es o
f
Nicotiana,
i
nc
l
u
di
n
g

N. ta
b
aca
(to
b
acco) (
f
am
il
ySo
l
anaceae); (2) roteno
id
s extracte
df
rom t
h
e roots o
fd
err
i
s(
D
erri
s
spp.) and cub´
e(
´
L
onchocar

p
us spp.); and (3) p
y
rethroids, produced b
y
plants in the
g
enu
s
P
yrethrum
(
Chrysanthemum
)(f
amily Compositae).
f
f
Because of their high mammalian toxicity, nicotine has been completely supersede
d
b
y synt
h
et
i
cs, w
hil
e rotenone use
i
snowma
i

n
l
y restr
i
cte
d
to contro
l
o
f
some suc
ki
ng pests
on crops an
d
pests o
f
pets an
dli
vestoc
k
.T
h
e pyret
h
ro
id
s, w
h
en

fi
rst ava
il
a
bl
e commer
-
ciall
y
, were an important
g
roup of insecticides for use in the home, as livestock spra
y
s,
a
nd a
g
ainst stored-product, ve
g
etable, or fruit pests, primaril
y
because of their low toxicit
y
t
o mammals. Initially, a major disadvantage of pyrethroids was their photolabile natur
e
(
i
nsta
bili

ty
i
n
li
g
h
t) an
d
t
h
e nee
d
,t
h
ere
f
ore, to reapp
l
yt
h
em
f
requent
l
yma
d
et
h
em ex-
pens

i
ve to use. T
h
us, t
h
ey were
l
arge
l
y rep
l
ace
db
yc
h
eaper, synt
h
et
i
c
i
nsect
i
c
id
es
i
nt
he
1940s, an important consequence of which was that relativel

y
few insects became resistant
t
o them. This feature, in con
j
unction with the development of several photostable s
y
n
-
t
hetic p
y
rethroids (e.
g
., c
y
permethrin, permethrin, fenvalerate, and deltamethrin), has le
d
t
o a resurgence
i
nt
h
e
i
mportance o
f
t
h
ese compoun

d
sw
hi
c
h
now account
f
or a
b
out one
thi
r
d
o
f
wor
ld i
nsect
i
c
id
e use (E
lli
ott et a
l.
,
1
978; Leahy, 198
5
; Pickett, 1988). Unfor

-
t
unate
ly
,
b
ut not surpr
i
s
i
n
gly
, para
ll
e
li
n
g
t
hi
s
i
ncrease
d
usa
g
e
h
as
b

eenama
j
or
i
ncrease
in arthropod resistance to p
y
rethroids, from fewer than 10 species in 1970 to over 80 in
2003 (Metcalf, 1989; Geor
g
hiou and La
g
unes-Te
j
eda, 1991; Resistant Arthropod Database,
2004)
.
T
h
oug
h
two synt
h
et
i
c organ
i
c
i
nsect

i
c
id
es
h
a
db
een commerc
i
a
ll
yava
il
a
bl
epr
i
or t
o
1939 (
di
n
i
trop
h
eno
l
s
i
n Germany,

fi
rst use
di
n 1892; organ
i
ct
hi
ocyanates
i
nt
h
eUn
i
te
d
States from 1932 on), it is
g
enerall
y
acknowled
g
ed that this is the
y
ear in which the s
y
nthetic
or
g
anic insecticide industr
y

took off. After several
y
ears of research for a better mothproof
-
ing compound, M¨uller, who worked for Geigy AG in Switzerland, discovered the value of
DDT as an
i
nsect
i
c
id
e. In t
h
enext
f
ew years, pro
d
uct
i
on o
f
DDT
b
egan at t
h
e company’
s
p
l
ants

i
nt
h
eUn
i
te
d
K
i
ng
d
om an
d
Un
i
te
d
States, a
l
t
h
oug
hb
ecause o
f
t
h
e Secon
d
Wor

ld
Wa
r,
knowled
g
e of DDT was kept a closel
yg
uarded secret. In earl
y
1944, DDT was firs
t
u
sed on a lar
g
e scale, in a delousin
g
pro
g
ram in Naples where t
y
phus had recentl
y
broken
out. Some 1.3 million civilians were treated with DDT, and within 3 weeks the e
p
idemic
w
a
s
controlled (Fronk, in Pfadt, 198

5
). Later that year the identity of the “miracle cure
”
wa
s
r
ev
e
a
l
e
d
,an
d
t
h
ewor
ld
soon
b
ecame conv
i
nce
d
t
h
at w
i
t
h

DDT (an
d
ot
h
er recent
ly
d
eve
l
ope
di
nsect
i
c
id
es) pest
i
nsects wou
ld b
ecome a t
hi
n
g
o
f
t
h
e past. In 1948 M¨u
ll
er was

aw
arded a Nobel Prize, thou
g
h, interestin
g
l
y
, the first example of insect resistance to DD
T
h
ad been reported 2
y
ears earlier
!
Through the 1940s and into the 1960s, much research was carried out in Western Europe
an
d
t
h
eUn
i
te
d
States
f
or ot
h
er
i
nsect

i
c
id
es as e
ff
ect
i
ve as DDT. In
i
t
i
a
ll
y, t
h
e searc
hf
ocuse
d
on ot
h
er c
hl
or
i
nate
d hyd
rocar
b
ons,

i
nc
l
u
di
n
gli
n
d
ane, c
hl
or
d
ane, a
ld
r
i
n,
di
e
ld
r
i
n, en
d
r
i
n
,
7

48
CHAPTER
24
and heptachlor, and more than 8 billion pounds were produced between 19
5
0 and 1990
(
Casida and Quistad, 1998). The use of chlorinated h
y
drocarbons in the western worl
d
wa
ss
ev
erel
y
reduced, be
g
innin
g
in the 1970s, followin
g
the development of resistance
an
d
t
h
e recogn
i
t

i
on o
f
t
h
e
h
ea
l
t
hh
azar
d
st
h
at t
h
ese
hi
g
hl
y pers
i
stent
i
nsect
i
c
id
es pose (see

b
e
l
ow). Some,
h
owever, rema
i
nt
h
ema
j
or
i
nsect
i
c
id
es
i
n some
d
eve
l
op
i
ng countr
i
es. T
h
oug

h
di
scovere
di
n 1937, or
g
anop
h
osp
h
ates suc
h
as TEPP,
di
az
i
non,
di
c
hl
orvos, parat
hi
on, an
d
m
alathion did not come to prominence as insecticides till the mid-19
6
0s. The
y
continue t

o
pla
y
a massive role, especiall
y
in a
g
ricultural pest control, with about one half of the top 2
0
s
a
l
es
li
st
b
e
i
ng organop
h
osp
h
ates (Cas
id
aan
d
Qu
i
sta
d

, 1998). Car
b
amates,
f
or examp
l
e
,
s
ev
i
n,
i
so
l
an, an
df
ura
d
an, or
i
g
i
nate
di
nt
h
e 1940s
b
ut t

h
e
i
r
i
mpact on t
h
e
i
nsect
i
c
id
e scene
w
as not seen until the late 19
6
0s. They remain important with 4 representatives in the top
2
0 insecticides sold. For details of structure, ph
y
sical properties, formulation, lethal doses
,
usa
g
e, etc., consult Fronk, in Pfadt (1985), Volume 12 of Kerkut and Gilbert (1985), Hassall
(
1990), and Szmedra, in Pimentel (1991), Vol. 1
.
Th

e searc
hf
or su
i
ta
bl
e synt
h
et
i
c
i
nsect
i
c
id
es cont
i
nues to
d
ay, t
h
oug
h
at a somew
h
at
re
d
uce

d
rate
b
ecause t
h
e pro
fi
ta
bili
ty o
f
suc
h
ventures
f
or
i
n
d
ustr
i
a
l
concerns
h
as great
l
y
diminished, for a variet
y

of interrelated reasons. The primar
y
reasons are (1) the time an
d
c
ost of discover
y
, development, and re
g
istration of an insecticide, estimated at an avera
g
e
o
f 7 years and US
$
35–45 million, with an additional US
$
55–65 million for the cost of a
production plant [by comparison, the total cost of developing a new drug is US$360 millio
n
(
Casida and Quistad, 1998)]. Only 1 in 1
5
,000–20,000 candidate chemicals ever reache
s
the marketin
g
sta
g
e; (2) the relativel

y
short “life expectanc
y
” of an insecticide because o
f
the development of resistance b
y
its tar
g
et or
g
anisms and/or its becomin
g
an environmenta
l
hazard. In contrast to the situation 20–25
y
ears a
g
o, companies now seek to maximize sales
w
ithin 3–5 years after registration; and (3) a general unwillingness of government agencie
s
to grant reg
i
strat
i
ons
f
or use o

f
new
i
nsect
i
c
id
es (an
d
,
f
or t
h
at matter, ot
h
er types o
f
c
h
em
i
ca
l
pest
i
c
id
es), as a resu
l
to

f
pressure
f
rom env
i
ronmenta
li
sts, spec
i
a
li
nterest
g
roups, an
d
t
h
e
g
eneral public. As a result, some of the lar
g
est companies in the chemical industr
y
have
e
ither considerabl
y
reduced or abandoned research into the development of new insecticide
s
(

Brown, 1977; DeBac
h
an
d
Rosen, 1991; Dent, 2000).
P
ara
ll
e
li
ng researc
hi
nto new synt
h
et
i
c
i
nsect
i
c
id
es
h
as
b
een t
h
e
di

scovery o
f
severa
l
a
ddi
t
i
ona
l
groups o
f
natura
ll
y occurr
i
ng compoun
d
sw
i
t
hi
nsect
i
c
id
a
l
act
i

v
i
ty,
f
or examp
l
e
,
the avermectins, spinos
y
ns, and azadirachtins. Avermectins, a mixture of natural products
f
rom the soil actinom
y
cete
S
treptomyces avermitilis, were discovered in the 1970s durin
g
s
creening tests for natural antihelminthic compounds (Lasota and Dybas, 1991). It was also
ob
serve
d
t
h
at t
h
ey were potent
i
nsect

i
c
id
es an
d
acar
i
c
id
es, an
d
su
b
sequent
l
y
i
vermect
i
n
an
d
a
b
amect
i
n were reg
i
stere
df

or use w
i
t
hd
omest
i
can
i
ma
l
san
d
some
h
ouse
h
o
ld
pests.
Ivermectin is also used to control onchocerciasis in West Africa and Latin America. Thou
g
h
a
v
e
rmectins are quickl
y
de
g
raded in ultraviolet li

g
ht and are stron
g
l
y
bound to soil particles,
two features that improve their safety against non-target organisms, there are situation
s
i
nw
hi
c
h
t
h
ey may pose pro
bl
ems. For examp
l
e, a
l
arge proport
i
on o
f
t
h
e avermect
i
n

s
a
d
m
i
n
i
stere
d
to
li
vestoc
k
pass unc
h
ange
d
out o
f
t
h
e
b
o
d
y
i
nt
h
e

f
eces. T
h
ese res
id
ues
rema
i
n
i
nt
h
e
d
un
g
pat
f
or severa
l
wee
k
s, to exert t
h
e
i
r tox
i
ce
ff

ects on a spectrum o
f
dun
g
-usin
g
insects, both harmful (e.
g
., various flies) and beneficial (e.
g
., dun
g
beetles)
.
The situation is particularl
y
of concern in Australia where, as noted in Section 2.5, a ran
g
e
of
exot
i
c
d
ung-
b
eet
l
e spec
i

es
h
ave
b
een
i
ntro
d
uce
d
to
d
ea
l
w
i
t
h
t
h
e mass
i
ve amounts o
f
d
ung pro
d
uce
db
y

d
omest
i
c catt
l
ean
d
s
h
eep. Avermect
i
ns
h
ave
b
een s
h
own to exert a
l
arge
n
um
b
er o
fd
etr
i
menta
l
e

ff
ects on
g
rowt
h
an
d
repro
d
uct
i
on o
f
t
h
ese
b
eet
l
es, t
h
ou
gh
t
h
ese
7
49
I
N

S
E
C
T
SA
ND
HUM
A
NS
effects can be si
g
nificantl
y
lessened b
y
careful selection of the times when livestock are
t
reated (i.e., when the dun
g
beetles are less active). However, the adoption of a sustained
-
release bolus for deliver
y
of the avermectins in livestock ma
y
haveama
j
or influence on
d
ung-

b
eet
l
e popu
l
at
i
ons (Strong, 1992; Her
d
et a
l
., 1993)
.
S
p
i
nosyns,
di
scovere
di
nt
h
e
l
ate 1980s, are pro
d
uce
db
y anot
h

er act
i
nomycete
,
S
ac-
c
h
aropo
ly
spora spinosa
.
L
ik
e avermect
i
ns, sp
i
nos
y
ns are eas
ily d
e
g
ra
d
e
dby
u
l

trav
i
o
l
et
li
g
ht and soil microor
g
anisms. The
y
have low toxicit
y
to mammals, birds, and non-tar
g
e
t
(beneficial) insects. Commercial preparations are available for control of a ran
g
e of pests
on cotton, vegeta
bl
es, tur
f
,an
d
ornamenta
l
s (Crouse an
d

Spar
k
s, 1998).
A
za
di
rac
h
t
i
n
i
st
h
ema
j
or component o
f
t
h
eo
il
extracta
bl
e
f
rom t
h
e see
d

san
dl
eaves
of the neem (margosa) tree (
Azadirachta indica
(
(
)
, an evergreen en
d
em
i
c to sout
h
ern an
d
southeastern Asia
,
but now found also in Africa
,
the United States
,
and Australia. It has
b
een shown to exert a variet
y
of potentiall
y
useful effects includin
g

inhibition of settlin
g
,
oviposition, and feeding behaviors, interference with both embryonic and postembryonic
d
eve
l
opment, re
d
uct
i
on
i
n num
b
er o
f
eggs mature
d
,an
d
morta
li
ty, an
di
t
i
se
ff
ect

i
ve on a
w
id
e range o
f
pest
i
nsects, espec
i
a
ll
yp
h
ytop
h
agous spec
i
es. Because aza
di
rac
h
t
i
n
i
spr
i-
maril
y

a feedin
g
poison for
j
uvenile ph
y
topha
g
ous insects, it shows
g
reat selectivit
y
in th
e
sense that the pests’ natural enemies (adult parasitoids and predators) are unaffected b
y
it. I
t
is also relatively non-toxic to vertebrates. Offsetting these advantages are its limited persis
-
t
ence
i
nt
h
e
fi
e
ld
,

i
ts s
l
ow-act
i
ng nature, an
d
,o
f
course, t
h
e potent
i
a
lf
or t
h
e
d
eve
l
opment o
f
res
i
stance. Nevert
h
e
l
ess,

i
t may
b
ecome a use
f
u
l
a
dj
unct to a
l
rea
d
yava
il
a
bl
e pest
i
c
id
es
in
u
nderdeveloped countries, and a few commercial preparations are available (Schmutterer
,
1990
; Isman
et al.
, 1991; Gahukar, 1995; Becka

g
e, in Rechci
g
l and Rechci
g
l, 2000)
.
Three ma
j
or problems have arisen as a result of the massive use of insecticides over
th
e past 70 years. F
i
rst, many
i
nsects an
d
m
i
tes
h
ave
d
eve
l
ope
d
res
i
stance to one or more

of the chemicals (Tables 24.4 and 24.
5
). (See Chapter 16, Section
5
.
5
for a discussion
T
A
BLE 24
.
4
.
Number of S
p
ecies of Insects an
d
M
ites in Which Resistance to
O
ne or More
Ch
em
i
ca
l
s Has Been Documente
d
a
Yea

rS
p
ecie
s
1908
1
1
9
28
5
1938
7
1948
14
1
95
42
5
1
9
57 7
6
19
6
0
137
1
963
157
1

9
6
5
185
1967
224
197
5
36
4
1
9
80 42
8
1984
447
1989
5
04
200
3
5
36
a
Data from Geor
g
hiou and Ta
y
lor (1977), Metcalf (1989)
,

Geor
g
hiou and La
g
unes-Te
j
eda (1991), and Resistant
A
rthro
p
od Database (2004)
.