Integrated Control of Apple Pests in New Zealand VII. Azinphosmethyl resistance in strains of Typhlodromus pyri from Nelson

Abstract

The mite Typhlodromus pyri Scheuten (Acari: Phytoseiidae), a predator of European red mite Panonychus ulmi (Koch), was detected in 16 of 22 surveyed apple orchards (1975) in Nelson, New Zealand. Azinphosmethyl had been used extensively on these properties for some years for codling moth and leafroller moth control, and suggestions of field tesistance to azinphosmethyl by T. pyri were confirmed in laboratory tests. Detailed toxicological examination of T. pyri from four properties established LC50 values for three strains considerably higher than previously determined values from Nelson orchards (1971). LC50 values ranged from 0.08% to 0.30% a.i. azinphosmethyl. The LC50 for the Appleby-R strain previously tested in 1971 increased from 0.07% to 0.30% from 1972 to 1976. the slopes of the dosage-mortality lines were similar for all strains. Integrated control of European red mite using T. pyri appears feasible at the detected levels of resistance. LC50 values increased curvilinearly in response to continuing exposure to azinphosmethyl, the most resistant strain having the longest history of exposure to azinphosmethyl. The implications of this relationship for integrated mite control are discussed.

Full text

This article was downloaded by: [210.55.212.231]
On: 13 November 2014, At: 20:44
Publisher: Taylor & Francis
Informa Ltd Registered in England and Wales Registered Number: 1072954 Registered office:
Mortimer House, 37-41 Mortimer Street, London W1T 3JH, UK
New Zealand Journal of Experimental
Agriculture
Publication details, including instructions for authors and subscription
information:
http://www.tandfonline.com/loi/tnzc19
VII. Azinphosmethyl resistance in strains of
Typhlodromus pyri from Nelson
D. R. Penman a , D. N Ferro a & C. H. Wearing b
a Department of Entomology , Lincoln College , Canterbury , New Zealand
b Entomology Division , DSIR , P.B., Auckland , New Zealand
Published online: 18 Jan 2012.
To cite this article: D. R. Penman , D. N Ferro & C. H. Wearing (1976) VII. Azinphosmethyl resistance in
strains of Typhlodromus pyri from Nelson, New Zealand Journal of Experimental Agriculture, 4:4, 377-380,
DOI: 10.1080/03015521.1976.10425903
To link to this article: http://dx.doi.org/10.1080/03015521.1976.10425903
PLEASE SCROLL DOWN FOR ARTICLE
Taylor & Francis makes every effort to ensure the accuracy of all the information (the “Content”)
contained in the publications on our platform. However, Taylor & Francis, our agents, and our
licensors make no representations or warranties whatsoever as to the accuracy, completeness, or
suitability for any purpose of the Content. Any opinions and views expressed in this publication
are the opinions and views of the authors, and are not the views of or endorsed by Taylor &
Francis. The accuracy of the Content should not be relied upon and should be independently
verified with primary sources of information. Taylor and Francis shall not be liable for any
losses, actions, claims, proceedings, demands, costs, expenses, damages, and other liabilities
whatsoever or howsoever caused arising directly or indirectly in connection with, in relation to or
arising out of the use of the Content.
This article may be used for research, teaching, and private study purposes. Any substantial
or systematic reproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or
distribution in any form to anyone is expressly forbidden. Terms & Conditions of access and use
can be found at http://www.tandfonline.com/page/terms-and-conditions

Integrated
control
of
apple
pests
New
Zealand
.
In
377
V
II.
Azinphosrnethyl resistance in strains of
Typhlodromus
pyri from
Nelson
By D. R.
PENMAN
AND D. N
FERRO
Department of Entomology, Lincoln College, Canterbury, New
Zealand
AND
C. H.
WEARING
Entomology Division,
DSlR,
P.B., Auckland, New
Zealand
(Received 20 July 1976)
ABSTRACT
The
mite Typhlodromus pyri Scheuten (Acari: Phytoseiidae) ,
11
predator
of
European
red mite Panonychus
ulmi
(Koch),
was
detected
in 16 of 22 surveyed
apple
orchards
(1975) in Nelson,
New
Zealand.
Azinphosrnethyl
had
been
used
extensively on these
properties
for some years
for
codling
moth
and
leafroller
moth
control, and suggestions of field
tesistance to
azinphosmethyl
by T.
pyri
were
confirmed in
laboratory
tests.
Detailed
toxicological
examination
of T. pyri from
four
properties
established LCoo values for
three
strains considerably
higher
than
previously
determined
values from Nelson
orchards
(1971).
LCoo values
ranged
from
0.08% to 0.30% a.i. azinphosmethyl.
The
LCoo
for
the Appleby-R
strain
previously tested in 1971 increased from
O.07~o
to 0.30% from 1972 to 1976.
The
slopes of the
dosage-mortality
lines
were
similar for all strains.
Integrated
control
of
European
red mite using T. pyri
appears
feasible at the
detected
levels of resistance. LCoovalues increased
curvilinearly in response to
continuing
exposure
to azinphosmethyl, the
most
resistant strain
having
the longest history of
exposure
to azinphosmethyl,
The
implications of this relation-
ship
for integrated mite
control
are discussed.
INTRODUCTION
Successful integrated control of phytophagous
mites in orchards relies mostly on predaceous
mites being resistant to commonly used orchard
spray materials. Azinphosmethyl has been used
in the Nelson region for some years in most spray
programmes to control codling moth, Laspeyresia
pomonella
(L.),
and a complex of leafroller
species. Resistance to azinphosmethyl in the
existing phytoseiid mite populations could there-
fore be expected to develop.
Resistance of predaceous phytoseiid mites to
azinphosmethyl has been reported for several
species. Typhlodromus occidentalis Nesbitt
showed azinphosmethyl resistance in the western
U.S. (Croft &Jeppson 1970)
and
resistance of
Amblyseius
fallacis (Garman) has been reported
by several workers (Motoyama et al. 1970; Rock
&Yeargan 1971; Ahlstrom &Rock 1973; Croft
&Meyer 1973; Croft et al.
1976).
Hoyt (1972)
recorded comparatively low levels of resistance
in
Typhlodromus
pyri Scheuten to azinphos-
methyl in Nelson, New
Zealand
and Watve &
Lienk (1975, 1976) have recently found higher
levels of resistance to azinphosmethyl to occur in
the latter species in New York.
Hoyt
(1972) considered resistance levels in
T. pyri in New Zealand too low to enable the
predators to survive repeated applications of
azinphosmethyl. After the suggestion of Hoyt
(1973)
that
monitoring of T. pyri populations
may indicate major changes in susceptibility of
that
species to chemicals, asurvey was conducted
in the Nelson district during January 1975. Six-
teen of 22 orchards contained T. pyri (Wearing &
Penman
1975).
This
paper
reports on the pre-
liminary assessment in January 1975 of resistance
in field-collected T. pyri,
and
amore detailed
toxicological investigation in December 1975 and
January 1976 of T. pyri
from
selected properties.
METHODS
Preliminary
assessment
of
resistance
1'. pyri was field-collected in Nelson and whole
N.Z. Journal of Experimental Agriculture 4: 377-80
Downloaded by [210.55.212.231] at 20:44 13 November 2014

378
N.Z.
JOURNAL
OF
EXPERIMENTAL
AGRICULTURE,
VOL.
4, 1976
leaves containing
both
predators and prey were
air-freighted in plastic bags to Lincoln College
for testing.
Number
of live
predators
recovered
varied considerably depending on time in transit
and
the necessity for storage of some samples
before testing. Samples were collected before
spray applications so residues
would
be expected
to be minimal. Only vigorous active female
T.
pyri
were
selected for testing. However, many
T. pyri
often
died while in transit.
Resistance was assessed using the slide-dip
technique similar to
that
described for Tetrany-
chus urticae (Anon. 1968). Resistance was pre-
liminarily assessed at one concentration of azin-
phosmethyl, viz.,
0.07%
a.i.,
which
was
the
LC50
value
obtained
by Hoyt (1972) for the resistant
strain of T. pvri. Percent mortality at
that
con-
centration indicated
which
populations
were
worthy of
further
detailed study.
Twenty
to 30
adult
female T. pyri were
placed
on their backs
on double-sided sticky tape
attached
to a micro-
scope slide. All toxicant solutions
were
prepared
from a
50%
wettable
powder
formulation of
azinphosmethyl in distilled
water.
Slides were
dipped for 5sec
and
excess
liquid
was
removed
from
the
slides
with
blotting
paper.
Control
slides
were
dipped
for 5sec in distilled water.
Treated slides were held in an
incubator
at
27°e
and
80 ±
10%
RH for 24 h. Mortality was
determined by the failure of the mites to move
their appendages
when
touched by a fine brush.
Deterrnination
of
resistance
levels
Whole-leaf samples containing T.
pyri
and
prey
species
were
recevied at intervals from selected
properties in Nelson. Problems
with
transport
occurred, similar to those experienced
with
the
earlier survey samples. Insufficient live predators
were available for adequate
numbers
to be tested
from some properties.
Dosage-mortality
data
were
obtained
by the
slide-dip technique. Up to six concentrations of
the
50%
wettable
powder
formulation
of azin-
phosmethyl were used plus a distilled
water
control.
Twenty
adult female T. pyri were placed
on
each
microscope slide
and,
where
possible,
80 T. pyri were treated at each dosage level.
Treated
slides were held at
nOe
and
80 ±10%
RH for 24 hbefore determination of mortality.
LC;;o
values were obtained by plotting
dosage-
mortality
data
on log-probit
paper
and
fitting the
lines from
probit
analysis.
RESULTS
Preliminary
assessment
of
resistance
Of the 16 orchards
where
T. pyri was found
in
the
survey, 12
had
sufficient
predators
for a
preliminary assessment of resistance to azinphos-
methyl. Eleven samples
had
been
exposed to
regular azinphosmethyl applications,
and
one
sample was from the
DSIR
Appleby Research
Orchard,
which
had
never
been
sprayed
with
azinphosmethyl. At an azinphosmethyl con-
centration of
0.07%
a.i., corrected mortalities in
the survey orchards ranged from
9.0%
to
45.0%
(mean 22.3
%)
.
The
corrected mortality for
the susceptible predators (Appleby Research
Orchard)
was
64.6%.
.
The
comparatively low mortality
(22.3%)
of
T. pyri to azinphosmethyl at the
LC50
value
determined by Hoyt (1972) suggested
that
populations of T.
pvri
existed
with
asubstantially
greater level of resistance
than
previously deter-
mined. Determination of LC50 values was con-
fined to four properties
where
T. pyri occurred
in large numbers and was giving some measure
of mite control in spite of
continued
application
of azinphosmethyl.
Determination
of
resistance
levels
The
dosage-mortality lines for the four tested
strains are
shown
in Fig. 1. Unfortunately, high
transit mortalities in a strain having no history
of azinphosrnthyl applications
prevented
strains
being
compared
with
asusceptible strain.
Table
1presents details of the toxicological
responses of each strain. Testing the strains at
TABLE 1- Toxicity of azinphosmethyl to field-collected strains of
Typhlodromus
pyri
Strain Date tested LC50t
95%
conf.
LCD(it
Slope
limits for
LC50
Kilmartin
(13):1:
17 Dec 1975 0.16 0.12-0.22 1.63 1.63
Wells (9) 20 Tan 1976 0.08 0.06-0.10 0.93 1.52
Stucke (15) 27
Tan
1976 0.25 0.21-0.30 1.54 2.09
Appleby-R (16) 23 Feb 1976 0.30 0.19-0.46 5.87 1.25
Appleby-R (9) 1971 0,07
tExpressed as %active ingredient
tNumber of seasons usage of
azinphosmethyl
including the current season, 1975-76
Downloaded by [210.55.212.231] at 20:44 13 November 2014

PENMAN
ct al.:
INTEGRATED
CONTROL
OF
ApPLE
PESTS.
Vl I 379
NUM~ER
YEAgS
EXPOSUR,::
-:0
:\ZINPHOSMETI-l:,'L
Fig. 2- Relationship betwen
LC"o
values for field
collected strains of T. pyri and the number of year:
of exposure to
azinphosmethyl
The year tested i
given in parenthesis.
15
L
AP P,e b YF
rl97S-Gl
Stucke
(1975-6)
/
10
A~.------
~O
-lli!!.:1L-
__
5O----
Wells
(1975-6
"Appleby
R
(19";O-1)
LC 50 I
L
..
o
..-
_ .
0"-----
0·8"
-
'--'3'0-
50
PERCENT
al-AZINPHOSMETHYL
Fig. 1- Dosage-mortality lines for the four strains
of
Tvphlodromus
pyri treated with azinphosmethyl.
'l
_Kilmartin; A _ Wells; II _ Stucke; 0 - Appleby-
R.
different dates may
have
affected
the
toxicological
responses, depending on
the
selection pressure
from azinphosmethyl applied at
that
point in the
season. However, only the Wells strain
with
a
LC31l
value
of
0.08%
approximated
the toxico-
logical responses
shown
by
Hoyt
(1972) for
T. pyri (R. strain
LCilO
=
0.07%;
Slope =
2).
The
other
three strains all
had
LCilO
values
greater
than
that
for the Wells strain.
The
slope
values
were
similar to values
obtained
by
Hoyt
(1972)
and
the slopes of
the
dosage-mortality
lines
were
similar for all strains tested.
The
LC95
values suggest
that
high concentrations
would
be
necessary for complete
mortality
of T. pyri. Con-
versely, there could still be relatively high
mortalities at comparatively
low
concentrations.
The
LC~o
for the tested strains was highest in
the strains with the longest history of exposure to
azinphosmethyl
(Table
1).
By
incorporating
the
LC:;o
values
obtained
by
Hoyt
(1972) for the
Appleby-S
strain
(no azinphosmethyl exposure)
and
the Appleby-R
strain
(9 years' azinphos-
methyl
exposure),
and
plotting
the
LC:;o
values
against the
number
of years
exposure
to azinphos-
methyl (Fig.
2),
LC:;o
values increased in
response to continuing
exposure
to azinphos-
methyl. All strains have
been
exposed to full
commercial
rates of azinphosmethyl except for
the Appleby-R
strain
which
was treated at the
rate of
0.025%
a.i. in the
1974-75
season.
DISCUSSION
Resistance to azinphosmethyl in T. pyri ir
Nelson
has
apparently
become
much
more wide
widespread
since the initial survey by Hoy
(1972) .Hoyt failed to find resistant strains
01
T. pyri in any orchards
other
than
the Appleby
Research
Orchard
where
a
strain
was found in
1967-68
(Collyer
1976).
Azinphosmethyl has
remained
the
dominant
chemical in spray pro-
grammes for control of leafroller species
and
codling
moth,
and
the
continued
pressure
had
led to the selection of resistant strains of T. pyri.
Asignificant
proportion
of Nelson
orchards
now
appears
to have T. pyri
populations
resistant to
azinphosmethyl.
Detailed
toxicological
examination
shows the
selection for resistance in T. pyri was
not
com-
plete at the time of testing by Hoyt (1972).
T. pyri has increased its resistance;
where
the
LC"o of the Appleby-R
strain
in 1971 was
0.07%
it is
now
0.3%.
The
LC"f)
values for the most resistant strains
closely
approximate
those detected for othei
species of
predatory
mites in response te
azinphosmethyl.
A.
fallacis
had
an LC"o value
of 0.43 %in tests
conducted
by Motoyama et al
(1970)
and
T. occidentalis
had
an 0.203 %
LC;;l
value (Croft &reppson
1970).
Watve
&Lienk
(1976)
found
LC"f)
values of resistant strains oi
T. pyri in
New
York
to range from
0.140%
te
0.234%.
Successful integrated mite control pro
grammes have been
based
on the former twc
phytoseiid mites.
Thus
we
can
assume
that
pro-
vided
other
harmful
pesticides are not used, the
level of resistance found in T. pyri is sufficient tr
provide
a basis for integrated
control
of Europeai i
red mite. Recent results
with
Appleby-R strai: i
confirm this view (E. Collyer pel's.
comm.).
Downloaded by [210.55.212.231] at 20:44 13 November 2014

31'0 N.Z.
JOURNAL
OF
EXPERIMENTAL
AGRICULTURE,
VOL.
4, 1976
The reJationship between the
LCiJa
values and
the
number
of years of exposure to azinphos-
methyl has implications for integrated mite
control.
Hoyt
(1973)
suggested
that
the resistance
level to azinphosmethyl in T. pyri in Nelson was
too low (Appleby-R
LCiJa
=
0.07%)
to permit
sufficient
predator
survival to control mite
populations
when
they have been treated
with
full
commercial rates of azinphosmethyl. Resistance
levels have increased after continued exposure to
azinphosmethyl and T. pyri is surviving cornmer-
cial rates of azinphosmethyl. Probably orchards
will require at least 10 years of azinphosmethyl
usage before resistance levels in T. pyri are sufh-
cient to permit adequate
predator
survival.
Orchardists moving to integrated mite control
should select blocks
with
an extensive history or
azinphosmethyl usage before relying on T. pyrt
to provide an effective adjunct to mite control by
chemicals.
Acknowledgmenls
Miss J.
Dunbar,
Mrs T. Cowie, Miss A. Greene,
and Mr R. B.
Chapman
for technical assistance in
conducting the tests. Mr J. Walker,
and
other
staff
of DSIR, Ministry of Agriculture
and
Fisheries, and
the N.Z. Fruitgrowers' Federation for field collections.
REFERENCES
Ahlstrom, K. R.; Rock, G. C. 1973 Comparative
studies on Neoseiulus fallacis
and
Metaseiulus
occideniaiis for azinphosmethvl toxicity and
effects of prey and pollen on growth.
Annals
of
the
Entomological
Society
of
America
66:
1109-13.
Anon. 1968: First conference on test methods for
resistance in insects of agricultural importance.
Bulletin
of
the
Entomological
Society
of
America
14:
31-7.
Collyer, E. 1976: Integrated control of apple pests in
New
Zealand
6. Incidence of
European
red mite,
Panonychus
ulmi
(Koch) and its predators.
N.Z.
journal
of Zoology 3: 39-50.
Croft, B. A.; Jeppson, L. R. 1970: Comparative
studies on four strains of Typhlodromus occi-
dentalis.
II.
Laboratory toxicity of ten com-
nounds
common to apple pest control. journal
of
Economic
Entomology
63: 1528-31.
Croft, B. A.; Meyer, R. H. 1973: Carbamate and
organophosphorus resistance patterns in popula-
tions of Amblvseius [allacis.
Environmental
Entomology
2: 691-5.
Croft, B. A.; Brown, A. W. A.; Hoying, S. A. 1976:
Organophosphorus-resistance and its inheritance
in the predaceous mite
Amblyseius
fallacis.
[ournal
of
Economic
Entomology
69: 64-8.
Hoyt, S. C. 1972: Resistance to azinphosmethyl of
Typhlodrornus
pyri (Acarina: Phvtoseiidae) from
New
Zealand. N.Z.
journal
of Science 15:
16-21.
Hoyt, S. C. 1973: Studies on integrated control of
Panonychus ulmi in New
Zealand
apple orchards.
N.Z.
journal
of
Experimental
Agriculture
1:
77-80.
Motoyama, N.; Rock, G. C.;
Dauterman,
W. C. 1970:
Organophosphorus
resistance in an apple
orchard
population of Typhlodromus
(Ambly-
seius) [allacis.
journal
of
Economic
Entomology
63: 1439-42.
Rock, G. C.; Yeargan, D. R. 1971: Relative toxicity
of pesticides to organophosphorus-resistant
orchard
populations of Neoseiulus fallacis and its
prey.
journal
of
Economic
Entomology
64:
350-52.
Watve, C.
1'11.;
Lienk, S. E. 1975: Responses of two
phytoseiid mites to pesticides used in New
York
apple orchards.
Environmental
Entomology
4:
797-800.
1976: Toxicity of Carbaryl and siz
organophosphorus insecticides to Amblyseius
[allacis
and
Typhlodromus
pyri
from New York
apple orchards. Ibid. 5: 368-70.
Wearing, C. H.; Penman, D. R. 1975: Survey for
insecticide-resistant predatory mites in Nelson,
1974-75. Orchardist of
NiZ,
48: 122.
Downloaded by [210.55.212.231] at 20:44 13 November 2014