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 Abstract
 Materials and methods
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Group Title: Journal of Economic Entomology, 94 (4). pp. 905-910.
Title: Evaluation of Various Deployment Strategies of Imidacloprid-Treated Spheres in Highbush Blueberries for Control of Rhagoletis mendax (Diptera: Tephritidae).
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Title: Evaluation of Various Deployment Strategies of Imidacloprid-Treated Spheres in Highbush Blueberries for Control of Rhagoletis mendax (Diptera: Tephritidae).
Series Title: Journal of Economic Entomology, 94 (4). pp. 905-910.
Physical Description: Book
Creator: Stelinski, Lukasz L.
Liburd, Oscar E.
Publisher: Entomological Society of America
Publication Date: 2001
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Subject: University of Florida.   ( lcsh )
Spatial Coverage: North America -- United States of America -- Florida
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Volume ID: VID00001
Source Institution: University of Florida
Holding Location: University of Florida
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Table of Contents
    Abstract
        Page 905
    Materials and methods
        Page 906
    Results
        Page 907
    Discussion
        Page 908
    Acknowledgments and references
        Page 909
        Page 910
Full Text





HORTICULTURAL ENTOMOLOGY


Evaluation of Various Deployment Strategies of Imidacloprid-Treated
Spheres in Highbush Blueberries for Control of J.ThigJle ;.; mendax
(Diptera: Tephritidae)


I,UKASZ L. STEIANSKI AND OSCAR E. I BUIRD

Department i i ....... Center for Integrated Plant Systems, Michigan State University, East Lansing, MI 48824



J. Econ. Entomol. 94(4): 905 910 (2001)
ABSTRACT Biodegradable, ammonium-baited spheres treated with the neonicotinoid insecticide
Provado (imidacloprid) at 2% (AI) were evaluated for controlling blueberry i ... .- ., ,
mendax Curran. Three strategies for sphere deployment in highbush blueberries, Vaccinium corym-
bosum I., were compared with untreated control plots in 1999 and once again compared against
control plots and organophosphate insecticide sprays in 2000. The patterns of sphere deployment
were as follows: (1) perimeter deployment in which spheres were hung individually and spaced
equally around the perimeter of experimental plots; (2) cluster deployment in which four groups
of three spheres were hung in i ii. spaced perimeter locations of experimental plots; and (3)
uniform deployment in which spheres were placed 10 m apart (in a .. i i.i pattern) within
experimental plots. In 1999. there were no ... -.' differences in fruit injury levels based on
observed R. miendax oviposition scars and reared larvae among plots containing imidacloprid-treated
spheres in perimeter, cluster, and internal-grid patterns. However, all plots containing spheres had
S, .. i lower fruit infestation levels (<2%), compared with unsprayed control plots with no
spheresdeployed,whichhad infestation levels (>20%).In2000, there were no .....: .... .
in fruit injury based on observed R. mendax oviposition scars between plots containing imidacloprid-
treated spheres in the three deployment strategies tested and plots that received Guthion (Azinphos-
methyl) spray applications. lowevi _, I i fewer R. mendax larvae were reared from berries
collected from plots that received two applications of Guthion compared with plots in which
imidacloprid-treated spheres were deployed. Irrespective of sphere deployment strategies, all
sphere-treated and sprayed plots had significantly lower injury levels (<1.5%), based on numbers
of reared larvae compared with berries collected from the control plots (>4.0%). Based on captures
of flies on unbaited Pherocon AM boards placed in the center of treatment plots, we observed a
suppression of R. mendax in plots containing imidacloprid-treated spheres compared with control
plots. The potential of using imidacloprid-treated spheres as a behavioral control integrated pest
management tactic for blueberry maggot flies is discussed.


....... i. i. 1-treated spheres, deployment strategies, behavioral


KEY WORDS .
control


GIVEN THEIR STATUS as insect pests of economic signif-
icance, species within the genus Rhagoletis have been
the subject of a vast number of studies focusing on the
development of integrated management strategies
(Boller and Prokopy 1976, AliNiazee 1978, Prokopy et
al. 1990, Liburd et al. 1999). Many of these studies have
concentrated on the development and optimization of
monitoring techniques (Kring 1970, Prokopy and
Hauschild 1979, Drummond et al. 1984, Liburd et al.
2000) for early-season detection of adult flies. I I -
tive monitoring techniques for fruit :... .- .- '. ;.1,..:
ids are of great importance given the strict tolerance
levels imposed on maggot infested fruit (Liburd et al.
2000). Additionally, sensitive monitoring of adult flies
in commercial settings can potentially reduce unnec-
essary, prophylactic pesticide applications.

1 Department of Entomology and Nematology, University of Flor-
ida, Gainesville, FL 32611.


In addition to the optimization of monitoring tech-
niques for key Rhagoletis species, a considerable
amount of research has dealt with the development of
behavioral control methods designed to complement
existing management techniques, such as pesticide
spray applications (Prokopy and Mason 1996). Many
of the behavioral control tactics involve the exploita-
tion ,iii .. to visual and .h stimuli using
fruit- or foliage-mimicking sticky traps baited with
food- or host-fruit-mimnicking synthetic attractants
(Russet al. 1973, Neilson et al. 1981, Stanley et al. 1987,
Duan and Prokopy 1992). In addition to their effec-
tiveness as monitoring devices. Prokopy et al. (1990)
showed that appropriately baited and .., .ii attrac-
tive traps had the potential of reducing fruit injury
when deployed within orchards to intercept immi-
grating adult apple maggot flies, ..r... .........
(Walsh). Furthermore, Reynolds et al. (1998) found
that both perimeter and within-orchard deployment


0022-0493/01/0905-0910$02.00/0 ( 2001 Entomological Society of America






JOURNAL OF ECONOMIC ENTOMOLOGY


patterns of odor-baited red sticky spheres reduced
oviposition by apple maggot flies compared with con-
trol blocks without such traps.
The use of odor-baited sticky traps (Neilson et al.
1981, Liburd et al. 1998b) and biodegradable attract-
and-kill devices (Liburd et al. 1999, Ayyappath et al.
2000) have been evaluated against Rhagoletis mendax
Curran and have potential for implementation as be-
havioral control tactics. Liburd et al. (1999) reported
that biodegradable, fruit-mimicking spheres treated
with imidacloprid (Bayer, Kansas City, MO) effec-
tively killed both blueberry maggot and apple mag-
got flies in field studies. In a later study, Ayyappath
et al. (2000) demonstrated that biodegradable spheres
treated with the neonicotinoid insecticide Actara
(thiomethoxam) (Novartis, Greensboro, NC) were
also effective in killing blueberry maggot flies in blue-
berry plantings. The results of this same study revealed
that increasing the dosage of thiomethoxam used with
biodegradable spheres prolonged their effectiveness
when deployed in the field. Most recently, Prokopy et
al. (2001) showed that both wooden and biodegrad-
able insecticide-treated spheres were only slightly less
effective than the use of organophosphate sprays or
sticky red spheres in preventing fruit injury by R.
pomonella.
The potential benefits of using insecticide-treated
spheres instead of organophosphate applications or
odor-baited sticky traps for control of R. mendax has
been cited in recent studies (Liburd et al.1999, Ayy-
appath at al. 2000). However, there are no detailed
studies demonstrating how insecticide-treated sphere
deployment tactics within highbush blueberries, Vac-
cinium corymbosum L., affect the status of resident or
immigrant populations of blueberry maggot flies. Also,
no direct comparisons of conventional organophos-
phate sprays versus deployment of insecticide-treated
spheres have been made with respect to controlling R.
mendax. Consequently, there has been no documen-
tation of preventing fruit injury caused by blueberry
maggot fly oviposition with the use of insecticide-
treated spheres.
The objective of this study was to evaluate three
potential insecticide-treated sphere deployment pat-
terns in highbush blueberry plantings to determine
how they may impact fruit injury and infestation levels
of R. mendax. Furthermore, the study aimed to com-
pare insecticide-treated spheres, as a behavioral con-
trol tactic for blueberry maggot flies, with conven-
tional spray applications of an organophosphate.

Materials and Methods
Field experiments to determine the effectiveness of
biodegradable spheres treated with the neonicotinoid
insecticide Provado (Imidacloprid) (Bayer, Kansas
City, MO), for the control of blueberry maggot flies
were conducted at an experimental blueberry farm in
Douglas, MI, in 1999 and 2000. Biodegradable spheres
(9 cm diameter), made with the specifications out-
lined in Liburd et al. (1999), were obtained from the
United States Department of Agriculture (USDA) lab-


SPerimeter ) Cluster

(0 0 __ (C] (C)-M


Internal-grid Untreated
0 0 0 0


Fig. 1. Imidacloprid-treated sphere deployment strate-
gies in highbush blueberry plots (10 by 40 m). 9-cm-
diameter, green imidacloprid-treated sphere.

oratory in Peoria, IL. Spheres were brush-painted with
two coats of a mixture containing DevFlex latex green
paint (ICI Paints, Cleveland, OH) (70%), sucrose
feeding stimulant (20%), water (8%), and imidaclo-
prid at 2% (AI) (Liburd et al. 1999). Spheres were
allowed to dry for 72 h before field deployment. Bio-
degradable spheres were hung within the canopy of
blueberry bushes within the cultivar Jersey at a height
-15 cm below the tops of the uppermost bush ac-
cording to the recommendations of Liburd et al.
(2000). Biodegradable spheres used in blueberry mag-
got experiments were baited with polycon dispensers
(Great Lakes IPM, Vestaburg, MI). The dispensers
were attached to the strings used for hanging spheres
and contained 5 g of ammonium acetate (Liburd et al.
1998b). The experimental designs were completely
randomized blocks with four replications.
1999. The experiment was designed to determine
the most effective strategy for deploying (arrange-
ment and interval distance) imidacloprid-treated
spheres to control R. mendax and consequently pre-
vent maggot injury and infestation. The experimental
plots were 10 by 40-m rectangles, containing three
rows of 12 highbush blueberries. Treatments were
randomly assigned to the experimental plots con-
tained within larger blueberry plantings. All treat-
ment/replicate plots were spaced at least 20 m apart
and treatments were assigned randomly with respect
to field borders. During both years of the experiment,
no insecticides were used in areas where imidaclo-
prid-treated spheres were deployed. Twelve biode-
gradable, imidacloprid-treated spheres were used in
each treatment/replicate (Fig. 1). The four treat-
ments evaluated were as follows: (1) perimeter de-
ployment in which spheres were hung individually
and spaced equally around the perimeter of experi-
mental plots (Fig. 1); (2) cluster deployment in which
four groups of three spheres were hung in equally
spaced perimeter locations of experimental plots (Fig.
1); (3) uniform deployment in which spheres were
placed 10 m apart (in a grid-like pattern) within ex-
perimental plots (Fig. 1); and (4) untreated experi-
mental plots containing no spheres (Fig. 1). All
spheres were deployed on 30 June after the detection
of the first adult blueberry maggot on Pherocon AM
yellow sticky boards (Great Lakes IPM).


Vol. 94, no. 4






STELINSKI AND LIBURD: STRATEGIES OF IMIDACLOPRID-TREATED SPHERES


Fruit Evaluation. At the end of the growing season
(5 August), 300 ripe blueberries (majority of berries
turned blue aro und stem) were picked at random from
each experimental plot and kept separate according to
treatment. From each batch of 300 berries, 50 were
randomly selected and examined under a magnifying
lens for blueberry maggot fly oviposition scars. The
numbers ofberries with oviposition scars were used to
calculate percentage of fruit injury. All 300 berries
from each replicate were then placed over 0.5 cm
mesh hardware cloth to allow larvae to exit the fruit
and drop into containers filled with vermiculite
(Liburd et al. 1998b). The vermiculite was sifted and
blueberry maggot fly puparia were ii i and
counted to quantify fruit infestation.
2000. During our second field season, we evaluated
the same three imidacloprid-treated sphere deploy-
ment strategies as described for 1999 and compared
deployment tactics with standard treatment of Gu-
thion 50 W (Azinphos-methyl) (Bayer) sprays. Azin-
phos-methyl sprays were made on 15 June, and 6 and
25 July with a tractor air-blast sprayer (Air-O-Fan,
Reedley, CA). Plot sizes and experimental designs in
2000 were identical to those described for 1999; plots
receiving Azinphos-methyl sprays were spaced 50 m
or further away from sphere-treated plots. The five
treatments evaluated were as follows: (1) perimeter
sphere deployment; (2) cluster sphere deployment;
(3) uniform sphere deployment; (4) two applications
of Guthion 50 W at a rate of 1.7 kg/ha; and (5) un-
treated experimental plots containing no spheres or
Azinphos-methyl sprays. All spheres were deployed
on 20 June.
Fruit Evaluation. At the end of the growing season
(8 August), 1,200 ripe blueberries were picked at ran-
dom from each experimental block and fruit was kept
separate according to treatment. Similar to our pro-
cedure in 1999, we randomly selected 50 from each
batch of 1,200 and examined them under .. ..1 n*i .
lens for R. mendax oviposition scars. The numbers of
berries with oviposition scars were again used to cal-
culate percentage of fruit injury. All 1,200 berries from
each replicate were then placed over 0.5-cm mesh
hardware cloth as described for 1999 and blueberry
maggot fly puparia were later collected and counted
to : .'.... d fruit infestation.
Monitoring. During the second year of our study
(2000), two unbaited Pherocon AM yellow sticky
boards (Great Lakes IPM) were hung 20 m apart in the
center of each treatment plot to monitor R. mendax
activity within treatments. Traps were positioned in
the V-shaped orientation (folded into a 450 angle with
apex downward and sticky surface outwards)
(Prokopy and Coli 1978). Flies were counted and
removed from traps two times per week and traps
were replaced in the field every 2 wk.
Statistical Analysis. Percentage data from fruit in-
jury analysis were acrsine transformed and fly moni-
toring data were square-root transformed (x + 0.5) to
stabilize variances and then subjected to an analysis
of variance (ANOVA). Least significant itn. .- -
(LSD) tests were used to show treatment mean dif-


Table 1. Percentage of fruit injury due to R. men dax ovipo-
sition (Michigan, 1999)

Control strategy % of fruit injury


Perimeter deployment of spheres
Internal deployment of spheres
Cluster deployment of spheres
Untreated plots (control)


Perimeter deployment of spheres
Internal deployment of spheres
Cluster deployment of spheres
Untreated plots (control)


oviposition scars from
50 blueberries
0.3 0.3b
0.3 0.3b
00 O.Ob
3.7 0.2a
% puparia from
300 blueberries
1.3- 0.6b
1.0 1.Ob
1.8 + 0.3b
21.0 2.4a


Mean I SE within each experiment followed by the same letter are
not significantly different, (P = 0.05 LSD test).


ferences (P = 0.05) (SAS Institute 1989). The un-
transformed means and standard errors are presented
in tables.

Results
1999. Significantly more oviposition scars (F = 29.1;
df = 3, 9; P < 0.01) and puparia (F = 71.1; df = 3, 9;
P < 0.01) were recorded from blueberries that were
collected from the untreated plots (not containing
spheres) compared with berries from plots that con-
tained imidacloprid-treated spheres, regardless of
their deployment pattern (Table 1). The numbers of
oviposition scars in untreated blocks were three times
higher than sphere-treated blocks. Likewise, the num-
bers of puparia in untreated blocks were 11.6 times
higher than in sphere-treated blocks. We recorded no
significant in. .- in the numbers of R. mendax
oviposition scars and puparia from blueberries col-
lected from plots containing imidacloprid-treated
spheres in the three deployment strategies tested (Ta-
ble 1). Finally, the percentages of fruit injury based on
oviposition scars and puparia recorded were < 1 and
2%, respectively, in all plots containing imidacloprid-
treated spheres (Table 1).
2000. The results of our second year's study were
similar to those observed in 1999. ...... (F =
21.3; df = 4, 12; P < 0.01) more oviposition scars and
puparia (F = 10.1; df = 4, 12; P < 0.01) were found on
berries picked from untreated control plots compared
with plots containing imidacloprid-treated spheres or
plots sprayed with Guthion (Table 2). Untreated
(control) plots had >2.5 times as many oviposition
scars or puparia compared with any of our plots
treated with imidacloprid-treated spheres or Guthion
sprays. We did not record any significant I.. ....
in the numbers of R. mendax oviposition scars or pu-
paria from berries collected from plots containing imi-
dacloprid-treated spheres in the three deployment
strategies tested (Table 2). An important finding was
that there were no significant differences in fruit in-
jury, based on oviposition scar data, between plots
containing imidacloprid-treated spheres and those


August 2001






JOURNAL OF ECONOMIC ENTOMOLOGY


Table 2. Percentage of fruit injury due to R. menadax ovipo-
sition (Michigan, 2000)

Control strategy % of fruit injury
% oviposition scars from
50 blueberries
Perimeter deployment of spheres 4.0 1.81
Internal deployment of spheres 4.0 0.8b
Cluster deployment of spheres 46 1.0b
Cuthion spray (organophosphate) 20 0.8b
Untreated plots (control) 11.6 1.0a
% puparia from
1200 blueberries
Perimeter deployment of spheres 1 3 0-3b
Internal deployment of spheres 0.8 0.lb
Cluster deployment of spheres 1.0 0.2b
Cuthion spray (organophosphate) 0.1 0.1e
Untreated plots (control) 3.9 0.7a

Means SE within each experiment followed by the same letter are
not significantly different, (P = 0.05, LSD test).

sprayed with Guthion (Table 2). However, plots
treated with Guthion had ,-,,i,. .... (F = 10.1; df=
4, 12; P < 0.01) fewer puparia compared with plots
containing imidacloprid-treated spheres (Table 2).
In our monitoring program, significantly (F = 9.3;
df = 4, 12; P < 0.01) more R. inendax flies were
captured on Pherocon AM boards placed within con-
trol plots compared with fly captures in plots contain-
ing imidacloprid-treated spheres in perimeter, uni-
form, and cluster orientations and plots sprayed with
Guthion (Table 3). There were no significant differ-
ences in the numbers of blueberry maggot flies cap-
tured on unbaited Pherocon AM boards within plots
containing imidacloprid-treated spheres, ,. _.. II of
deployment pattern, ard plots sprayed with Guthion
(Table 3).

Discussion
Our results showed that deployment of irnidaclo-
prid-treated, biodegradable spheres decreased blue-
berry infestation levels to 1% in 1999 and 0.8% in 2000
(with internal-grid deployment patterns), whereas
untreated (control) plots had maggot infestation lev-
els >20% and >3.2% in 1999 and 2000, respectively. In
both years, there were no differences in fruit injury
levels obtained using the three different strategies for
sphere deployment. Several factors may have contrib-
uted to the observed. ,... ..: ... !:: 1. . in-
cluding that the blueberry planting used in our ex-

Table 3. Mean number of R. mendax captured on unbaited
Pherocon AM boards within treatment plots (Michigan, 2000)

Control strategy No. of R. mendax


Perimeter deployment of spheres
Internal deployment of spheres
Cluster deployment of spheres
Guthion spray (organophosphate)
Untreated plots (control)


20.0 4.4b
19.3 1 2.8b
16.5 2.1b
14.5 2.8b
47.0 5.3a


Mean SE (25 June 8 Aug.) within each experiment followed by
the same letter are not significantly different, (P = 0.05, LSD test).


periments had a residential population of R. mendax
flies (emerging from within the planting), as well as
immigrating populations invading from the surround-
ing areas and natural bogs. Perimeter trapping tactics
could be effective in intercepting immigrants
(Prokopy et al. 1990) into the planting, but the degree
of fruit protection from fly oviposition is dependent on
trap spacing, the pressure of immigrating flies, and
field status with respect to the presence or absence of
residential blueberry maggot fly populations. By con-
trast, the internal-grid pattern of sphere deployment
may hold more potential in suppressing adult blue-
berry maggot :,. and preventing fruit infestation in
plantings harboring re i .i ..* i1 1 populations. Again,
the effectiveness of the internal-grid pattern is depen-
dent on the degree of sphere spacing and fly popula-
tion densities within the planting. Also, factors such as
fruit load, degree of fruit maturity. and the physiolog-
ical status of R. mendax (Liburd and Stelinski 1999)
may -.il. 1. the effectiveness of the internal-grid
deployment pattern. Overall, our experiments have
implied that specific sphere placement patterns (pe-
rimeter versus internal-grid) may be less important in
blueberry plantings that are exposed to both residen-
tial and immigrating R. mendax populations.
The observed nonsignificant differences among the
deployment strategies tested also may have been due
to equal levels of visual and olfactory stimuli provided
by the odor-baited, fruit-mimricking spheres in each
treatment plot. Given the strong attraction of R.
mendax to 9-cm-diameter green spheres baited with
ammonium acetate (Liburd et al. 1998a, 2000), it is
possible that flies foraging within each of our plots had
approximately equal ... 1 .1 .. of encountering the
bait-odor or visual stimulus provided by the irnidaclo-
prid-treated spheres, irrespective of sphere deploy-
ment patterns. Therefore, the nonsignificant differ-
ences among deployment strategies may have been
due . ..... .I i .... ii i.itsizes and comparatively
small differences between baited sphere spacing in
the perimeter treatments versus the uniform or cluster
treatments. Future studies comparing the effective-
ness of imidacloprid-treated sphere deployment strat-
egies should be conducted within plantings known to
harbor residential populations of R. mendax, as well as
in plantings that are only infested seasonally by im-
migrant blueberry maggot flies. By conducting a com-
parison of residentially infested plots versus those that
receive immigrants only, it may be possible to gain
further insight into the importance of sphere deploy-
ment patterns for effective fruit protection. Also, fu-
ture studies must include larger scale treatment plots
before this technology can be recommended to grow-
ers as a possible substitute to conventional pesticide
applications.
During our second field season (2000), we found
that field-deployed, imidacloprid-treated spheres
were only slightly less effective than conventional
,, 1.. .i ... of a sprayed organophosphate (Guthion
50 W at 1.7 kg/ha) insecticide in providing fruit pro-
tection against R. mendax oviposition. We observed no
Si in fruit injury (oviposition scars) and only


Vol. 94, no. 4






STELINSKI AND LIBURD: STRATEGIES OF IMIDACLOPRID-TREATED SPHERES


a 0.9% .1lii.. .. in fruit infestation between plots
sprayed with Guthion and plots protected by imida-
cloprid-treated spheres. These results indicate that it
is : ,i i. to achieve fruit protection against R.
mendax. :- ;- I. i. equivalent to the level obtained
with broad-spectrum, organophosphate sprays in
highbush blueberries. However, the sphere density
used in our experiments to compare the various de-
ployment patterns was relatively high. At an estimated
cost of a $1.00 U.S. per sphere, commercial use of this
technology would necessitate a smaller number of
deployed spheres for this technology to be commer-
cially viable and comparable to insecticide treatments.
Future research must also focus on optimizing sphere
deployment densities and determining whether effec-
tive and economically viable densities can be
achieved.
Our monitoring program confirmed that blueberry
maggot fly activity in plots containing imidacloprid-
treated spheres was suppressed to a level similar to
that observed in plots that were treated with Guthion.
Similar suppression of fly activity has been recorded
with the apple maggot 11 foraging in areas where
imidacloprid-treated spheres were deployed (Liburd
et al. 1999 , .1 . et al. 2001). In a separate study,
Stelinski et al. (unpublished data) showed that imi-
dacloprid-treated spheres at 2% (AI) did not lose
their effectiveness in killing R. rmendax throughout
the duration of the 9-wk period when sexually mature
flies are ovipositing. We therefore suggest that a
single deployment of ammonium-baited, iridaclo-
prid-treated spheres could :. -. -.' I11 provide effec-
tive, season-long control of blueberry maggot :"i in
a commercial setting.
F,. :.;,. their effectiveness, the current version of
biodegradable spheres is ., .,,1i i. to rodent feed-
ing. We encountered this problem in 2000 and re-
placed -10% of our spheres 2 wk after initial de-
ployment. Future prototypes of insecticide-treated
spheres must be more resistant to rodent feeding if this
technology is to be effectively implemented as a con-
trol tactic for blueberry maggot flies. In addition, loss
of spheres due to rodent feeding may require periodic
replacements during the growing season.
This study documents that deployment of biode-
gradable, imidacloprid-treated spheres as a form of
behavioral control reduces R. mnendax infestation lev-
els below 1%. Although, such levels are still above the
currently mandated zero tolerance, we suggest that
even greater control can be achieved by making
spheres more attractive with effective and selective
baiting systems, further optimizing sphere deploy-
ment and density strategies, and perhaps making fruit
less attractive by coating it with visual or i, *
deterrents. Due to their t ;. 1 ::: ,,i and reduced
impact on the surrounding environment, imidaclo-
prid-treated spheres have potential for integration
into a second level IPM program (Prokopy et al. 1990)
by involving methods of cultural (Liburd et al 1998b)
and biological controls. Our study provides direct ev-
idence for the potential of using biodegradable


spheres treated with imidacloprid for control of blue-
berry maggot fly.


Acknowledgments
We are grateful to Dan Young for technical expertise and
assistance in both laboratory and field-based responsibilities.
Thanks to Kirsten Pelz for input during the preparation of
this manuscript. We express our gratitude to Katherine Pettit,
Erin Finn, and Caitlin Clements for assistance in fieldwork
and fruit collection. We also thank John Wise and the entire
staff of the Trevor Nichols Research Complex for their valu-
able assistance in pesticide spray applications and for pro-
viding us with fly rearing facilities. We appreciatively ac-
knowledge David Bloomberg of Fruitspheres Inc., Macomb,
IL, for providing us with biodegradable spheres to conduct
our research. This research was supported by the North
Central IPM Grant No. 61-4081.



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Received for publication 18 December 2000; accepted 27
March 2001.


Vol. 94, no. 4




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