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Effects of Four Chitin Synthesis Inhibitors on Feeding and Mortality of the Eastern Subterranean Termite, Reticulitermes flavipes Kollar (Isoptera: Rhinotermitidae)

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Baiting for termite population management has shown great potential. Studies have shown successful use of diflubenzuron and hexaflumuron in commercially available baiting systems. Both are chitin synthesis inhibitors in the benzoylphenyl urea cheimcial group. Other pesticides in this same chemi-cal grouping have shown activity against termites, but comparative research has been lacking. This study measured changes in feeding and mortality of the Eastern subterranean termite Reticulitermes flavipes when exposed to paper discs treated with one of four chitin synthesis inhibitors including; diflubenzuron, hexaflumuron, lufenuron, and triflumuron in laboratory tests. All were benzoylphenyl ureas, and tests included five different concentra-tions of each. Evidence of the "jackknifed" posture characteristic of chitin synthesis inhibition during eclosion when molting, overall mean survivor-ship, and survivorship through time were all observed. The results varied with chemical and concentration, but all treatments caused more mortality among termite populations than untreated controls. When presented with choices, R. flavipes did not show definitive preferences in a majority of the tests. Lufenuron was highly acceptable to R. flavipes, and caused high rates of mortality at all concentrations tested. Hexaflumuron and triflumuron showed similar acceptability and mortality at only two of the concentrations tested. Although diflubezuron was acceptable to the termites, mortality at six weeks post-exposure was significantly lower than with other chemicals tested.
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1
Eects of Four Chitin Synthesis Inhibitors on Feeding and
Mortality of the Eastern Subterranean Termite, Reticulitermes
avipes Kollar (Isoptera: Rhinotermitidae).
by
Rebecca D. Vahabzadeh1, Roger E. Gold1,2 & James W. Austin1
ABSTRACT
Baiting for termite population management has shown great potential.
Studies have shown successful use of diubenzuron and hexaumuron in
commercially available baiting systems. Both are chitin synthesis inhibitors in
the benzoylphenyl urea cheimcial group. Other pesticides in this same chemi-
cal grouping have shown activity against termites, but comparative research
has been lacking. is study measured changes in feeding and mortality of
the Eastern subterranean termite Reticulitermes avipes when exposed to
paper discs treated with one of four chitin synthesis inhibitors including;
diubenzuron, hexaumuron, lufenuron, and triumuron in laboratory tests.
All were benzoylphenyl ureas, and tests included ve dierent concentra-
tions of each. Evidence of the “jackknifed” posture characteristic of chitin
synthesis inhibition during eclosion when molting, overall mean survivor-
ship, and survivorship through time were all observed. e results varied
with chemical and concentration, but all treatments caused more mortality
among termite populations than untreated controls. When presented with
choices, R. avipes did not show denitive preferences in a majority of the
tests. Lufenuron was highly acceptable to R. avipes, and caused high rates of
mortality at all concentrations tested. Hexaumuron and triumuron showed
similar acceptability and mortality at only two of the concentrations tested.
Although diubezuron was acceptable to the termites, mortality at six weeks
post-exposure was signicantly lower than with other chemicals tested.
Keywords: Subterranean termites, Reticulitermes avipes Kollar, chitin
synthesis inhibitors, insect growth regulators, termite baiting systems.
1Center for Urban & Structural Entomology, Department of Entomology, Texas A&M University,
College Station, Texas, USA 77843-2143
2corresponding author. Email:r-gold@tamu.edu.
2 Sociobiology Vol. 50, No. 3, 2007
INTRODUCTION
Because of wide distribution, Reticulitermes avipes Kollar, the Eastern
subterranean termite, causes the most economic damage of any single termite
species in North America (Austin et al. 2005; Austin et al. 2006; Cornelius
and Osbrink 2001; Grace et al. 1989; Heintschel et al. 2006; Jones and LaFage
1980; Szalanski et al. 2003). ese termites usually need contact with the soil
in order to produce a successful colony, although some, including R. avipes,
are able to form aerial’ colonies with no soil contact if sucient moist condi-
tions exist (Su et al. 1989). Subterranean termites are found in virtually every
state in the United States with the exception of Alaska (Jones and LaFage
1980). Estimated costs associated with termite control and repair to urban
structures range from $2 billion (Gold et al. 1996) to $4 billion (NPMA
2004) in the United States, with global estimates exceeding $22 billion (Su
2002). Subterranean termites account for approximately 80% of this damage
(Su 1994). Reticulitermes avipes present a challenge to pest management
professionals (PMPs) and homeowners due to cryptic lifestyles. Homeown-
ers are oen only aware of the presence of these termites in their home when
the damage that they cause is signicant and the structural integrity of their
home is compromised. Most frequently, it is only aer the reproductive
caste is encountered (the alates), and then only during the swarming season
(Furman 2000). However, virtually all of the damage (to structural timbers)
is done by the foraging castes (Su 1994; Su and Scheran 2000), principally
known as workers or pseudergates.
Since the early 1940s, perimeter treatments using persistent soil-applied
pesticides have been to protect structures throughout the world. ese pe-
rimeter treatments have been eective, but when inconsistent applications
are made, even slight gaps in treatment areas may allow termites access to
vulnerable structures, especially when repellent termiticides are used (Kurica-
han and Gold 1998). A liquid chemical barrier to termites can be eective,
but concerns over environmental contamination with pesticides have raised
questions about the advisability of using this approach in the long term. For
this reason, pest management professionals (PMPs) have employed several
pre-construction options including the use of physical barriers, wood treat-
ments, and bait delivery systems which exploit the biological demands of
termites.
3
Vahabzadeh, R.D. et al.R.Flavipes mortality to CSIs
e use of termite baiting systems as a means of preventing and controlling
subterranean termite populations was initiated in 1967, and these technologies
have been extensively researched since that time (Esenther and Gray 1968;
Pawson and Gold 1996; Su and Scherahn 1996b; Haagsma and Bean 1998;
Kistner and Sbragia 2001; Ring et al. 2001; Tsundoa et al. 2001). e theory
behind using baits to control a termite population is that an entire colony
can be aected when a slow-acting, non-repellant chemical is distributed to
the colony by social interactions with the exposed foragers (Su et al. 1987).
ese social interactions include trophallaxis (stomodeal and proctodaeal),
allogrooming, and necrophagy.
Baits using Mirex were the rst to show success in the eld. Mirex baits
were found to eectively control Reticulitermes in Southern Mississippi, but
the United States Environmental Protection Agency (EPA) banned Mirex for
use in the United States (Esenther and Beal 1974, 1978). is led entomolo-
gists to look at other chemicals that would have potential for use in baits,
including chitin synthesis inhibitors (CSIs) (Esenther and Beal 1978; Dop-
pelreiter and Korioth 1981; Pawson and Gold 1996; Jones 1984; Ahmad et
al. 1986; Su and Scherahn 1991; Su and Scherahn 1993; Su et al., 1997;
Haagsma and Bean 1998; Grace and Su 2001; Kistner and Sbragia 2001; Su
et al. 2001; Tsunoda et al. 2001).
CSIs are a category of insect growth regulators that interfere with the
assembly of chitin aer a molt (Pedigo 1996). e four chemicals that
were used in this study belong to the chemical group called benzoylphenyl
ureas (BPUs) (Fig. 1). We use BPUs and chitin synthesis inhibitors (CSIs)
interchangeably throughout the paper, but their subtle dierences should
be noted, as described herein. e exact mode of action of BPUs is not fully
understood; however, it is known that BPUs do not inhibit chitin synthetase,
the enzyme controlling the last step of the process, but rather seem to interfere
with the assembly of chitin chains and microbrils. When immature stages
of insects are exposed to BPUs, they are incapable of completing ecdysis. As a
consequence, termites die during the molting process (Graf 1999). BPUs are
highly lipophilic molecules, and when administered to the host, they tend to
deposit in the body fat, where they are slowly released into the blood stream.
is mechanism is complemented by the fact that only a small amount of the
molecule is metabolized. A high percentage of the excretion of these chemicals
4 Sociobiology Vol. 50, No. 3, 2007
occurs in the form of the unchanged parent molecule. Because of this trait,
a natural slow release occurs that prolongs the bioavailability of these com-
pounds (Graf 1999). is slow action makes BPUs very good candidates for
Fig. 1. BPUs: A) Diubenzuron, B) Hexaumuron, C) Lufenuron, and D) Triumuron.
5
Vahabzadeh, R.D. et al.R.Flavipes mortality to CSIs
use in baits. Currently in the United States, hexaumuron, novaumuron and
diubenzuron are incorporated into commercially available baiting systems,
while triumuron is still being developed for use against termites. Lufenuron
is approved for use, but ecacy testing for termite control is still underway.
Of the four benzoylphenyl ureas tested in this project (Fig 1), the rst to
be introduced was diubenzuron [1-(4-cholorophenyl)-3-(2,6-diubenzoyl)
urea)]. Diubenzuron was rst reported in the literature by J.J. van Daalen
in 1972, and is now produced by Solvay Duphar B.V. (Tomlin 2000). It is
currently the active ingredient in Exterra™ Termite Interception and Baiting
System marketed by Ensystex Inc., and Advance Termite Bait System TM
by Whitmire Micro-Gen. Doppelreiter and Korioth (1981) reported that
diubenzuron caused mortality in R. avipes at between 10 and 1000 ppm
with the concentration dierence being insignicant. Ahmad et al. (1986)
showed that diubenzuron not only caused mortality in termites, but also
reduced fecundity of female termites, and eected viability of eggs. Su and
Scheran (1993) reported that R. avipes showed high mortality (80 %)
when exposed to diubenzuron in treated diet. While Ahmad et al. (1986)
showed that termites would accept the diet at up to 1000 ppm diubenzuron,
Su and Scheran (1993) stated that termites were deterred from feeding on
diubenzuron when concentrations were above 31.3 ppm.
Triumuron [1-(2-cholorobenzoyl)-3-(4-triuoromethoxyphenyl) urea]
was rst reported in the literature by G. Zoebelein et al. in 1979 and is produced
by Bayer Environmental Science® (Tomlin 2000). Triumuron has been used
on a variety of dierent pests and has both larvicidal and ovicidal activity. It
has shown eects on stored product beetles (Blumberg et al. 1985; Elek and
Longsta 1994), rice weevils (Smith and Grigarick 1989), ies (Broce and
Gonzaga 1987; Knapp and Cilek 1988), spiny bollworm (Meisner 1987),
cockroaches (Demark and Bennett 1989), scale insects (Eisa et al. 1991),
and locusts (Wilps and Diop 1997). It is currently registered for use in crop
protection, public health and animal health usage. At the present time, it is
reportedly registered for termite control in Australia.
Hexaumuron (1[3,5-dichloro-4-(1,1,2,2-tetrauoroethoxy) phenyl]-3-
(2,6-diurobenzoyl) urea) was rst reported in the literature by R.J. Sbragia
et al. in 1983 and introduced by Dow Elanco (now DowAgroSciences) in
1987 (Tomlin 2000). It is currently the active ingredient in Sentricon® Bait-
Reference not in bibliography
6 Sociobiology Vol. 50, No. 3, 2007
ing Systems. Hexaumuron has been shown to have eects on subterranean
termites both in the laboratory and in the eld (Pawson and Gold 1996;
Haagsma and Bean 1998; Peters and Fitzgerald 1999; Prabhakaran 2001;
Su 1994; Su et al. 1997, 2001). Hexaumuron has also been shown to have
potential to control fungus growing ants (Peppuy et al.1998). Hexaumuron
has been reported to be a superior to lufenuron and diubenzuron by Su and
Scheran (1993, 1996a) for use in termite baiting systems.
Lufenuron [(RS)-1-[2,5-dichloro-4-(1,1,2,3,3,3-hexauroropropoxy)
phenyl]-3-(2,6-diurorobenzoyl) urea] was rst reported in 1989 and intro-
duced by Ciba-Geigy (now Syngenta Crop Protection, Inc.) in 1990 (Tomlin
2000). Lufenuron has been shown to greatly reduced egg hatch in cat eas
by eecting the composition of the chorion of the egg (Meola et al. 1999).
Lufenuron is also used to control Lepidoptera and Coleoptera larvae on cot-
ton, maize, and vegetables, as well as citrus whiteies and rust mites on citrus
fruit (Tomlin 2000). It has been registered as Zyrox® for termite control.
MATERIALS AND METHODS
Termite Collection
All Reticulitermes avipes used for these experiments were collected
from colonies in College Station, Texas. ey were collected using traps of
moistened corrugated cardboard housed in polyvinylchloride (PVC) pipes
that were12.5 cm tall with a 10 cm diameter. Aer being sorted in the labo-
ratory, the termites were maintained in Falcon 150 x 25mm sterile plastic
petri dishes and supplied with Fisher brand tongue depressors for food and
shelter. Termites used in the experiments were held in the laboratory for less
than one month.
Bait Preparation
e chemical solutions containing the benzoylphenyl ureas were all pre-
pared with high performance liquid chromatograph grade acetone from EM
Science. A solution of each of the four BPUs at 1000 ppm were prepared,
and then serial (1:10) dilutions were made to yield 100, 10, 1, and 0.1 ppm
solutions, respectively. Hexaumuron, diubenzuron and triumuron were
all obtained from Chem Services (West Chester, PA) and were 99% pure.
Lufenuron was obtained from Sigma Chemical (St. Louis, MO) and was
7
Vahabzadeh, R.D. et al.R.Flavipes mortality to CSIs
99.7% pure.
Termite Feeding Substrates.
A 4 x 6 cm piece of one-ply BayWest 1002 paper was soaked in the treated
solution in a 100 x 20mm Kimax® dish. Non-treated controls were prepared
with the same paper stock which was either soaked in pure acetone, to test
for acetone eects (acetone controls), or put into the dish without any treat-
ment (untreated controls). e treated papers were then held horizontally
and sequentially rotated until dry to minimize a dierential concentration
gradient of the chemical from one end of the paper. e paper was then placed
in the lid portion of a Fisher brand 100 x 15mm sterile plastic petri dish and
placed in a ‘humidity dish’. Humidity dishes were constructed to keep the
environment at 100% RH to optimize feeding by the termites. e humidity
chambers were made of a Falcon 150 x 25mm sterile plastic petri dishes in which
approximately 40 g of sand was spread evenly on the bottom and moistened
thoroughly. e dishes containing the paper were then put on the sand and
the lid of the larger dish was put in place. is procedure was repeated three
times for each concentration of the four chemicals in evaluation.
Termite Feeding Trials.
To initiate a feeding trial, 300 worker termites were aspirated and placed
in a 100 x 15 mm sterile plastic petri dish and held in the humidity dish.
A dish of 300 termites was prepared for each of the concentrations of the
BPUs to be tested. Both of the dishes containing the paper and the termites
were allowed to sit for 24 h prior to testing. is allowed the treated paper
to moisten in the humid environment without direct application of water,
making it more acceptable to feeding termites, and to prevent dierential
concentration gradients of the chemical to the edges of the paper. During this
period, the termites were also starved. Aer 24 h, the termites were split into
groups of 100 and placed into the dishes with the treated papers or controls.
Each concentration-chemical group had termites from the same colony. e
termites were allowed to feed on the paper for 5 d, aer which time they were
removed and placed into clean petri dishes for evaluation of survivorship.
e treated paper was le in the dish, and the bottom portion of the dish
was placed on it to keep the paper in place. e area of the papers remaining
were then determined. Area loss measurements were done by analyzing digital
8 Sociobiology Vol. 50, No. 3, 2007
images taken of each paper before and aer testing, similar to the procedures
of Su and Messenger (2000), Vahabzadeh (2002) and Heintschel et al. (2007)
Photographs were taken with a digital camera (Nikon Coolpix® 4300, Tokyo,
Japan). All images were incorporated into Adobe Photoshop (Adobe Systems
Inc. 2001) where they were converted to a black-and-white color scheme to
increase measurement accuracy. is required translating the images’ color
to grayscale and setting the contrast to a maximum level. An electronic paint
tool was used to correct small blemishes that remained inside the perimeter
of the paper aer the color conversion with Adobe Photoshop soware
(Adobe Systems, San Jose, California). e amended images were analyzed
using SigmaScan® Pro 5 (SPSS Inc. 1999) to determine the area remaining
of each paper. is area remaining following feeding was then subtracted
from the original known area of the paper to estimate the amount of paper
consumed by the termites.
Survivorship Experiments.
Aer being removed from the treatment dishes, 100 termites were placed
in a 100 x 15 mm petri dish with a smaller version of the tongue depressor
structure used to house freshly collected termites in our laboratory. Su and
Scheran (1993) reported the “symptoms of ecdysis inhibition” as cannibal-
ization of appendages and antennae by nest mates, as well as the “jackknifed”
position. In this study, both the number of surviving termites, and the number
that showed the jackknifed pose were recorded as evidence of chitin synthesis
inhibition. e numbers of surviving termites were recorded on a weekly
basis for six wks beginning at 1 wk aer placement on non-treated food (12
d post-exposure). Experimental units were maintained in an Elliot-Williams
Environmental chamber held at 24 ± 2°C and 24h D:D. A Hobo Pro Series
monitor was placed in the chamber to record temperature and humidity.
Choice Tests.
Choice tests were carried out in Falcon 150 x 25 mm sterile plastic petri
dishes. e cellulose sources used were discs (7 mm dia.) of Fisherbrand
Qualitative P5 Filter paper cut with a standard hole-punch out. Past projects
done in our laboratory showed that R. avipes would feed on this paper. e
discs were soaked in either 0.1, 1, 10, 100, or 1000 ppm solutions of diuben-
zuron, hexaumuron, lufenuron or triumeron, respectively. e control
9
Vahabzadeh, R.D. et al.R.Flavipes mortality to CSIs
discs were not treated, but were handled just as the treated discs. For each
test, two discs, each treated with a dierent BPU of the same concentration,
or a non-treated control were place at equal distance from the center of the
dish. e termites were given only two choices based on preliminary experi-
ments that found that termites seemed to be ‘overwhelmed’ when presented
more than two choices, and hovering in the center of the dish, not visiting
any of the choices. e clear dishes were labeled on the bottom so that the
circles could be identied through the translucent dish without marking on
the actual paper disc. e discs were moistened with 25µl of water and 50
R. avipes workers were aspirated and placed in the center of the dish. Aer
giving the termites at least one hour to ‘acclimate’, the number of termites
at each disc were counted every hour for 6 h on the rst day (24 h). On the
second day, the termites were counted once in the morning and once in
the late aernoon. e termites were counted once in the aernoon of the
third day. Aer the initial day, the paper circles were moistened twice a day.
Termites on the edge of the disc were counted as feeding on the paper. Every
possible pair-wise combination of the four CSIs and the non-treated control
were tested. Between observations, the dishes were kept in large sealed plastic
containers with moist sand in the bottom so as to maintain 100% RH.
Voucher Information.
Vouchers of the termites used in these studies were placed in the Depart-
ment of Entomology, Texas A&M University Insect Collection, in the Minnie
Belle Heep Building, College Station, TX.
RESULTS
Subterranean Termite Feeding.
Tests for signicant dierences and interaction eects were conducted
applying an analysis of variance (ANOVA) (SPSS 2001). Signicant dier-
ences among survivors were detected for day (F = 129.44, df =5, p < 0.001),
Treatment (F = 48.907, df =4, p < 0.001), Concentration (F = 31.815, df
=4, p < 0.001), Treatment x Concentration (F = 20.565, df =12, p < 0.001),
and Day x Treatment (F = 3.014, df =25, p < 0.001). Post Hoc tests for means
comparisons were performed applying Tukey’s highly signicant dierence
(HSD) at the α = 0.05 level. Reticulitermes avipes fed on all of the treated
10 Sociobiology Vol. 50, No. 3, 2007
and control papers, and the amount of feeding varied depending on chemical
and concentration used in the treatments. Termites consumed signicantly
(p< 0.001) more of the paper treated with diubenzuron at concentrations
ranging from 0.1-100 ppm (39.92-52.38 % of the paper consumed) than at
1000 ppm (29.58%) (Table 1). e lower concentrations (0.1-100 ppm) were
also favored over either control (15.99 and 14.52% for acetone and untreated
paper control, respectively, versus 10.55 to 14.42% of the mean area remain-
ing), implicating a non deterrence for the chemical treatments.
e consumption of triumuron-treated paper showed a similar trend to
diubenzuron. Of the concentrations tested, the termites consumed more
of the paper treated with 10 and 100 ppm solutions (53.92 and 55.00%,
respectively), but signicantly less (p<0.001) in controls (33.38 acetone and
39.50% paper control, respectively). ere is a direct relationship between
the mean area remaining (cm2) and the percent of paper consumed with
increased consumption and increased dosage up to 100 ppm. e percent
paper consumed ranged from 44.54 to 55.00%. e mean area remaining
ranged from 10.80 to14.52 cm2, whereas the highest dosage of 1000 ppm
was only 41.12% paper consumed and 14.13 cm2 area remaining. e results
from the hexaumuron trials are summarized in Table 1. ere was a sig-
nicant (p<0.001) dierence in the amount of treated paper consumed at
concentrations of 1-1000 ppm as compared to the two control and the 0.1
ppm treatments. e most preferred concentration was 1 ppm where 60.25
% of the test papers were consumed within 5 d.
Lufenuron at concentrations of 0.1-1000 were signicantly (p<0.001) dif-
ferent, in terms of consumption of treated papers by R. avipes as compared
to either control (Table 1). Of the concentrations evaluated, 0.1 and 1.0 ppm
were favored over the other concentrations, results support the attractiveness
of lufenuron to foraging termites.
Survivorship - Mean Survivorship.
All of the test populations of R. avipes showed mortality through the six
weeks of observations. e mean survivorship at the end of the six week period
was compared between the groups over time and was evaluated by ANOVA
(SPSS, 2001). Termites were counted each week for six weeks in order to
calculate the slope of the percentage of survivors for each active ingredient
11
Vahabzadeh, R.D. et al.R.Flavipes mortality to CSIs
Table 1. Mean percent of test papers (24 cm2) treated with diubenzuron, triumuron, hexaumuron and lufenuron consumed by Reticulitermes avipes
at the concentrations indicated using digital analysis of the mean areas remaining following feeding for 5 days.
Concentration (ppm) Diubenzuron Triubenzuron Hexaumuron Lufenuron
Mean Area1 % of paper Mean Area1 % of paper Mean Area1 % of paper Mean Area1 % of paper
Remaining (cm2) consumed Remaining (cm2) consumed Remaining (cm2) consumed Remaining (cm2) consumed
Acetone control 15.99+ 0.68 a 33.38 15.99+0.68 a 33.38 15.99+0.68 a 33.38 15.99+0.68 a 33.38
paper control 14.52+1.19 ab 39.50 14.52+1.19 ab 39.50 14.52+1.19 ab 39.50 14.52+1.19 ab 39.50
0.1 11.43+2.80 c 52.38 13.31+0.40 bc 44.54 15.72+0.97 ab 34.50 5.74+0.75 c 76.08
1 10.55+2.36 c 56.04 12.56+0.50 bc 47.67 9.54+0.92 c 60.25 5.99+0.94 c 75.04
10 12.29+1.11 bcd 48.79 11.06+0.72 cde 53.92 12.78+2.22 b 46.75 9.65+1.48 d 59.79
100 14.42+2.26 abd 39.92 10.80+0.77 de 55.00 10.19+1.74 c 57.54 9.81+0.39 d 59.13
1000 16.90+0.13 e 29.58 14.13+0.61 abc 41.12 12.02+2.99 b 49.92 11.91+0.88 e 50.38
1Means within columns followed by the same letter were not signicantly dierent from each other applying Tukey’s HSD at the α = 0.05 level (SPSS, 2001).
12 Sociobiology Vol. 50, No. 3, 2007
and concentration. is was performed by calculating the slope of the best t
line of the means of survivors using linear regression and comparing means
by ANOVA (SPSS 2001).
Diubenzuron - e slopes of the percentage of survivors for the termites
fed on diubenzuron-treated paper were variable. e termites fed on paper
treated with 10 ppm diubenzuron solution died signicantly (p<0.001)
slower than the termites fed on the other treated papers (Figure 2).
Triumuron - All but one concentration had a signicantly dierent slope
than the acetone control (Table 2); however none were signicantly dierent
from the untreated control group (Figure 2).
Hexaumuron - ere was no signicant dierence between the treated
groups and those fed on untreated paper (Figure 2). ere was a signicant
dierence (p<0.001) among two of the groups and the acetone control. Of
the treated groups, the termites fed on paper treated with 0.1 ppm solution
Fig. 2. Survival of R. avipes to controls (acetone and paper) and four BPUs: Diubenzeron,
Hexaumuron, Lufenuron, and Triumuron at A) 12 DAT, B) 17 DAT, C) 24 DAT, D) 31 DAT,
E) 38 DAT, and F) 45 DAT. e x-axis denotes BPU concentrations ranging from 0.1 to 1000
ppm, y-axis denotes active ingredient and/or control, and z-axis denotes percent survival (n=100),
respectively.
13
Vahabzadeh, R.D. et al.R.Flavipes mortality to CSIs
died the slowest.
Lufenuron - All of the termites fed on
paper treated with lufenuron died sig-
nicantly (p<0.001) faster than termites
fed on either controls. ese results are
summarized in Figure 2.
DISCUSSION
e rst objective of this study was to
determine the concentration of each of
the four BPUs that was the most accept-
able to Reticulitermes avipes. Although
a specic ‘threshold’ concentration was
not observed, it is apparent that R. avipes
will adjust to the amount of feeding on
a treated food source depending on the
concentration of the treatments. ere
were signicant dierences in amount of
feeding not only among the four BPUs,
but also among dierent concentrations
of the same BPU. Lufenuron was highly
acceptable to R. avipes at four of the ve
concentrations tested. is BPU treated
disc was the most consumed by R. avi-
pes in this portion of the experiment. Su
and Scheran (1996a) report lufenuron
to be less acceptable to R. avipes than
hexaumuron. In their study, lufenuron
was found deterrent at 0.4% of the con-
centration at which hexaumuron was
found deterrent. In the present study,
hexaumuron at 1 and 100 ppm had
similar acceptability to lufenuron, while
the other four concentrations tested were
generally less acceptable (to R. avipes).
Table 2. Mean slopes of the percentage of survivors over a six week period challenged to various active ingredients.
Chitin Synthesis Inhibitor
Concentration Diubenzuron Triubenzuron Hexaumuron lufenuron
(ppm) Slope/intercept R2 Slope/intercept R2 Slope/intercept R2 Slope/intercept R2
Acetone control y = -1.2893x + 107.94a 0.9407 y = -1.2893x + 107.94a 0.9407 y = -1.2893x + 107.94a 0.9407 y = -1.2893x + 107.94a 0.9407
paper control y = -1.6974x + 109.52ab 0.9356 y = -1.6974x + 109.52ab 0.9356 y = -1.6974x + 109.52ab 0.9356 y = -1.6974x + 109.52ab 0.9356
0.1 y = -2.2143x + 104.5c 0.9433 y = -1.5854x + 70.349bc 0.9479 y = -1.8493x + 102.60bc 0.9502 y = -2.5255x + 121.02c 0.9909
1 y = -1.7175x + 98.193bc 0.9571 y = -1.2253x + 73.771abcd 0.8960 y = -2.4513x + 116.01cd 0.9725 y = -2.5770x + 120.06cd 0.9856
10 y = -0.9147x + 100.07ad 0.9503 y = -1.3666x + 68.593bcde 0.8886 y = -2.5664x + 110.82cde 0.9345 y = -2.2408x + 106.92cde 0.9659
100 y = -1.4943x + 97.481abd 0.9743 y = -1.6974x + 109.52abdf 0.9356 y = -2.2786x + 102.42df 0.9342 y = -2.0650x + 82.586cdef 0.9157
1000 y = -1.4540x + 86.302abc 0.7226 y = -1.7415x + 76.222bcde 0.9306 y = -2.4912x + 100.56cde 0.8957 y = -0.0133x + 0.4826ab 0.3804
1Means within columns followed by the same letter were not signicantly dierent from each other applying Tukey’s HSD at the α = 0.05 level (SPSS, 2001).
14 Sociobiology Vol. 50, No. 3, 2007
Diubenzuron at 0.1 and 1 ppm and triumuron at 10 and 100 ppm also
had similar acceptability to those of hexaumuron at 100 ppm for R. avi-
pes. ese dierences may be attributed to subtle dierences among colony
preference for either a cellulose food source or the active ingredients applied
to them in the present study or in the study by Su and Scherahn (1996a).
Acceptance of diubenzuron and hexaumuron bait products from eld
studies have been comparable for both rhinotermitid groups in Texas (JWA,
personal observation).
Feeding: Amount of Paper Consumed
e amount of treated material that R. avipes will consume is an indication
of how acceptable that treated material is to the test termite population. e
results of this test indicate that R. avipes will feed on BPU-treated material
depending on the CSI and the concentration at which it was treated.
Survivorship: Mean percentage of survivors
e goal of any termite baiting treatment is to ultimately reduce the colony
to a point where it is not causing signicant damage to a structure or to elimi-
nate it completely. Observing the mean percentage of survivors of R. avipes
45 d aer being exposed to four CSIs at ve dierent concentrations allowed
us to conclude that these chemicals have an adverse eect on termite survival.
ese results were concentration dependent and quite variable (Fig. 2).
e optimal CSI concentration incorporated into a bait would kill slowly
enough for the foragers to transfer the treated material to its colony mates.
us it is not only important to look at overall mean percentage of survivors,
but also the rate at which the termites died. A chemical that kills too quickly
would not be eective as a termite bait tool; however, in these tests even low
concentrations produced eects in one to two weeks. Although this should
be sucient time for termites to move the CSI into the colony, the rate of
transfer can depend largely on the size, age, and nesting structure of a colony.
While a slow-acting chemical is optimal, it must cause mortality within the
population within a reasonable period of time in order to prevent extensive
damage to the structure.
e second object was to determine if feeding on diet treated with these
four BPUs would have an eect on R. avipes. Termites exposed to diets
treated with all four BPUs exhibited characteristic jackknifed postures as-
15
Vahabzadeh, R.D. et al.R.Flavipes mortality to CSIs
sociated with death from chitin synthesis inhibition. Many also showed
dierent survivorship and rates of mortality from untreated control groups.
Once again, there was variation among the four BPUs, and within dier-
ent concentrations of the same BPUs; however lufenuron caused the most
mortality in the test period under the constraints of this experiment. Four
of the ve lufenuron concentrations tested caused at least 90% mortality in
approximately 7 weeks of this experiment (Fig. 2). Similarly, hexaumuron
elicited at least 90% mortality with three of its concentrations, followed by
triumuron with two of the concentrations tested. ese results dier from Su
and Scherans 1996 ndings that non-deterrent concentrations of lufenuron
caused less than 80% mortality even aer 9 weeks. e reason for these dif-
ferences remains unknown. One can only speculate that subtle dierences
among various natural populations of termites collected from the eld would
likely inuence their respective susceptibilities to these BPUs.
Eects of Benzoylphenyl Ureas: Jackkning
Although a specic mode of action for chitin synthesis inhibitors in un-
known, their eects can be observed. Termites fed on all four of the BPUs
used in this experiment showed the jackknifed posture, which indicated that
death would occur due to BPU exposure. e frequency of jackkning, like
the other observations in these experiments, was dependent on the chemical
and concentration.
e third objective of this study was to determine if R. avipes would
exhibit a preference for dierent treatments of BPUs or untreated controls.
ere were some preferences evident. e majority of the choice tests showed
no preference between the four BPUs represented. When compared to con-
trols, diubenzuron was the only BPU chosen more oen than an untreated
control, and that was in only one concentration tested. is would indicate
that in a setting in which BPUs are incorporated into termite baits and placed
around a structure, there is an equal chance that R. avipes would visit an
untreated food source as there is a chance that it would visit the bait. Even
though colonies of R. avipes can be highly localized in conned urban settings
where the frequency of interaction between adjacent foraging populations
would be expected high, the directed foraging of termites to bait stations
can be relatively low (Vargo 2003). Many variables, such as seasonal weather
16 Sociobiology Vol. 50, No. 3, 2007
patterns, predation, competition between nearby colonies, size or age of a
colony, and the number of alternative food sources available can aect the
viability of a termite colony and confound the interpretation of the action
of the bait (Forschler and Ryder 1996a, 1996b).
Choice Tests
Both choice and no-choice tests were conducted with R. avipes to treated
paper. When the treated materials were presented to groups of termites, the
termites oen showed no preference, when observing the number of termites
visiting discs at set intervals. But also observed were the number of discs that
were completely consumed at the end of the experiment. In only seven of the
30 choice tests between treated discs did R. avipes show a preference for
one treatment over another.
Around a structure R. avipes will probably not be given a choice between
two dierent commercial baits. ey will however be presented with the choice
of feeding on a treated bait and untreated materials, namely the structure
that is supposedly being protected by the bait. In the choice tests in which
the termites had a choice between a treated disc and an untreated control
R. avipes showed a preference in eight of 20, respectively. A breakdown of
their feeding preferences follows:
Diubenzuron
Reticulitermes avipes consumed more of the paper treated with lower
concentrations (0.1 - 10 ppm), with the 1 ppm solution being the most
acceptable. At the higher concentrations, 100 and 1000 ppm, feeding was
inhibited. It is apparent that there might be slight attractiveness at concentra-
tions between 1 and 10 ppm. ere was a signicant dierence in percentage
of survivors depending on concentration. is is contrary to the ndings of
Dopplereiter and Korith (1981) who observed no signicant concentration
related dierences in production of mortality in R. avipes.
R. avipes fed on diubenzuron-treated paper had some of the highest
percentages of survivors in the portion of the experiment. Four of the ve
concentrations had similar survivorship percentages as the untreated controls.
Termite feeding on 10 ppm treated discs with diubenzuron had the highest
mean percentage of survivors in the entire experiment (~ 61%), even outnum-
bering the survivors in the controls, 44 and 26 % for acetone and untreated
17
Vahabzadeh, R.D. et al.R.Flavipes mortality to CSIs
paper controls, respectively. R. avipes fed on diubenzuron-treated paper had
some of the slowest mortality, similar to the untreated controls; however, the
eects of diubenzuron may take longer to observe than 6 weeks as suggested
by Dopplereiter and Korioth (1981). ey observed 100% aer 14 weeks of
observation. Although jackknifed termites were observed, diubenzuron had
fewer jackknifed termites when compared to lufenuron and triumuron at
the same concentrations and time. e majority of this jackkning occurred
at the higher concentrations; however, feeding decreased above 10 ppm. is
suggests a threshold of preference which is concentration-dependent.
Diubenzuron was preferred over triumuron at 10 ppm while the opposite
was true at 100 ppm. Interestingly enough, in the 10 ppm choice test, more
triumuron discs were consumed and the opposite was true in the 100 ppm
choice test. Although there was no signicant dierence in the number of
termites visiting the discs treated with 1000 ppm dilutions, there were two
discs of diubenzuron completely consumed while no visible consumption
of triumuron discs were observed. is would imply that R avipes, given
a choice, prefers diubenzuron to triumuron at 10, 100 and 1000 ppm.
ere was no dierence in preference for diubenzuron when compared to
lufenuron; with about the same number of discs completely consumed of
each (Figure 2).
When the termites had a choice between hexaumuron and diubenzuron,
they showed a preference in two of the tests. At 1 ppm, the termites visited the
hexaumuron discs more oen, which was supported by the fact that two of
the hexaumuron discs were completely consumed while only one diuben-
zuron disc was completely consumed. At 10 ppm the diubenzuron-treated
discs were visited more oen and both chemicals had one disc completely
gone. Although at 100 ppm, the number of termites visiting discs of each
BPU were exactly the same, at two hexaumuron discs.
Diubenzuron-treated discs were visited more oen than the control at
both 1 and 10 ppm. When the disc was treated with 1000 ppm, the termites
visited the control disc more oen. is was the only test in which the number
of discs consumed were noticeably dierent, with seven diubenzuron discs
completely consumed as compared to four of the controls were completely
consumed.
Diubenzuron had a moderately positive correlation between concentra-
18 Sociobiology Vol. 50, No. 3, 2007
tion and amount of feeding (R2 = 0.764). is implies a general trend for
R.avipes to be less attracted to treated discs as concentration or diuben-
zuron increased. is could be a disadvantage to this CSI when attempting
to formulate an active concentration range that would be amenable to most
target termite species.
Triumuron
When fed to R. avipes, triumuron treated disc preference were dierent
to diubenzuron treatments. Ten and 100 ppm solutions of triumuron were
the most acceptable to R. avipes, while the other three concentrations of
triumuron were less attractive. Termites fed on triumuron-treated paper
exhibited variability in mean percentage of survivors (ranging from 0.50 –
37.33%). Termites fed on paper treated with 0.1 and 1000 ppm solutions
of triumuron had very low mean percentage of survivors (5.0 and 0.50%,
respectively), while termites fed on 100 ppm solution had a high percentage
of survivors (37.33%). It is unclear if these results simply demonstrate the
lack of preference to this active ingredient-concentration in terms of feeding
or possible aversion, which subsequently resulted with the higher percentage
of survivors.
In the triumuron trials, most of the concentrations showed a slope for
mortality that was signicantly dierent from controls (Table 2), indicating
some level of eectiveness. Triumuron at 0.1 ppm showed mortality, but
the mean percentage of survivors at the beginning of the experiment was ~
40% while the three remaining concentrations had initial survivorship ~
60%. A higher initial survivorship could allow more foragers to return to
the colony and potentially transfer the treated material to other termites.
Conversely, a higher survivorship may reect greater aversion to the various
treatment combinations. Reticulitermes avipes that were fed on paper treated
with triumuron exhibited the most jackkning compared to the other three
BPUs in this experiment. e majority of this jackkning was observed in
termites feeding on paper treated with 1 and 10 ppm solutions. is implies
that this chemical may be an eective bait active ingredient at low to moder-
ate concentrations. R. avipes showed a preference for hexaumuron paper
discs treated at1000 ppm when given a choice between hexaumuron and
triumuron. It was observed that overall eight hexaumuron discs were
19
Vahabzadeh, R.D. et al.R.Flavipes mortality to CSIs
consumed while only one triumuron disc was completely consumed for the
same concentration (1000 ppm).
Only one choice test between triumuron and lufenuron showed a dif-
ference in the number of termites visiting discs. At 100 ppm, the termites
visited the lufenuron-treated disc more oen. Seven discs of triumuron
were completely consumed at the end of the experiment while only three of
lufenuron were completely consumed. ree tests were signicantly dierent
(p < 0.0001) in the choice between triumuron and the untreated control:
Triumuron was preferred at 1 and 100 ppm while the control was more read-
ily frequented at 10 ppm. Although inconclusive, these results suggest that
triumuron at 1 and 100 ppm could be good candidates to further evaluate
for use in termite baiting situations around structures. Other than the strong
positive correlations between mean percentage of survivors and the slope
(R2=0.979), triumuron showed no specic trends among the measured
factors in this experiment.
Hexaumuron
e results of the hexaumuron trials were variable and did not show
a denite pattern with relation to the amount of feeding. e most ac-
ceptable concentrations of hexaumuron were at 1 and 100 ppm. Overall,
hexaumuron caused mortality that was signicantly dierent (p < 0.0001)
than the untreated control groups at 10, 100 and 1000 ppm. Termites fed
on hexaumuron-treated paper had high initial percentages of survivors (~
80%), and all but one concentration (0.1 ppm) showed a slope signicantly
more negative than that of the controls (Table 2). Similar to our ndings,
Sheets et al. (2000) demonstrated that the rate of uptake, level of maximum
uptake, and amount of insect-to-insect transfer were concentration depen-
dent for hexaumuron, and that even aer 40 d exposure it was not further
metabolized, thus demonstrating the ability to spread throughout a termite
colony in an ecacious manner.
R. avipes challenged with hexaumuron treated paper were observed
to exhibit jackkning trends similar to diubenzuron; however, there was
less jackkning than in the termites fed on triumuron or lufenuron at the
same concentrations over the same period of time (Fig. 2). e majority of
the jackkning observed in hexaumuron baited termites were observed
20 Sociobiology Vol. 50, No. 3, 2007
among the higher concentrations. ere was only one choice test in which
the termites showed a preference between hexaumuron and lufenuron. At
1000 ppm, more termites were observed at the hexaumuron-treated discs.
is suggests that even at high concentrations of hexaumuron, termites
will continue to feed and consume treated cellulose materials, one possible
explanation as to why it was selected as the BPU of choice among the earli-
est bait systems on the market. Further evaluation of this BPU with other
active ingredients resulted with an equal number of discs being consumed.
In only one test between hexaumuron and the untreated control did the
termites exhibit any preference. At 10 ppm, the control was preferred to the
hexaumuron-treated disc. As with triumuron, the only strong correlation
(R2=0.962) in hexaumuron was between the mean percent of survivors and
its slope (Table 2).
Lufenuron
Lufenuron was the most palatable of the chemicals evaluated. Four of
the six most highly consumed disc areas remaining were lufenuron treated
papers. Results suggested by the quantity of paper consumed by R. avipes
in this portion of the experiment imply that lufenuron was a highly accept-
able BPU at most concentrations tested. Termites that fed on paper treated
with 1000 ppm dilutions of lufenuron had no survivors within the rst two
weeks of the six week observation period, while most of the other CSIs and
controls had surviving termites well into the six week observation period. It is
unclear if rapid death was due to direct toxicity or if chitin inhibition played
a more signicant role, particularly in instances where internal gut morphol-
ogy may have been aected. e other three concentrations of lufenuron
had similar mean percentages of survivors; these being fairly low relative to
other CSIs. e slopes of survivors for termites that fed on lufenuron-treated
paper exhibited some variability. Termites fed on 0.1, 1 and 10 ppm dilutions
of lufenuron had initial survivorship ~ 90%, and had consistently negative
slopes for survivorship (Table 2), indicating that most termites would likely
die between 55 and 60 days, just a few days aer the hexaumuron treated
termites. Termites that were fed on lufenuron treated discs at 100 ppm had
a lower initial survivorship (~ 60%), and were all dead aer four weeks of
observations. As stated before, most termites exposed to lufenuron at 1000
21
Vahabzadeh, R.D. et al.R.Flavipes mortality to CSIs
ppm were dead upon the initial observation period. R. avipes that fed on
paper treated with lufenuron exhibited jackkning postures, although not as
frequently as with triumuron. Like triumuron, their jackkning postures
were observed in termites which fed more readily at lower concentrations,
which ate more, and died more slowly than the two highest concentrations
applied. Some death without observable jackning postures may be due to
internal damage elicited by BPUs.
Chitin synthesis inhibitors have been demonstrated to aect the produc-
tion of the peritrophic membrane of locust Locusta migratoria (L.) (Clarke
et al. 1977), blow y Calliphora erythrocephala Meigen (Becker 1978), and
both the pupal integument of yellow mealworm, Tenebrio molitor L. (Soltani
1987) and its developing peritrophic membrane (Soltani 1984). It may also
be that R. avipes possess a less sensitive target site for lufenurons mode of
action (Bogwitz et al. 2005), resulting in more rapid toxicity and death. It
is well established that dierent organisms possess variable proportions of
muscarinergic receptors, which invariably inuence insects dierently when
challenged to dierent insecticides (Liu & Casida 1993) and likely with
most BPUs. Even when overt jackning is not observed, internal damage to
various sights is occurring. Morales-Ramos et al. (2006) support this notion
and have demonstrated that BPUs consumed by termites damage peritrophic
matrices, sometimes preventing their full development.
In only one test between lufenuron and the untreated controls did ter-
mites demonstrate a preference. At 100 ppm, the control was preferred to
lufenuron-treated discs, indicating that lufenuron may not elicit attractant
properties at this concentration. Lufenuron expressed a strong correlation
between concentration and slope of the mean % of survivors (R2 =0.899).
As treatment concentrations increased, their slopes increased (or became less
negative). Lufenuron also exhibited a strong negative correlation between
mean area remaining and mean % of survivors (R2 =0.713). A strong linear
relationship between the amount of treated material consumed and the num-
ber of termites that died was observed, and lufenuron was the only BPU that
showed the relationship between the amount of treated material consumed
and mortality so clearly (see Figure 2). Previously, lack of mortality has been
attributed to the deterrence of feeding at higher concentrations for other
chemicals. Interestingly, lufenuron was the only BPU that did not show a
22 Sociobiology Vol. 50, No. 3, 2007
strong correlation (R2 =0.195) between the mean percent of survivors and
the slope. is was due to the rapid mortality observed at higher concentra-
tions (e.g., the slope at 1000 ppm) (Table 2). One concern from these results
might be that lufenuron may have a more direct dose-response relationship,
whereby a greater number of termites may die before they are capable of dis-
seminating the active ingredient throughout the colony (or before deleterious
chitin inhibition occurs); a broader number of concentrations should be
used to determine where the threshold is and subsequent eld evaluations
should be considered.
When evaluating the impact of CSIs on the survival and egg viability of
another rhinotermitid termite, Coptotermes formosanus, Rojas & Morales-
Ramos (2004) observed no statistical dierences in egg viability as all CSIs
prevented larva from hatching, and with rst instars failing to eclose; no
dierences were observed in the mortality of queens and kings exposed to
diubenzuron and hexaumuron treatments and controls. Only lufenuron
treatments showed signicantly increased mortality rates within a month of
exposure to the active ingredient. Furthermore, Rojas and Morales-Ramos
(2004) also observed that the estimated number of eggs oviposited during the
rst 100 d was signicantly lower in the lufenuron treatment group compared
to hexaumuron, diubenzuron, and controls. ey suggest that lufenuron
appeared to be the most potent of the CSIs tested against primary queens
and kings of C. formosanus and that hexaumuron was the least potent,
showing no dierence in adult mortality between treatments and controls
aer 6 mo of exposure.
Based on this preliminary investigation, lufenuron, particularly at low
concentrations, has great promise for termite control if incorporated into
a termite bait matrix. In general, most of the benzoylphenyl ureas exhibit a
lot of variability in their palatability and acceptance by R. avipes, but show
potential for use in remedial termite baiting systems at some concentrations.
Diubenzuron, although acceptable to feeding by these termites, lagged behind
the other three BPUs in the level of mortality exacted to R. avipes under these
experimental constraints. With the demonstrated success of several CSIs for
remedial termite control, results of this study suggest that lufenuron should
be given careful future consideration for potential evaluation as another active
23
Vahabzadeh, R.D. et al.R.Flavipes mortality to CSIs
ingredient which may reliably control unwanted termite populations.
REFERENCES
Ahmad, M., Z. Salihah, N. Sultana & S. Ahmad. 1986. Preliminary studies on the eects
of diubenzuron (Dimlin) on termites (Isoptera). Pakistan Journal of Zoology 18:
403-409.
Austin, J. W., A. L. Szalanski, R. H. Scherahn & M. T. Messenger. 2005. Genetic variation
of Reticulitermes avipes (Isoptera: Rhinotermitidae) in North America Applying the
mitochondrial rRNA 16S Gene. Ann. Entomol. Soc. Am. 98: 980-988.
Austin, J. W., A. L. Szalanski, M. T. Messenger, J. A. McKern & R. E. Gold. 2006. Genetic
variation and phylogenetics of Reticulitermes(Isoptera: Rhinotermitidae) from the
American Great Plains. Sociobiol.48: 427-445.
Becker, B. 1978. Eects of 20-hydroxy-ecdysone, juvenile hormone, dimilin, and captan
on in vitro synthesis of peritrophic membranes in Calliphora erythrocephala. J. Insect
Physiol. 24: 699-705.
Blumberg, D., S. Doron & S. Bitton. 1985. Eect of triumuron on two species of Nitidulid
beetles, Carpophilus hemipterus and Uropohorus humeralis. Pyhtoparasitica 13: 9-19.
Bogwitz, M. R., H. Chung, L. Magoc, S. Rigby, W. Wong, M. O’Keefe, J. A. McKenzie, P.
Batterham & P. J. Daborn. 2005. Cyp12a4 confers lufenuron resistance in a natural
population of Drosophila melanogaster. Proc. Nat. Acad. Sci. 102: 12807–12812.
Broce, A. B. & V.G. Gonzaga. 1987. Eect of substituted benzylphenyls and triumuron on
the reproduction of the face y (Diptera:Muscidae). J. Econ. Entomol. 80: 37-43.
Clarke, L., G.H.R. Temple, & J.F.V. Vincent. 1977. e eects of a chitin inhibitor-dimilin-
on the production of peritrophic membrane in the locust, Locusta migratoria. J. Insect
Physiol. 23: 241-246.
Cornelius, M. L. & W. L. A. Osbrink. 2001. Tunneling behavior, foraging tenacity
and wood consumption rates of Formosan and Eastern subterranean termites
(Isoptera:Rhinotermitidae) in laboratory bioassays. Sociobiology 37: 79-94.
DeMark, J. J. & G. W. Bennett. 1989. Ecacy of chitin synthesis inhibitors on nymphal
German cockroaches (Dictyoptera: Blatellidae).
Doppelreiter, L. &M. Korioth. 1981. Inhibition of development of the subterranean termites
Heterotermes indicola and Reticulitermes avipes caused by diubenzuron (Dimlin). Z.
angew Ent. 91: 131-137.
Eisa, A. A., M. A. El-Fatah, A. El-Nabai & A. A. El-Dash. 1991. Inhibitory eects of some
insect growth regulators on the developmental stages, fecundity and fertility of the
Florida wax scale, Ceroplastes oridensis. Phytoparasitica 19: 49-55.
Elek, J. A. & B. C. Longsta. 1994. Eect of chitin-synsthesis inhibitors on stored-product
beetles. Pestic. Sci. 40: 225-230.
Esenther, G. R. & R. H. Beal. 1974. Attractant-Mirex bait suppresses activity of Reticulitermes
spp. J. of Econ. Entomol. 67: 85-88.
Esenther, G. R. & R. H. Beal. 1978. Insecticidal baits on eld plot perimeters suppress
24 Sociobiology Vol. 50, No. 3, 2007
Reticulitermes. J. of Econ. Entomol. 71: 604-607.
Esenther, G. R. & D. E. Gray. 1968. „Subterranean termite studies in Southern Ontario.
e Canadian Entomologist 100: 827-834.
Forschler, B. T. & J. C. Ryder, Jr. 1996a. Subterranean termite colony response to baiting
with hexaßumuron in Georgia. Down to Earth 15: 30-35.
Forschler, B. T., and J. C. Ryder, Jr. 1996b. Subterranean termite, Reticulitermes spp. (Isoptera:
Rhinotermitidae) colony response to baiting with hexaumuron using a prototype
commercial baiting system. J. Entomol. Sci. 31: 143-151.
Furman, B. D. 2000. Prediction of spring subterranean termite swarms in Texas with relation
to temperature and precipitation. Texas A&M University, College Station, Texas.
esis, 44 pp.
Gold, R. E., H. N. Howell Jr., B. M. Pawson, M. S. Wright & J. C. Lutz. 1996. Evaluation
of termiticides residues and bioavailability from ve soil types and locations in Texas.
Sociobiology 28: 337-363.
Grace, J. K., A . Abdallay & K . R . Farr. 1989. Eastern subterranean termite
(Isoptera:Rhinotermitidae) foraging territories and populations in Toronto. Canadian
Entomologist 121: 551-556.
Grace, J. K. & N. Y. Su. 2001. Evidence supporting the use of termite baiting systems for
long-term structural protection (Isoptera). Sociobiology 37: 301-310.
Graf, J. F. 1999. e role of insect growth regulators in the control of ectoparasites. World
Assaciation for the Advancement of Veterinary Parasitology, 17th International
Conference., Novartis Animal Health. Scientic Communications.
Haagsma, K. & J. Bean. 1998. Evaluation of a hexaumuorn-based bait to control subterranean
termites in Southern California (Isoptera:Rhinotermitidae). Sociobiology 31: 363-
369.
Heintschel, B.P, J. W. Austin & R.E. Gold. 2006. Soldier Labral Morphology and Genetic
Comparison of Reticulitermes (Isoptera:Rhinotermitidae) from Texas. Sociobiol. 48:
63-84.
Heintschel , B. P., C.M. Kenerley & R. E. Gold. 2007. Eects of Trichoderma virens fungus on
the feeding behavior of the subterranean termite Reticulitermes virginicus. Sociobiology.
50: 223-244.
Jones, S. C. 1984. Evaluation of two insect growth regulators for the bait-block method
of subterranean termite (Isoptera:Rhinotermitidae) control. J. Econ. Entomol. 77:
1086-1091.
Jones, S. C. & J. P. LaFage. 1980. Brushing up on the Formosan termite. Pest Control 48:
14-20.
Kistner, D. H. & R. J. Sbragia. 2001. e use of the Sentricon Termite Colony Elimination
System for controlling termites in dicult control sites in Nothern California.
Sociobiology 37: 265-280.
Knapp, F. W. & J. E. Cilek. 1988. Mortality of eggs and larvae obtained from house ies
(Diptera: Muscidae) exposed to triumuron residues. J. Econ. Entomol. 81: 1662-
1664.
25
Vahabzadeh, R.D. et al.R.Flavipes mortality to CSIs
Kurichan, I & R.E. Gold. 1998. Evaluation of the Ability of Reticulitermes avipes Kollar, a
Subterranean Termite (Isoptera:Rhinotermitidae), to Dierentiate Between Termiticide
Treated and Untreated Soils in Laboratory Tests. Sociobiology. , 32: 151-166.
Liu, M-Y, J. & J. E. Casida. 1993. High anity binding of [3H] imidacloprid in the insect
acetylcholine receptor. Pestic. Biochem. Physiol. 46: 40-46.
Meisner, J., K. R. S. Ascher & F. Assi. 1987. Eect of some benzoylphenyl ureas on Earias
insulana eggs of dierent age. Phytoparasitica 15: 91-96.
Meola, R. W., S. R. Dean, S. M. Meola, H. Sittertz-Bhatkar & R. Schenker. 1999. Eect of
lufenuron on chorionic and cuticular structure of unhatched larval Ctenocephalides felis
(Siphonaptera:Pulicidae). J. Med. Entomol. 36: 92-100.
Morales-Ramos, J. A., M.G. Rojas & H. Sittertz-Bhatkar. 2006. Eects of Diubenzuron
on the Peritrophic Matrix and Fat Body of Formosan Subterranean Termite (Isoptera:
Rhinotermitidae) Workers. Sociobiology. 47: 667-676.
[NPMA]National Pest Management Association. 2004. Protect your largest investment: check
home for termites. (http://65.217.229.171/media/art_protect_your_home.asp).
Pawson, B. M & R.E. Gold. 1996. Evaluations of Baits for Termites (Isoptera:Rhinotermitidae)
in Texas. Sociobiology. 28: 485-510.
Pedigo, L. P. 1996. Management by modifying insect development and behavior. Entomology
& Pest Management. C. E. Stewart, C. Hass and M. Carnis. Upper Saddle River, NJ,
Prentice-Hall Inc.: 455-478.
Peppuy, A., A. Robert, J. Delbecque, J. Leca, C. Rouland & C. Bordereau. 1998. Ecacy of
hexaumuron against the fungu-growing termie Pseudacanthotermes spiniger (Sjöstedt)
(Isoptera, Macrotermitinae). Pestic. Sci., 54: 22-26.
Peters, B. C. & C. J. Fitzgerald. 1999. Field evaluation of the eectiveness of three timber
species as bait stakes and the bait toxicant hexaumuron in eradication Coptotermes
acinaciformis (Frogatt)(Isoptera:Rhinotermitidae). Sociobiology 33: 227-238.
Prabhakara, S. K. 2001. Easter subterranean termite management using baits containing
hexaumuron in aected University of Iowa Structures (Isoptera:Rhinotermitidae).
Sociobiology 37: 221-233.
Ring, D. R., A. L. Morgan, W. D. Woodson, A. R. Lax, X. P. Hu, E. D. Freytag & L. Mao.
2001. e rst two years of an area-wide management program for the Formosan
subterranean termite (Isoptera:Rhinotermitidae) in the French Quarter, New Orleans,
Louisiana. Sociobiolog y 37: 293-300.
Rojas, M. G. & J. A. Morales-Ramos. 2004. Disruption of reproductive activity of Coptotermes
formosanus (Isoptera: Rhinotermitidae) primary reproductive by three chitin synthesis
inhibitors. J. Econ. Entomol. 97: 2015-2020.
Sheets, J. J., L. L. Karr & J. E. Dripps. 2000. Kinetics of Uptake, Clearance, Transfer,
and Metabolism of Hexaumuron by Eastern Subterranean Termites (Isoptera:
Rhinotermitidae). J. Econ. Entomol. 93(3): 871-877.
Smith, K. A. & A. A. Grigarick. 1989. Triumuron: residual activity and ovicidal longevity
in the rice water weevil (Coleoptera: Curculionidae). J. Econ.Entmol. 82: 645-648.
26 Sociobiology Vol. 50, No. 3, 2007
Soltani, N. 1984. Eects of ingested diubenzuron on longevity and the peritophic membrane
of adult mealworm (Tenebrio molitar L.). Pestic. Sci. 15:221-225.
Soltani, N. 1987. Diubenzuron-induced alterations during in vitro development of Tenebrio
molitor pupal integument. Arch. Insect Biochem. Physiol. 5: 201-209.
SPSS Inc. 2001. SPSS Base 12.0 for Windows User’s Guide. SPSS Inc., Chicago IL.
Su, N. Y. 1994. Field evaluation of a hexaumuron bait for population suppression of
subterranean termites (Isoptera: Rhinotermitidae). J. of Econ. Entomol. 87: 389-
397.
Su, N. Y., P. M. Ban & R. H. Scheran. 1997. Remedial baiting with hexaumuron in above-
ground stations to control structure-infesting populations of the Formosan subterranean
termite (Isoptera: Rhinotermitidae). J. Econ. Entomol. 90: 809-817.
Su, N. Y., P. M. Ban & R . H. Scheffran. 2001. Control of subterranean termites
(Isoptera:Rhinotermitidae) using commercial prototype above-ground stations and
hexaumuron baits. Sociobiology 37: 111-120.
Su, N. Y. & R. H. Scherahn. 1991. Laboratory evaluation of two slow-acting toxicants
against Formosan and eastern subterranean termites (Isoptera:Rhinotermitidae).» J.
Econ. Entomol. 84: 170-175.
Su, N. Y. & R. H. Scherahn. 1993. Laboratory evaluation of two chitin synthesis inhibitors,
hexaumuron and diubenzuron, as bait toxicants against Formosan and eastern
subterranean termites (Isoptera:Rhinotermitidae). J. Econ. Entomol. 86: 1453-1457.
Su, N. Y. & R. H. Scherahn. 1996(a). Comparative eects of two chitin syhthesis
inhibitors, hexaumuron and lufenuron, in a bait matrix against subterranean termites
(Isoptera:Rhinotermitidae). J. Econ. Entomol. 89: 1156-1160.
Su, N. Y. & R. H. Scherahn. 1996(b). Fate of subterranean termite colonies (Isoptera) aer
bait applications - An update and review. Sociobiology 27: 253-275.
Su, N. Y. & R. H. Scherahn. 2000. Termites as Pests of Buildings, pp. 437-453. In T. Abe
et al. (eds.), Termites: Evolution, Sociality, Symbioses, Ecology. Kluwer Academic
Publishers, the Netherlands.
Su, N.Y. & M. T. Messenger. 2000. Measuring Wood Consumption by Subterranean Termites
(Isoptera: Rhinotermitidae) with Digitized Images. J. Econ. Entomol. 93: 412-414.
Su, N. Y., R. H. Scherahn & P. M. Ban. 1989. Method to monitor initiation of aerial
infestations by alates of the formosan subterranean termite (Isoptera:Rhinotermitidae)
in high-rise buildings. J. Econ. Entomol. 82: 1643-1645.
Su, N. Y., M. Tamashiro & M. I. Haverty. 1987. Characterization of slow-acting insecticides for
the remedial control of the Formosan subterranean termite (Isoptera:Rhinotermitidae).
J. Econ. Entomol. 80: 1-4.
Su N.Y 2002. Novel technologies for subterranean termite control. Sociobiol. 40::95–
101.
27
Vahabzadeh, R.D. et al.R.Flavipes mortality to CSIs
Szalanski, A. L., J. W. Austin & C. B. Owens. 2003. Identication of Reticulitermes spp.
(Isoptera: Rhinotermitidae) from South Central United States by PCR-RFLP. J. Econ.
Entomol. 96: 1514-1519.
Tomlin, C. D. S. (ed). 2000. e Pesticide Manual. Farnham, Surrey GU9 7PH, UK. British
Crop Protection Council.
Tsunoda, K., Y. Hikawa & T. Yoshimura. 2001. Ecacy of hexaumuron as a bait toxicant in
the eld using a transferred nest of Coptotermes formosanus (Isoptera: Rhinotermitidae).
Sociobiology 37: 261-263.
Vahabzadeh, R. D. 2002. Eects of four chitin synthesis inhibitors on feeding and
mortality of the eastern subterranean termite, Reticulitermes avipes Kollar (Isoptera:
Rhinotermitidae). Texas A&M University, College Station, Texas. esis. 77 pp.
Vargo, E. L. 2003. Genetic Structure of Reticulitermes avipes and R. virginicus (Isoptera:
Rhinotermitidae) Colonies in an Urban Habitat and Tracking of Colonies Following
Treatment with Hexaumuron Bait. Environ. Entomol. 32(5): 1271-1282.
Wilps, H. & B. Diop. 1997. e eects of the insect growth regulator triumuron (‘Alsystin’)
on hopper bands of Schistocerca gregaria. Int. J. Pest Manag. 43: 19-25.
... King et al. (2005) reported that noviflumuron acted faster and caused higher mortality than diflubenzuron in R. flavipes. Vahabzadeh et al. (2007) found that bait containing diflubenzuron was acceptable by R. flavipes, but it caused significantly lower mortality than baits with lufenuron, hexaflumuron, or triflumuron. According to Osbrink et al. (2011), diflubenzuron bait exerted no noticeable effect on C. formosanus and R. flavipes, whereas chlorfluazuron and hexaflumuron were more effective. ...
... Kubota et al. (2006) observed that for Coptotermes formosanus (Rhinotermitidae) workers, bistrifluron was slightly more efficacious than hexaflumuron, though bistrifluron in the bait caused some feeding repellency at !5000 ppm. Vahabzadeh et al. (2007) found that lufenuron as a bait component was superior to hexaflumuron against R. flavipes. This finding is in contrast to an earlier study on R. flavipes and C. formosanus (Rhinotermitidae) by Su and Scheffrahn (1996), who 43 Applied Aspects of Insect Growth Disruptors concluded that the overall potential of lufenuron as a bait toxicant is less than that of hexaflumuron. ...
... This finding is in contrast to an earlier study on R. flavipes and C. formosanus (Rhinotermitidae) by Su and Scheffrahn (1996), who 43 Applied Aspects of Insect Growth Disruptors concluded that the overall potential of lufenuron as a bait toxicant is less than that of hexaflumuron. Vahabzadeh et al. (2007) also found that hexaflumuron and triflumuron showed similar acceptability and caused similar mortality in R. flavipes. In this study, diflubenzuron was acceptable by the termites, but its activity was inferior to the other CSIs tested. ...
Chapter
Since the initial suggestion of using insect hormones or their mimics as the third-generation insecticides, great strides have been made in the discovery of three classes of such insect growth-disrupting insecticides. We propose the use of the term " insect growth disruptors" instead of the mis-named term " insect growth regulators" We review the commercial insecticides that mimic the mode of action of the insect growth and development hormones, the sesquiterpenoid juvenile hormones and the steroidal 20-hydroxyecdysone and the third class of insecticides that disrupt growth and development by interfering with chitin synthesis in target insect pests. In this chapter, the emphasis is on the application of these insecticides to control insect pests and development of resistance. Since the non-steroidal ecdysone agonist insecticides have been extensively reviewed in other chapters of this volume and elsewhere, only salient features of these novel insecticides are discussed.
... CSI also prevents normal formation of peritrophic membrane (Zimmermann & Peters, 1987); as a result, the insects become more susceptible to infection by microorganisms such as nuclear polyhedrosis virus (Arakawa et al., 2002). Several chitin synthesis inhibitors such as diflubenzuron, hexaflumuron, noviflumuron, lufenuron, and novaluron have been used or tested with various degree of success in termite baiting systems (Su, 1994; RESEARCH ARTICLE -TERMITES Cabrera and Thoms, 2006;Vahabzadeh et al., 2007;Lewis & Forschler, 2010;Osbrink et al., 2011). ...
... Contrary to the reports that lufenuron treatment elicited feeding deterrence at >1000 ppm for C. formosanus and >50 ppm for R. flavipes (Su & Scheffrahn, 1996), the present multi-chamber tests indicate that lufenuron does not cause noticeable feeding deterrence to C. formosanus at 1500 ppm. Feeding deterrence was not reported by Vahabzadeh et al. (2007) at any concentration (0.1-1000 ppm) tested. In fact, the authors mentioned that lufenuron was highly acceptable to R. flavipes and was the most palatable of the 4 chemicals evaluated: lufenuron, diflubenzuron, hexaflumuron and triflumuron. ...
... lufenuron (1500 ppm) inflicted a significantly higher mortality than the higher concentrations of either diflubenzuron (2500 ppm) or noviflumuron (5000 ppm) in 6 weeks. These results are consistent with the findings by Vahabzadeh et al. (2007) who reported that lufenuron caused significantly higher mortality than diflubenzuron in 6 weeks for Reticulitermes flavipes (Kollar). Rojas and Ramos (2004) found significantly lower queen fecundity in the lufenuron treatments but not in the diflubenzuron or hexaflumuron treatments when compared with the control. ...
Article
Use of chitin synthesis inhibitors has revolutionized the potential impact of termite baiting systems. Several chitin synthesis inhibitors have been used or tested against subterranean termites. We evaluated the effect of lufenuron on bait matrix consumption and mortality of Coptotermes formosanus and compared it with 2 other chitin synthesis inhibitors presently used for termite control: diflubenzuron and noviflumuron. Laboratory no-choice and multi-chamber bioassay designs were employed. At the end of 6 weeks, in both the no-choice and multi-chamber tests, mortality was significantly higher in all the chitin synthesis inhibitor treatments as compared to the controls; however, lufenuron treatment had significantly higher mortality than the other chitin synthesis inhibitors. Multi-chamber tests suggested no sign of feeding deterrence with any of the chitin synthesis inhibitors at the concentrations tested. Consumption of lufenuron cardboard or noviflumuron bait matrix was similar to that of control cardboard in the no-choice tests. We conclude that, based on the overall bait consumption and mortality data, lufenuron was at least as effective as noviflumuron and diflubenzuron.
... Maintaining healthy termites in bioassay is essential when comparing experimental results (Lenz & Williams 1980) and we established a threshold of <19% mortality in the control group before including a replicate in our data analysis. Maintaining termites in small plastic containers for months is a difficult process as indicated by publications, such as Vahabzadeh et al. (2007) (Merzendorfer 2013). Factors that can influence frequency of molting and, therefore, time to CSI mortality would include temperature. ...
... In addition, if termites are unable to move from the CSI feeding site, transfer is negated. The mortality results from our bioassay (Table 1) and the work of Lewis and Power (2006), Vahabzadeh et al. (2007), and Gautam and Henderson (2014) indicates that feeding on lufenuron-treated cardboard bait provides transfer comparable to other CSIs in the confines of a laboratory arena. Yet, we observed lufenuron donors displayed a characteristic stance with antennae held straight forward in a "V" orientation when viewed from above. ...
Article
Full-text available
Eastern subterranean termite, Reticulitermes flavipes (Kollar), workers were exposed for 7 days to one of five chitin synthesis inhibitors (CSIs): diflubenzuron, hexaflumuron, lufenuron, noviflumuron, and novaluron in commercially available bait matrices. Following a 7 day exposure period, termite donors (D) were combined with naïve (not exposed) termite recipients (R) at five D:R ratios (20:0, 15:5, 10:10, 5:15, and 1:19) and mortality determined daily for up to 68 days. Lethal time and percent mortality data suggest efficient transfer at all D:R ratios for all CSIs tested, except diflubenzuron at 1:19. Despite the data indicating transfer of lufenuron in bioassay, this material may not be effective in field use based on behavioral observations that include limited movement by donors. We also report frequency of visible evidence of CSI intoxication, including the previously described “jackknife” pose and an additional physical deformity, we term “curled-body”. The implications these data and observations have for laboratory evaluation and field population management using commercial termite baiting systems is discussed.
... It is likely that only a portion of a colony's workers can actively forage at any given time (Du et al. 2017;Su et al. 2017;Yang et al. 2009). The number of active foragers may vary by species and colony size and may even differ among CSI formulations (Gautam and Henderson 2014;Lewis and Forschler 2017;Osbrink et al. 2011;Su and Scheffrahn 1993;Sukartana et al. 2009;Vahabzadeh et al. 2007). Formulations and label directions of most current commercial CSI termite bait products are designed to result in the highest possible number of termites feeding on the highest possible amount of bait to ensure colony elimination, regardless of the conditions, including the existence of multiple subterranean termite colonies around a treated structure. ...
Article
Full-text available
Termite bait products that contain chitin synthesis inhibitors (CSIs) protect structures from subterranean termites via colony elimination. A hallmark of CSI baits is their dose-independent lethal time, as workers exposed to a CSI do not die until they initiate the molting process. Due to this mode of action and termite behaviors such as trophallaxis and cannibalism, a relatively small quantity of ingested CSI can spread throughout an entire colony before secondary repellency or avoidance behaviors occur, ultimately resulting in total colony elimination. In the field, only a portion of a subterranean termite colony actively forages upon a CSI bait at any given time, suggesting that only a relatively small proportion of workers may need to feed upon a CSI bait for a colony to be eliminated. In the present study, we used varying proportions of workers from whole four-year-old laboratory-reared Coptotermes gestroi (Wasmann) colonies (~ 62,500 termites/colony on average) to determine what proportion of workers need to feed upon a CSI bait in order to achieve colony elimination. A range of 0% (control), 0.5%, 1%, 2.5%, and 5% of the total worker population of colonies was allowed to feed on a formulated 0.5% noviflumuron bait for five days before being returned to their colonies. Colony elimination was observed for all 5%-fed and four out of six 2.5%-fed colonies by 107 days after CSI exposure. Our results confirm that only a small subset of the worker population of a colony must feed upon a CSI bait to achieve subterranean termite colony elimination.
... Inactivity of roughly 70% of the colonies in the treatment site occurred within 4-8 weeks after baiting. The time to elimination is dependent on how soon a colony starts to feed on the CSI baits [58,59], and as these colonies were active in the stations at the time novaluron was introduced, it is presumed that feeding started immediately. Decreased time to colony elimination has also been shown in other baiting systems that induce immediate feeding (i.e. ...
Article
Full-text available
Simple Summary: Subterranean termites cause damage to man-made structures around the world and are continuing to invade new areas. Current practices for controlling termites generally target a single colony as workers tunnel near these structures, and although they are effective in most instances, they never reduce the overall termite pressure in the surrounding area. An area-wide approach to pest management could offer a way of controlling termites at the population level. By eliminating all or most of the colonies within a given area, the threat of infestation decreases. We tracked individual termite colonies over time, before and after the introduction of termite baits, to assess how long these colonies remained active to determine if a termite-free area could be maintained with continued baiting. This baiting approach was successful in significantly reducing the overall termite population within a baited area. Abstract: We investigated the use of termite baiting, a proven system of targeted colony elimination, in an overall area-wide control strategy against subterranean termites. At two field sites, we used microsatellite markers to estimate the total number of Reticulitermes colonies, their spatial partitioning , and breeding structure. Termite pressure was recorded for two years before and after the introduction of Trelona ® (active ingredient novaluron) to a large area of one of the sites. Roughly 70% of the colonies in the treatment site that were present at the time of baiting were not found in the site within two months after the introduction of novaluron. Feeding activity of the remaining colonies subsequently ceased over time and new invading colonies were unable to establish within this site. Our study provides novel field data on the efficacy of novaluron in colony elimination of Re-ticulitermes flavipes, as well as evidence that an area-wide baiting program is feasible to maintain a termite-free area within its native range.
... Neurotoxin, metabolic inhibitors or chitin synthesis inhibitors are used in termite baits (Evans and Iqbal, 2014). Chitin synthesis inhibitors like hexaflumuron, diflubenzuron, triflumuron, lufenuron and noviflumuron inhibit the molting process of termites and cause delayed mortality (Su and Scheffrahn, 1996;Vahabzadeh et al., 2007 andXing et al., 2014). An exclusion hypothesis was the idea behind treatments in which synthetic pyrethroids or organophosphates were used for soil treatments to prevent infestation of the structures by repelling termites (Forschler, 2009) which is accordance with our present investigation. ...
Article
Full-text available
In this experiment a new insecticide molecule, spinetoram 12 SC was taken up to evaluate its antifeedant and repellent activity in laboratory and efficacy in the field with different mode of application against termite control. Laboratory experiments were conducted in Insectary, Agricultural College and Research Institute, Madurai. Field experiments were laid out in Randomized Block Design at farmer's field located in Mandhikanmai village, Kalayarkoil Block, Sivagangai district during 2014-2015 and to study the effect of sett treatment and soil drenching of spinetoram 12 SC with variety CO 86032. At the time of planting, sugarcane setts were treated with various doses of spinetoram 12 SC (90, 120, 150 and 180 g a.i./ha) and covered with soil. After planting in 35 days old sugarcane soil drenching treatment was also effected with the same dose of sett treatment. Imidacloprid 20 SL, Rynaxypyr 20 SC and chlorpyrifos 20 EC were standard checks. The cumulative mean food consumption was minimum 0.71 g, 0.78 g, 1.02 g, 1.23 g, 1.44 g and 1.56 g in various concentrations of spinetoram viz., 360, 300, 240, 180, 120 and 60 ppm, respectively. The highest mean per cent repellent action was noticed in spinetoram 360 ppm and 300 ppm (93.4 and 91.2%, respectively) at 12 HAT. Field experiments were inferred that spinetoram 12 SC 180 and 150 g a.i./ha were significantly effective in minimizing number of termite colony per plot, number of termites per colony and per cent sett damage in both sett treatment and soil drenching methods. How to view point the article : Muthukrishnan, N. and Visnupriya, M. (2019). Antifeedant activity and field evaluation of spinetoram 12 SC against termite, Odontotermes obesus on sugarcane. Internat. J. Plant Protec., 12(2) : 87-93,
... In the present study two insect growth regulators, hexaflumuron and lufenuron have been tested against H. indicola. Hexaflumuron is basically benzophenyl urea which acts as chitin synthesis inhibitor and interrupts the molting process in insects [11] . It has been reported in literature for controlling numbers of insect pests including subterranean termites [12,13] . ...
Article
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The subterranean termite Heterotermes indicola (Wasmann) is one of the most economically important and destructive pest species in Pakistan. It is hard to control with conventional termiticides because of its cryptic foraging behavior and biology. Laboratory studies were conducted at Nuclear Institute for Food and Agriculture (NIFA) Peshawar, Pakistan to test various concentrations ranging from 100 – 10,000 ppm (wt/wt) of hexaflumuron and lufenuron to determine dose response relationship. It was concluded that hexaflumuron caused <50% mortality in termites exposed to 100 – 5000 ppm whereas at 10,000 ppm it caused >70% mortality after 25 days and ELT90 projected was 74 days. In dose-response study of lufenuron all the concentrations equal or greater than 250 ppm caused > 50% mortality but maximum mortality recorded was >70% which was caused by 10,000 ppm and ELT90 recorded was 49.2 days. Both hexaflumuron and lufenuron exhibited characteristics of slow acting toxicants and cause delayed mortalities at all the tested concentrations. Although Lufenuron was found to be relatively more toxic than hexaflumuron but overall mortalities were dose dependent.
... It has also been reported in earlier studies that chitin synthesis inhibitors like lufenuron when used in bait against subterranean termites usually takes weeks to months to show its effect e.g. Rojas and Morales-Ramos [23] reported 8 -9 months, Haverty et al. [24] reported 10 to 16 months, Sukartana et al. [25] reported 6 -8 weeks, King et al. [26] reported 2 weeks and Vahabzadeh et al. [27] reported 6 weeks for lufenuron to show its effects. Ibrahim et al. and Hu et al. [18,19] also explained that delayed affect caused by any termiticide is an added advantage because termite workers will have more time to disseminate the toxicant though out the colony. ...
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Trail following behaviour of subterranean termite, Heterotermes indicola (Wasmann) was studied after exposing them to two insect growth regulators, hexaflumuron and lufenuron. Termite workers were exposed to concentrations ranging from 100 to 10,000 ppm of both IGRs and then data were recorded on percent termite workers that reversed or left trail, time taken to complete the trail and speed with which termites travelled on trail. It was observed that both hexaflumuron and lufenuron did not significantly change the trail following behaviour of the exposed termites and may be used effectively in feeding bait for control of H. indicola.
... products.com/news_releases/news.aspx?idϭ75353). Although this bait has not yet been commercially used, the effectiveness of lufenuron against termite was con-Þrmed both in laboratory and Þeld tests (Lewis and Power 2006, Lovelady et al. 2006, Vahabzadeh et al. 2007, Haverty et al. 2010, Lewis and Forschler 2010, Bowen and Kard 2012, Gautam and Henderson 2014. Most studies tested a concentration of 1,500 ppm lufenuron in termite bait matrix. ...
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This chapter gives an overview of hormones in pest management covering aspects including physiology of insect hormones; concept of insect growth regulators (IGRs); a brief history and evolution of hormone insecticides including juvenile hormone analogues, chitin synthesis inhibitors and ecdysone agonists with details of historical aspects of discovery; innovations on structural modifications leading to development of novel analogues; utility of IGRS in management of crop pests, stored products, in public health and urban pest management; termite management; their impact on natural enemies of crop pests, bees, and other pollinators; and development of resistance in insects to IGRS.
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Five eastern subterranean termite colonies [Reticulitermes flavipes (Kollar)] were characterized using a triple mark recapture procedure around five structures at the University of Iowa, Iowa City, IA. The estimated foraging populations ranged from 720,000 to 2,162,000 individuals occupying an estimated foraging territory of between 91.04m2 to 891.90m2. Sentricon* Termite Colony Elimination System stations (inground, Dow AgroSciences LLC, Indianapolis, IN) were installed within the foraging area of 4 sites and the populations were baited with Recruit* II (Dow AgroSciences LLC, Indianapolis, IN) termite bait containing 0.5% Hexaflumuron. These termite colonies were eliminated after consumption of 112.6g to 571.2g of bait matrix over a period of 3 to 11 months. Continuous monitoring and follow up baiting in the spring was needed to eliminate larger termite populations. At the remaining site, a single colony was eliminated using above ground bait placement alone. This population consumed 348.7g of bait matrix and required 15 months to eliminate all termite activity. The results demonstrate successful colony elimination if monitoring-baiting-monitoring procedures are followed carefully.