ArticlePDF Available

Effect of imidacloprid granules on subterranean termite foraging activity in ground-touching non-structural wood

Authors:

Abstract and Figures

A field trial was conducted to examine the impact of a new granular formulation of imidacloprid on subterranean termite foraging activity and infestation in ground-touching non-structural wood and the longevity of the effect. The trial was carried out in an urban forest with high termite populations and a floor relatively free from brush or deciduous ground cover. The percentages of monitor wood blocks infested and having active termites were reduced to < 8% and < 6%, respectively, while they were >50% and >33%, respectively in population control. The estimated damage rates of monitor wood blocks were also significantly lower in treated than those in control plots. The control effect can last for at least 7 months.
Content may be subject to copyright.
1
Eect of Imidacloprid Granules on Subterranean Termite
Foraging Activity in Ground-touching Non-structural Wood
by
Xing Ping Hu1*, Dunlun Song1,2 & Chip Anderson3
ABSTRACT
A eld trial was conducted to examine the impact of a new granular formula-
tion of imidacloprid on subterranean termite foraging activity and infestation
in ground-touching non-structural wood and the longevity of the eect. e
trial was carried out in an urban forest with high termite populations and a
oor relatively free from brush or deciduous ground cover. e percentages
of monitor wood blocks infested and having active termites were reduced to
< 8% and < 6%, respectively, while they were >50% and >33%, respectively
in population suppression. e estimated damage rates of monitor wood
blocks were also signicantly lower in treated than those in control plots.
e control eect can last for at least 7 months.
Keywords: granular termiticide, soil application, subterranean termite,
population suppression
INTRODUCTION
For more than six decades, soil treatment with liquid termiticides has been
the conventional technique for controlling subterranean termites (Forschler
1999). Even though baiting has become a popular termite control strategy,
two thirds of the treatments are soil applications of liquid termiticides and
more and more pest control companies are using new non-repellent termiti-
cides (Curl 2004).
Soil treatment with liquid termiticides protects structures against ter-
mite infestation by creating a chemical barrier around (and beneath, if it
is pre-construction treatment) the structures. During the post-treatment
1 Department of Entomology and Plant Pathology, Auburn University, Auburn, AL 36849. USA
2 Current address: Department of Entomology, China Agricultural University, Beijing, P.R. China
3Bayer Environmental Science, Professional Pest Management, 2 T. W. Alexander Dr., RTP, NC
27709
* To whom correspondence should be addressed: Email: xhu@aces.edu
2 Sociobiology Vol. 50, No. 3, 2007
period, spot or localized treatments are oen needed due to disturbance of
the chemical barrier during reconstruction, add-on construction, structure
repair, landscaping, utility repairs or soil disturbance resulting in new termite
infestation. ese treatments are oen dicult to schedule and costly, be-
cause of the need for specic equipment and pulling technicians away from
revenue-producing jobs.
In July 2006, a new ready-to-use granular formulation, Premise® Granules,
was approved by the EPA. Premise Granules are intended as a supplemental
treatment to be used with an approved, stand-alone termiticide. Premise
products have imidacloprid as active ingredient, a neonicotinoid that acts as
an insect-specic agonist of nicotinic acetylcholine receptors (Matsuda et al.
2001). As one of the non-repellent termiticides, Premis(Bayer Environmental
Science) has registered as liquid, gel, and foam formulations.
During the second half of 2006, a eld trial was conducted to evaluate
the eect of Premise® Granules' broadcast application on reducing termite
foraging activity and the level of termite infestation of soil contacting non-
structural wood, as well as the longevity of the eect.
MATERIALS AND METHODS
Selection of test site
e experimental trial was conducted at the corner of an urban forest
park not frequented by visitors to satisfy the required minimum 6 months
with minimal disturbance. e main plants were pine trees and the oor was
relatively free from brush or deciduous ground cover. Pre-trial examination of
fallen logs and tree stumps revealed heavy active foraging populations of the
eastern subterranean termite, Reticulitermes avipes (Kollar). Termite species
were identied using keys to soldier and winged adult termites (Scherahn
& Su 1994).
Plot preparations
A series of 12 plots were designed and randomly designated to 6 treated
and 6 untreated (control) plots. e plots were 74 m2 (6 × 24 m) each and
at least 15 m apart from each other.
Application of Premise® Granules
Premise® Granules (0.5% imidacloprid) were provided by Bayer Environ-
3
Hu, X.P. et al — Eect of Imidacloprid Granules On Termite Activity
mental Science (Research Triangle Park, Raleigh, NC, USA). Using a hand-
held rotary spreader (Scotts® handy Green II, Cinnaminson NJ), the product
was broadcasted evenly on the oor at the label rate of 1.8 lb product per
1,000 2 (= 816 g per 92.9 m2). As a result, each plot received 650 g product
containing 3.2 g active ingredient.
Data collection
e trial was initiated May 19th (3 days aer a rainfall of 3.5 cm) and ended
December 2nd 2006. Immediately aer broadcast application, 8 southern yel-
low pine blocks (5 × 10 × 10 cm) were evenly distributed along the center
line and 0.25 m within the boundary of each plot. A brick was placed on top
of each pine block to secure its position. e pine blocks were monitored for
termite activities at bi-weekly intervals for the rst 4 months then monthly
through the next 3 months from May through December of 2006. During
visual observations, digital photos were taken to conrm observations when
it was necessary.
e following 3 variables were recorded: 1) the number of wood blocks
attacked by termites (regardless of the presence of termites); 2) the number
of wood blocks showing the presence of active termites; and 3) estimated
ASTM rating (ASTM 04.10, 2006) of wood blocks (10 = no damage; 9 =
trace feeding; 7 = moderate damage; 4 = heavy damage; 0 = destroyed). Data
were cumulative numbers because aer each monitoring, the wood blocks
were returned to their original locations.
e numbers were calculated as percentages that were arcsine-square root
transformed before data analysis. Signicant dierences between treatment
and control of the 3 variables were analyzed using the two-sample T test at
0.05 probability level (Statistix® 8 soware, Analytical Soware 2003).
Precipitation data were collected using a rain gauge installed at the test
site by taking a reading within 3 hours following a rainfall.
RESULTS
Summarized cumulative percentage of wood blocks showing symptoms
from termite attack (bars) and cumulative percentage of wood blocks show-
ing active termite infestation (lines) are presented in Fig. 1.
4 Sociobiology Vol. 50, No. 3, 2007
Premise® Granules treatment signicantly reduced termite attack compared
to control (F = 104.89, P > 0.05). In treated plots, only <5% of the monitor
blocks were attacked by termites, except for at the end of the trial (≈ 8%),
whereas in control plots, the percentage of attacked blocks increased during
the trial and eventually reached >50% when the trial was terminated.
Correspondingly, the reduction in termite foraging activity was also ex-
hibited by the signicant dierences between actively infested monitor wood
blocks in the treatment and control groups (F = 67.74, P < 0.05). Compared
to the increasing number of actively infested wood blocks from the control
group, the percentage from treated plots remained as low as < 2% during the
rst 5 months and only reached to about 6% at the end of the trial.
e eect of treatment also was evidenced by the cumulative estimated
damage rates, presented in Fig. 2. e damage was hardly visible during the
rst 2 months in both treated and control plots, but estimated damage rates
were signicantly lower in treated than control plots aer that (F = 66.8, P
< 0.05).
Readings from the rain gauge showed very dry conditions from May 19th
Monitoring date (2006)
Fig. 1. Cumulative percentage of monitor wood blocks that were attacked by termites and had presence
of active termites in treated and control plots
5
Hu, X.P. et al — Eect of Imidacloprid Granules On Termite Activity
through August, with only 12.2 cm precipitation (3.5 months). Aer August,
the precipitation averaged 9.2 cm per month.
DISCUSSION AND CONCLUSION
is study indicates that broadcast application of Premise® Granules sig-
nicantly reduced termite foraging activity at the labeled rate, as low as 4.4
g active ingredient per 100 m2. e low termite activity before the middle
of July in both treatment and the control plots could be explained by the
extreme dry condition during that period. However, aer the middle of July
when termite activity in control plots began to increase signicantly, treated
plots retained a very low level of termite activity through the trial, even during
August when there was no rain in that month at all. ese results indicate that
Premise® Granules provided eective suppression of foraging termites last-
ing at least 7 months. Our results are similar to data generated from Georgia
(Bayer Environmental Science, unpublished) and agree with the report from
University of Florida (Oi et al. 2006) that Premise Granules proved eective
in suppressing termite foraging activity, even in extremely dry soil.
Monitoring date (2006)
Fig. 2. Cumulative estimated damage rates of monitor wood blocks in treated and control plots
6 Sociobiology Vol. 50, No. 3, 2007
e Premise® Granules are a ready-to-use product with favorable advantages
such as requiring no mixing or set-up time and stopping existing termite
infestation with minimal equipment. It is labeled to be applied to bare soil,
landscaped areas, turfgrass, mulched areas surrounding structures, and non-
structural wood-to-soil contact areas. Application of Premise Granules should
not be used as a stand-alone treatment but as supplemental spot treatments
for repairing isolated problems and as a perimeter application to suppress
foraging subterranean termite populations.
ACKNOWLEDGEMENTS
We thank Shizhu Li for technical assistance and eorts spent carrying
out the eld trial and collecting data, graduate students Franklin Quarcco
and Lavanya Polana for assisting laying out plots, and Johnny W. Todd for
providing access to a secured eld site. We would like to acknowledge Dr.
Charles Ray and Arthur Appel for critical comments and discussions of this
manuscript.
REFERENCES
Analytical Soware 2003. Statistix® 8 soware. Tallahassee, FL.
ASTM 04.10 2006. ASTM book of Standards, 2006 Edition, Philodelphia, PA.
Curl, G. 2004. Pumped-up termite market. Pest Control. Technol. 32: 28-33.
Forschler, B.T. 1999. Part II: subterranean termite biology in relation to prevention and
removal of structural infestation. In: NPCA research report on subterranean termites.
Dunn Loring, VA. Pp. 31-51.
Matsuda, K., S.D. Buckingham, D. Kleier, J.J. Rauh, M. Grauso & D.B. Sattelle 2001.
Neonicotinoids: insecticides acting on insect nicotinic acetylcholine receptors. Trends
Pharmacol. Sci. 22: 573-580.
Scherahn, R.H. & N.-Y. Su 1994. Keys to soldier and winged adult termites (Isoptera) of
Florida. Fla. Entomol. 77: 460-474.
Oi, F. & J. Paige 2006. Impact of granular imidacloprid on subterranean termites. Presentation
D0381 at the5th Annual Meeting of the Entomological Society of America, December
10-13, Indianapolis, IN.
... 4,5,13,14 Effects of non-repellent compounds on the foraging range and activity of subterranean termites were studied under both laboratory and field conditions. 15,16 The influence of soil compaction, 17 moisture gradients 18 and the presence of sound or decayed wood on tunneling behavior and ability of termites has also been examined. 19 There is still little information, however, on the effects of fipronil and indoxacarb on the tunneling behavior and walking ability of termites. ...
Article
Non-repellent insecticides, including fipronil and indoxacarb, are becoming increasingly important for soil treatments to manage the eastern subterranean termite, Reticulitermes flavipes (Kollar). The effects of these insecticides on termite walking and tunneling behavior could significantly reduce their efficacy against colonies. Groups of R. flavipes were exposed to several concentrations of commercial formulations of fipronil and indoxacarb, and the ability of treated termites to tunnel in soil and walk was assessed. Increasing insecticide concentration resulted in a reduction in the ability of R. flavipes to walk, tunnel and form tunnel branches; the importance of these effects on the use of non-repellent insecticides is discussed. Exposure of R. flavipes to 1, 10 or 50 mg L(-1) of fipronil or 50, 100 or 200 mg L(-1) of indoxacarb significantly reduced termite walking and tunneling and the number of tunnel branches. Distance walked (ca 73 mm) by untreated control termites did not change over time for at least 16 h after treatment; control termites formed ca 150 cm of tunnels with ca 40 branches. Copyright © 2012 Society of Chemical Industry.
Article
Urbanization is progressing worldwide where social insects often attain pest status. We present an overview of the practices applied for the management of social insects in urban settings from 1990 to 2016. We found that most studies focus on the management and/or control of the colony via chemical means, many approaches based on controlling individual workers have been tried with less success than colony-level treatments, and only few used an integrated pest management approach. Less common is undertaking the reduction of populations through the control of the worker caste, by taking advantage of the Allee effects. This is an approach that could be further explored for sustainable control of social insects.
Article
Efficacy data were gathered on imidacloprid (Premise Granules) when; 1) broadcast over an open field site, 2) when used as a "spot treatment" around infested structures for control of subterranean termite populations. Commercial in-ground monitors were installed in the open field site prior to treatments to verify subterranean termite activity. Grids measuring 8.53 m × 7.32 m were marked off, in-ground commercial termite monitors were installed, and grids were treated with Premise Granules. Untreated southern yellow pine surface boards were then placed in grids to determine if Premise" Granules would suppress foraging and feeding on surface boards. Premise Granules suppressed surface feeding of R.flavipes for 9 months post-treatment, although termites were active throughout the study in in-ground commercial termite monitors. For the "spot treatment portion of this study, ten structures with active subterranean termites were utilized (5 treatments and 5 untreated controls). No termite activity was detected on any of the treated structures for 8 weeks post-treatment. However, by 48 weeks 60% of the structures were re-infested. These structures were inspected through 12 months post-treatment.
Article
Illustrated identification keys are presented for soldiers and winged adults of the following 17 termite species known from Florida: Calcaritermes nearcticus Snyder, Neotermes castaneus (Burmeister), N. jouteli (Banks), N. luykxi Nickle and Collins, Kalotermes approximatus Snyder, Incisitermes milleri (Emerson), I. minor (Hagen), I. schwarzi (Banks), I. snyderi (Light), Cryptotermes brevis (Walker), and C. cavifrons Banks, Family Kalotermitidae; Coptotermes formosanus Shiraki, Reticulitermes flavipes (Kollar), R. hageni Banks, R. virginicus (Banks), and Prorhinotermes simplex (Hagen), Family Rhinotermitidae; and Amitermes floridensis Scheffrahn, Mangold, & Su, Family Termitidae. /// Se presentan claves ilustradas de identificacion para los soldados y los adultos con alas de las 17 especies de termes conocidas de la Florida, U.S.A.: Calcaritermes nearcticus (Snyder), Neotermes castaneus (Burmeister), N. jouteli (Banks), N. luykxi Nickle y Collins, Kalotermes approximatus Snyder, Incisitermes milleri (Emerson), I. minor (Hagen), I. schwarzi (Banks), I. snyderi (Light), Cryptotermes brevis (Walker), y C. cavifrons Banks, Familia Kalotermitidae; Coptotermes formosanus Shiraki, Reticulitermes flavipes (Kollar), R. hageni Banks, R. virginicus (Banks), y Prorhinotermes simplex (Hagen), Familia Rhinotermitidae; y Amitermes floridensis Scheffrahn, Mangold, y Su, Familia Termitidae.
Article
Imidacloprid is increasingly used worldwide as an insecticide. It is an agonist at nicotinic acetylcholine receptors (nAChRs) and shows selective toxicity for insects over vertebrates. Recent studies using binding assays, molecular biology and electrophysiology suggest that both α- and non-α-subunits of nAChRs contribute to interactions of these receptors with imidacloprid. Electrostatic interactions of the nitroimine group and bridgehead nitrogen in imidacloprid with particular nAChR amino acid residues are likely to have key roles in determining the selective toxicity of imidacloprid. Chemical calculation of atomic charges of the insecticide molecule and a site-directed mutagenesis study support this hypothesis.
Impact of granular imidacloprid on subterranean termites
  • F J Oi
  • Paige
Oi, F. & J. Paige 2006. Impact of granular imidacloprid on subterranean termites. Presentation D0381 at the5th Annual Meeting of the Entomological Society of America, December 10-13, Indianapolis, IN.
Part II: subterranean termite biology in relation to prevention and removal of structural infestation
  • B T Forschler
Forschler, B.T. 1999. Part II: subterranean termite biology in relation to prevention and removal of structural infestation. In: NPCA research report on subterranean termites. Dunn Loring, VA. Pp. 31-51.
Statistix® 8 software
Analytical Software 2003. Statistix® 8 software. Tallahassee, FL.
Pumped-up termite market
Analytical Software 2003. Statistix® 8 software. Tallahassee, FL. ASTM 04.10 2006. ASTM book of Standards, 2006 Edition, Philodelphia, PA. Curl, G. 2004. Pumped-up termite market. Pest Control. Technol. 32: 28-33.