Agriculture Reference
In-Depth Information
subterranean termites. Some degree of
transfer of nonrepellent active ingredients
has been demonstrated in the laboratory and
there have been anecdotal reports of colony-
wide effects; however, there had not been
rigorous tests performed in the fi eld to track
colonies after treatment. Both the studies
were conducted on selected houses in the
Raleigh, NC area with subterranean termite
infestations. A grid of in-ground monitoring
stations was installed around the houses,
and samples were collected from the
stations, as well as from mud tubes and
wood debris in the yards on a monthly basis
for 6-9 months. All samples collected were
genotyped for colony identifi cation. After
this initial pre-treatment period, colonies
were treated with either imidacloprid
(Premise®) or fi pronil (Termidor®) by a
licensed pest management professional.
Samples were collected monthly for 3
months and then quarterly for 2 years in the
case of the imidacloprid treatment and 3
years in the case of the fi pronil treatment.
For the imidacloprid treatment, 11
houses were treated (Parman and Vargo,
2010). All but one house was infested by a
single colony, whereas a single house was
attacked by two colonies simultaneously.
Nine of the 12 colonies disappeared from
the study within 90 days of the treatment
and were not detected again. These were
clearly suppressed and most likely
eliminated. In contrast, >70% of the
colonies present in other parts of the yard
that were not near the treatment zone
continued to be redetected, usually many
times. These results are consistent with
signifi cant colony-level effects of imida-
cloprid treatment in the fi eld, resulting in
strong suppression and probably colony
elimination in most cases.
Similar but even more pronounced
effects were obtained with fi pronil (Vargo
and Parman, 2012). This study used eight
houses and monitored the colonies for 3
years. Three of the houses were infested by
two colonies each, whereas the remaining
houses were infested by a single colony. In
this case, all 11 colonies disappeared by the
90-day post-treatment date and none of
them were detected again. Figure 11.2
shows the colonies around a representative
house used in this study. These results
using genetic fi ngerprinting helped prove
strong colony-level effects of fi pronil
treatment, resulting in the suppression or
elimination of all infesting colonies.
Genetic fi ngerprinting of colonies has the
potential to determine the effi cacy of
treatments for ant colonies, although there
is only a single report using this method to
track ant colonies after treatment. Colby
et
al
. (2008) used microsatellite genotyping of
colonies before and after disking of fi re ant
mounds in pastures to determine the effect
of this form of cultural control on fi re ant
colonies. These authors found that most
colonies survived such treatment, demon-
strating that disking is not an effective
method for managing fi re ant colonies in
pastures. Genetic fi ngerprinting of colonies
holds great promise for investigating the
ability of treatments around urban structures
to eliminate colonies of pest ants and we
can expect more studies employing these
techniques in the future.
Detection of Invasive Populations
Invasive species are introduced through
human transport where they become estab-
lished in non-native areas, often causing
signifi cant economic and/or ecological dam-
age. The spread of invasive species is a
signifi cant and increasing problem world-
wide. It comes as no surprise that most
major urban pests are invasive species.
Such species are pests by virtue of their
association with humans and are therefore
easily moved along with human belongings.
Identifying the sources of introduced popu-
lations is an important step in determining
the route of transport. Such information is
critical for developing potential regulatory
measures to prevent future introductions.
Genetic tools have taken a primary role in
helping to identify source populations of
many species, including some important
urban insect pests.
One of the most successful cases of
identifying source populations of an in-
vasive urban pest is the fi re ant,
Solenopsis
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