Agriculture Reference
In-Depth Information
achieve satisfactory control; in such cases it
is best to bait outside to discourage the ants
from continually trailing into the structure.
Insecticide sprays are highly effective and
provide satisfactory control when used
properly. Spray treatments typically last
longer than bait treatments. Depending on
the active ingredient and the environmental
conditions, a typical outdoor spray appli-
cation lasts 4-12 weeks. In contrast, a bait
application may only last a few days before
the bait is completely consumed, degraded
by environmental conditions (e.g. washed
away or dried out), or consumed by non-
targets such as rodents, birds and
occasionally pets. Another difference is the
effective range. Sprays are generally non-
selective and therefore effective on a wide
range of ant species and other peridomestic
pests such as cockroaches, pill bugs,
spiders, earwigs, beetles and crickets.
Despite these advantages, spray insecticides
also have certain drawbacks. Relative to
baits, they use much more active ingredient
and may cause environmental contamin-
ation when used improperly. Both PMPs
and property owners should recognize that
most ant species are benefi cial in the
landscape and rarely become indoor pests.
The entire landscape should not be
routinely treated with spray insecticides,
unless it is infested with fi re ants or other
species that continually enter the home.
Indiscriminate spraying, especially on a
calendar-based basis, is not part of an IPM
programme for ants. In fact, the need to
regularly spray insecticides is a good
indication that the management programme
is not working effi ciently and should be
evaluated for alternative solutions, such as
habitat modifi cation, exclusion or improved
sanitation.
Sprays
Insecticide sprays for ants are most effective
when used outside, around the exterior of
the structure. Most exterior sprays are
applied as barrier treatments and will
continue to kill ants for a period of time,
typically 4-10 weeks. The length of time
depends largely on the active ingredient,
formulation, weather conditions and the
substrate the insecticide is applied to
(porous versus non-porous). The optimal
sprays for ants are those that are slow acting
(i.e. kill exposed ants in a matter of 12-24 h)
and non repellent. Exterior sprays are
typically applied to the structure only and
away from where the majority of ants are
actually nesting. As a result, spray treat-
ments only target the foraging workers that
cross the treatment zone and have no direct
effect on workers that never encounter the
treatment zone or non-mobile stages such as
queens and brood. Such individuals must
obtain the insecticide from the exposed
workers through horizontal transfer
(Soeprono and Rust, 2004). The active
ingredient may be transferred indirectly
most often when exposed individuals con-
taminate water, food or surfaces later used
by unexposed ants. The active ingredient
may also be transferred directly by social
activities taking place in the colony such as
contact, grooming and trophallaxis. To
maximize the effi cacy of spray insecticides
it is best to use them as remedial products to
kill whole colonies directly, especially
those discovered during the inspection. In
urban situations, pest ants often nest in
predictable locations such as under paving
stones, fl ower pots or landscape timbers
that should be inspected and treated directly
if they harbour colonies. The colonies
should be treated quickly, before the ants
disperse, to assure maximum control.
Spray formulations show a number of
attributes that make them highly attractive
and suitable for effective pest management.
Indoor Versus Outdoor Treatments
When treating for ants, pest management
professionals generally have two options:
baits and sprays. Baits and sprays may be
used in a variety of combinations, but a
typical treatment involves spraying outside
and baiting inside. This is especially true
when treating for opportunistic ants that
prefer to nest outdoors but may occasionally
enter buildings in the search for resources.
Search WWH ::
Custom Search