|  A sound larviciding program is key in any
successful integrated mosquito management program. A mosquito
spends the first three stages of its life in the water as an
egg, larva, and then pupa prior to hatching out into a full
grown adult. Our larviciding program is designed to control
mosquitoes in the water before they ever have a chance to emerge.
It is crucial when running a mosquito control program to use
tactics that are more economical so the taxpayers can get the
most mosquito control for their money. Larviciding is one of
the most economical ways to control mosquitoes because we are
able to focus on a certain source with our pesticide applications
rather than spraying miles of area for adults. There are many
benefits to controlling mosquitoes in the aquatic stages of
their life. Mosquitoes are both a nuisance and a vector of
many diseases including west Nile virus. When we spray the
mosquitoes as larvae we reduce the chance of there being a
disease or a nuisance situation for that particular site because
the larvae will never mature into adults.
Component of the Larviciding Program at WUVCD
 The
district is divided into 8 larvicide zones.
We have a larviciding technician responsible
for each zone. In our district, there are
1350 potential breeding sites that are checked
weekly.
Each field technician is equipped with a truck, a power
backpack sprayer, a hand powered liquid backpack sprayer,
a map book,
a handheld PDA for data entry, and pesticide. As our
technicians inspect each breeding site, they enter
in the source number,
the larval size and number if present, the habitat,
and the date/time into the PDA. If a treatment is needed,
they then
enter the size of the source, the material and amount
used and the date/time. When the technician returns
to our facility,
the contents on the handheld are then downloaded into
our database.
There are many different types of larvicides on the
market for mosquito control. We use five different
pesticides
in our larviciding program. These five are broken
up into two
classifications,
the biological, which are ingested, and surfactants,
which use suffocation as a mode of action. We use
Bacillus Thurengesis
Isrealanis (Bti), which is a biological pesticide
that is ingested by the mosquito larvae. BTI takes action
within 24 hours and
is specific to mosquito larvae making the environmental
profile
very good. We use BTI in both a liquid and granular
form. Another biological product that we use is Bacillus
Spharecus
(Bs).
Bs is also ingested by the mosquito larvae, however
after the mosquito decomposes the Bs is re-released
into the
water, which
gives us control for up to 30 days. Bs is sprayed
out of a power backpack in a granular form and this product
does
not
adversely affect other aquatic organisms. The surfactants
used are Golden Bear 1111 and Agnique. Golden Bear
is highly refined
oil that is placed on the surface of the water to
suffocate
the larvae and pupae by taking away the surface tension
and not allowing the mosquito to breath. We usually
see result
within 24 hours. Agnique is similar to Golden Bear
by its mode of action, but Agnique is labeled to
be used
on potable
water
if necessary. We use it on ornamental ponds and other
clean water situations. Agnique is effective within
48 hours
after application. |
