Sonar - Fluridone Treatments
Sonar is a very versatile chemical that can be used to control nearly
all types of rooted vegetation or can be manipulated to control only one
or two types of vegetation (depending on vegetation tolerance).
Fluridone is the active ingredient in Sonar and works by inhibiting
plants from producing Carotene. With out this substance ultra violet
rays from the sun rapidly degrade the plants chlorophyll and ultimately
lead to the death of susceptible plants. Sonar is a very valuable lake
management tool because of it’s longevity of results and its potential
selectiveness. Properly applied a single Sonar application can provide
results for up to one full growing season. The first step in doing a
Sonar treatment is proper identification of target plant species. This
is critical as all plants have different tolerance levels and therefore
require different treatment rates. For example, if you were treating
Water Milfoil you could use a treatment rate as low as 10 PPB (Parts Per
Billion) where as Salvinia requires 90 PPB. After properly identifying
your vegetation and determining your required treatment rate you have to
consider what Sonar formulation is best for your specific situation.
When determining this you should look at water flow, potential runoff,
time of application, stage of plant growth, and all other factors that
could affect your investment. The different types of formulations have
distinctive characteristics that may make one or a combination of these
perfect for your lake or pond. The types of Sonar currently available
are as follows: Sonar AS – Aqueous Suspension Sonar Q – Quick Release
Sonar SRP – Slow Release Pellets Sonar PR – Precision Release

Pictured left
is an illustration of a few of the different types of Sonar, the Blue
line represents Sonar AS, as the Red line represents Sonar Q. Both of
these are good products and can be affective at controlling vegetation,
but as you can see by the Black line the proper combination of these
products will help maintain the concentration for longer periods
ensuring full results.
The end result of a Sonar treatment is usually evident by 45-90 days but
results can last for up to ten months. The first signs that the
chemicals are taking effect can be seen in seven to ten days from
application. The first signs are often white (chlorotic) or pink to
purple coloration in new growth, this happens because the new growth has
developed with out chlorophyll. The existing vegetation, that already
contains chlorophyll, is now incapable of replenishing this substance
and gradually will follow suit, appear to be bleached and eventually
die. This process takes time and patience but this slower action will
work in your favor. Should the entirety of your vegetation had died
overnight there could be major fish losses due to low dissolved oxygen
levels. One advantage of a slow kill is that the scenario above will be
avoided in most cases; this also allows time for the chemical to
completely penetrate the entire plant and provide a more complete die
off
Pictured Right: Bushy Pondweed 20 days after Sonar application. The
first signs of Sonar are pink to white coloration at the tips or
growing points.

As the target plants begin to die and decay the nutrients that were
previously locked inside of them are now available for consumption
by nontarget species. Algaes are in no way susceptible to Sonar and
are the most common type of growth that occurs during the
decomposition process. Filamentous Algae can form thick mats on top
of decaying plants and make the situation appear worse than it
really is. If you see this happening do not be alarmed as it is a
natural part of the process and will be short lived. As the rooted
vegetation continues to dye and sinks lower into the water the algae
will most likely not be able to support itself in water over 2-3’
deep and will then be confined to the shallow areas of the lake.
There are some restrictions that go along with a Sonar Treatment.
There is a 30-45 day irrigation restriction. We reccommend not
watering your plants or grass with lake water. Still if you must do
so a charcoal-based filter will remove Fluridone residues from the
water. There are no restrictions on swimming, fishing or fish
consumption for Sonar treated waters. Consult the label and MSDS
sheet for a complete list of restrictions and general safety issues.
When all variables have been evaluated and Sonar is applied properly
the results are simply amazing. This is one of the most cost and
time effective treatments that can be performed and provides results
that just can not be duplicated with any other type of treatment.
Should you be considering treating your pond with Sonar consult with
a specialist to ensure timely and proper application. If your pond
has already been treated with Sonar this season, sit back, relax and
enjoy your lake.
Wonder how much it would cost to
treat your lake or pond with Sonar? User our FREE Sonar Calculator