SONAR (FLURIDONE) TREATMENT FOR LOST LAKE, SECRET LAKE, AND MIDDLE LAKE TRIPLET
APPLICATION DATE SCHEDULED FOR MONDAY FEBRUARY 23rd
WHAT IS THIS TREATMENT FOR?
This treatment is for control of the non-native, invasive, aquatic plant hydrilla (Hydrilla verticillata). For
decades hydrilla has been a nuisance aquatic plant found in many water bodies throughout Central
Florida. Due to its lack of locally occurring predators, and its uniquely specialized adaptations, the plant
is capable of rapidly out-competing our native plant populations. Hydrilla’s dense growth pattern can
become a nuisance to most recreational boating activities, and its overgrowth can pose a threat to local
organisms such as fish and macroinvertebrates. However, through the use of proper chemical and
biological controls, hydrilla can be safely and effectively controlled and managed.
DO I NEED TO DO ANYTHING?
If you currently irrigate your yard with water from an affected lake, you will
need to restrict irrigation for two weeks from the treatment date. (These irrigation
restrictions do not apply if your irrigation source is from Casselberry’s reclaimed or potable water lines.)
WHAT CHEMICALS ARE BEING USED AND HOW ARE THEY APPLIED?
The aquatic herbicide Sonar (fluridone) will be applied at a very low concentration, between 12 and 15
parts per billion, through use of an airboat and trailing hoses. One or two “bump” treatments will likely
be necessary to maintain a concentration that is lethal to the target plant. This product will then persist
in the water column at low levels for a few months.
HOW DOES THIS PRODUCT WORK?
Sonar is a systemic herbicide that is slowly absorbed by the target plant over a prescribed period of
time. It inhibits the plant’s ability to photosynthesize and produce its own food, essentially slowly
starving it of nutrients and causing it to die.
WHY IS THIS HERBICIDE NEEDED?
The City of Casselberry has an integrated hydrilla control program that uses a variety of aquatic plant
management tools. Hydrilla densities in these water bodies have reached the point where a full lake
treatment is necessary to sufficiently reduce the plant’s biomass. This product was selected both
because it is the most cost effective treatment for full lake applications, and to provide a rotation in
mode of action in an effort to stave off herbicide resistance.
WHY CAN’T YOU JUST STOCK MORE CARP INSTEAD OF USING HERBICIDE?
Although grass carp are effective at reducing the frequency and scale of herbicide treatments, they
cannot totally replace herbicides. In order to provide complete hydrilla control, grass carp would have
to be stocked in numbers so high that native plant populations would be severely impacted. Preserving
and encouraging the abundance and diversity of our native aquatic plant populations is critical to
Casselberry’s lakes to help maintain water quality and biodiversity. Native aquatic plants provide
habitat, soil stabilization, and produce oxygen; resources that other organisms in the lake depend upon.
These lakes are already stocked with carp at maintenance levels which will help us manage future
hydrilla re-growth.
WHAT EFFECT WILL THIS TREATMENT HAVE?
In the weeks following the initial application, hydrilla shoot tips will begin to turn pink or white. This
bleaching effect will slowly work its way through the plant, and eventually cause it to collapse to the
bottom of the lake or ball up and slowly biodegrade. Floating mats of hydrilla may be seen in the
months following the application. A temporary reduction in water quality characterized by algal blooms
is also common, as nutrients are released from the decomposing vegetation.
WILL I SEE ANY ADDITIONAL SIDE EFFECTS?
Some native aquatic plants, such as water lilies, will be affected by the treatment. As with hydrilla,
bleaching will occur, however the native plants will quickly re-grow after treatment.
WILL THIS PROJECT NEGATIVELY AFFECT WILDLIFE, FISHING, OR SWIMMING?
There are no fishing, swimming, or drinking restrictions for Sonar (fluridone). Fish, birds,
macroinvertebrates, and all other organisms will not be harmed through exposure to this product.
Labeled aquatic herbicides undergo years of extensive testing before they are evaluated and approved
by the U.S. Environmental Protection Agency and the Florida Department of Agriculture and Consumer
Services.
DOES THIS TREATMENT REQUIRE APPROVAL FROM ANY STATE AGENCIES?
The City maintains an Aquatic Plant Control Permit through the Florida Fish and Wildlife Conservation
Commission (FFWCC) for Lost Lake and Middle Lake Triplet, and has been authorized to conduct this
application. Secret Lake is exempt; as the FFWCC does not permit water bodies less than 10 acres.
HOW MUCH DOES THE TREATMENT COST AND HOW IS IT BEING FUNDED?
These treatments are funded through the City’s stormwater utility fee and herbicide is projected to cost
a maximum total of $13,054.86.
WHERE CAN I FIND MORE INFORMATION ABOU THIS PRODUCT?
http://www.sepro.com/default.php?page=sonaras
HOW CAN I HELP PROTECT THESE LAKES AND PREVENT THE SPREAD OF HYDRILLA?
There are a number of actions you can take to help our water bodies and/or prevent the spread of
hydrilla, even if you do not live on a lake. Excess nutrients are the primary source of pollution in our
waterways, leading to algae blooms and also providing a food source for invasive exotic plants. Did you
know it can take only one fragment of an exotic aquatic plant to result in a complete infestation?!
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Always check your boat, trailer, and bilge for aquatic plant “hitchhikers” when entering or
exiting a lake, and dispose of them in a trash collection area, such as a dumpster, when found.
Don’t blow yard debris or grass clippings into the street! This organic material will eventually
be carried to our waterways via stormwater, decompose, and release excess nutrients. Please
mulch or gather and bag these materials to be disposed of by our waste collection services.
For additional information and advice, including many more tips on protecting our lakes,
please visit our website: www.Casselberry.org/lakes
IF I HAVE A CONCERN DURING OF AFTER THE TREATMENT, WHOM SHOULD I
CONTACT?
Questions regarding the treatment and anything related to the City’s lakes
management program can be directed to the Natural Resources Officer, Marissa
Williams, at (407)262-7725 ext. 1229 or [email protected]