Environmental & Extension Services - Pest Management
Aquatic
Weed Control 
When
exotic aquatic weeds fill in canals, rivers, ponds, and lakes,
residents typically demand aquatic plant management.
That is where Aquatic Weed Control comes into play.
Because our population has grown precipitously, aquatic weeds
have become more of a noticed problem throughout our county, even in
the previously remote sections of our area.
Residents are, likewise, more likely to notice and question
our Aquatic Weed Sprayers who are managing aquatic weeds.
Indeed, public interest in water resource management has
increased, our knowledge of environmental interactions has
increased, and pesticide technology has become highly refined and
carefully regulated.
The
Federal Insecticide, Fungicide, and Rodenticide Act of 1979 (FIFRA),
as administered by the United States Environmental Protection Agency
(EPA), requires all persons who apply pesticides classified as
restricted use be certified according to the provisions of the act
or that they work under the supervision of a certified applicator.
Commercial and public applicators must demonstrate a
practical knowledge of the principles and practices of pest control
and safe use of pesticides, accomplished through a standard
examination. In
addition, applicators using or supervising the use of any restricted
use pesticides purposefully applied to standing or running water
(excluding applicators performing public health related activities
such as mosquito control) are required to pass an additional
examination to demonstrate competency as described in the code of
federal regulation as follows:
“Aquatic
applicators shall demonstrate practical knowledge of the secondary
effects which can be caused by improper application rates, incorrect
formulations, and faulty application of restricted pesticides used
in this category. They
shall demonstrate practical knowledge of various water use
situations and potential of downstream effects.
Further, they must have practical knowledge concerning
potential pesticide effects on plants, fish, birds, beneficial
insects, and other organisms which may be present in aquatic
environments. Applicants
in this category must demonstrate practical knowledge of the
principles of limited area application.”
Before
any aquatic weed treatment takes place, our Aquatic Weed
Inspector/Sprayers assess many environmental factors.
The type of plant in the body of water to be treated is
determined so the proper herbicide and concentration may be used. (Common
Aquatic Weeds) The
potential for rain in close time proximity to spraying is assessed
because some of the herbicides we utilize may be washed away before
they are able to take effect on the plant.
Wind is also taken into consideration to prevent any drift to
desirable plants in the area. At
less than optimal temperatures, plant growth slows down.
Less than optimal temperatures may decrease herbicide
absorption by the plant and, therefore, its efficacy.
Water chemistry is tested before certain types treatments.
We test for pH, conductivity, and the amount of dissolved
oxygen in the water. These
major factors and other minor ones affect how the herbicide reacts
with the plants. Knowing the dissolved oxygen level before treatment helps to
prevent fish kills which can occur when the target vegetation dies
off quickly, using all available dissolved oxygen to decompose. The Aquatic Inspector/Sprayers are required to wear
protective clothing to prevent exposure to the herbicides through
their skin, clothing, and nose or mouth.
They must follow the guidelines expressed on the herbicide
label to ensure everyone’s safety.
When
a waterway is to be treated, we utilize one of three types of
vehicles: airboat, john boat, or marsh master.
The airboat is able to quickly move around in the waterways. It is also able to traverse through densely vegetated waters. The john boat is utilized in areas of thinner vegetation.
The marsh master, which looks similar to a tank, is used in
shallow waters that have difficult banks to climb.
It is also able to float. Occasionally,
we do not use any vehicle, but spray or pull weeds by hand.
This is usually in mitigated (rebuilt) wetlands or in very
shallow waters.
Pesticide applications are not the only control means our Department utilizes. The USDA has discovered and released many biological control agents for some of our exotic aquatic weeds in Florida.
The USDA and the University of Florida are always
investigating new biological agents to be used as control methods
for our many nuisance exotic weeds.
Our Department also relies on triploid grass carp in some
areas. These grass carp
are sterile and unable to reproduce.
They eat the submerged aquatic weeds that are difficult to
otherwise control. We
stock these fish in specially gated channels to insure they stay
where they are needed.
Frequently Asked Questions about Aquatic Weeds
For more information
Charlotte County Environmental & Extension Services
25550 Harbor View Road, Unit 2, Port Charlotte, FL 33980
941.764.4360
