Duckweed
Control
Duckweed
is an agressive pond weed that covers a pond quickly with a green
scum.
Duckweed
(Lemnaoideae) is something I am actually very fond of...of course
when a large pond is infested with this plant it is no fun but in
smaller water gardens and backyard ponds duckweed can actually be
a helpfull addition to the ecosystem! Myself, I've actually gone to
the garden store and bought a container full of duckweed to add to
my backyard pond...it cost me $5 and my wife asked me if I was losing
my marbles because duckweed can be found in almost any farm dugout
or stagnant swamp in the area! I am asked at least twice a week about
methods for controlling duckweed and other aquatic plants and algae
of course.
In a large pond duckweed can be an invasive plant that can cover the
surface quickly and it often is a real nuisance for the pond owner
who suddenly can't see anything in the pond!
Before we kill the duckweed with an aquatic herbacide, yes there are
some good algaecides that can eliminate duckweed from a pond, lets
make sure we actually do want to do it because this floating plant
is actually a real wonder of the pond! Duckweed can absorb a whole
bunch of nutrients from the water and will provide a great umbrella
of shade for fish...so it will keep waters cooler and also suck out
phosphates from the pond. These phosphates and other nutrients are
the junk in the pond that cause the big blooms of floating green algae
and algae that grows on the bottom of the pond.
Why You May Love Duckweed:
Duckweed is a small delicate plant that drifts on the pond surface,
filling in spaces between the lily pads, creating a lovely green blanket
across the pond. This provides a lush habitat for frogs and fish and
insects of the pond. The layer of floating aquatic plants provides
shade to the pond keeping it cooler during stifling hot days of overhead
sun. Waterfowl will feed voraciously on the duckweed thus nest nearby
and live in the pond. Duckweed grows rapidly and absorbs mineral elements
like nitrogen and phosphates from the water column so it can be an
important part in the aquatic rehabilitation of any pond or lake as
these nutrients can cause problems like algae and cyanobacteria. It
is especially good at removing ammonia from ponds. Beyond providing
shade for fry bluegill and a place to live for bullfrogs the duckweed
helps reduce evaporation which can be a problem in a clear pond without
any cover to slow the rate of pond evaporation. Sometimes just the
rich green color of the plant alone is enough to make us feel like
our pond is a healthy and natural aquatic system! A bit like a stained
glass window on the pond, duckweed is a wonderful and beautiful plant,
that with a bit of understanding and acceptance is actually a very
beautiful thing!
Why You May Hate Duckweed:
Duckweed is an invasive and agressive aquatic weed that can rapidly
multiply and if conditions are right will completely cover a pond
with a thick green cover of tiny green plants that are only a few
milimeters in size. The thick matting of pond weed can literally choke
out a pond and if conditions, temperatures and nutrient levels are
right can completely hide the water and create a cover that hides
the pond and makes it almost unpleasant. Frogs and ducks and turtles
will live in what looks like a swamp! Maybe it provides food for swans
and geese and a mallard duck or two but it can choke out oxygen levels.
There are Only Two Ways of Getting
Rid of Duckweed
Well, actually you could just ignore the duckweed and live with the
problem! So that means there are three options for this aquatic plant.
Adding natural bacteria to control muck and nutrients will assist
in slowly reducing the amount of food available for this aquatic floating
bugger. The beneficial bacteria, over time, will have an impact on
the amount of duckweed in your pond...but it can be a long process
and manual removal will greatly help this process. So basicially,
beyond ignoring it you have two ways to deal with duckweed:
1 - The Natural Way
Natural
bacteria for ponds
If the pond is small enough just the best way to remove the small
little flowering plant known as duckweed is to use a fine meshed net
and just manually remove it day by day, hour after hour, until there
is none left. Of course it is really tough to completey eradicate
the problem but you can keep it under control just like keeping the
dandelions out of the vegetable garden!
You need a net with a long handle or a good quality aquatic rake to
harvest this pond weed if you want to deal with this problem naturally
or of course you can invite a family of ducks or geese or swans into
your pond and they will love the free food supply offered by these
floating flowering plants but you will still need the manual removal...if
you don't want to accept the duckweed or don't want to perform the
manual work or invite the Duckworth family into the pond then you
need to go to the next option...
2 - The Chemical Way
Aquatic
herbicides and pond weed killers
 
Aquatic algaecides and herbicides are very effective at controlling
duckwweds and other unwanted invasive pond species. You should understand
that such algae problems, well...it's not reaslly an algae but an
aquatic weed plant, if they are treated with herbiceds can lead to
a dependance or resistance and scientists generally agree that chemical
selection pressure that is applied applied to aquatic weed populations
for a long enough period of time eventually leads to resistance. This
means that while the chemical pond weed killer may work quickly and
effectively for the first few years, unless you are adding a positive
treatment with aeration and natural beneficial bacteria you will just
be "chasing the dragon" so to speak!
WhiteCap®
selective herbicide kills duckweed and more
White Cap Selective Herbicide Control aquatic weeds and grasses in fresh
water ponds, lakes, and drainage/irrigation canals with WhiteCap™
SC selective herbicide, a proven reformulation of the popular active
ingredient fluridone. WhiteCap effectively controls a wide range of
floating, submersed and emersed aquatic vegetation, including Duckweed,
Hydrilla, Bladderwort, Watermilfoil, Naiad, Elodea, Water-lily, Pondweed,
and Coontail See
The List of Aquatic Weeds that White Cap SC will control before you
buy. Email us if you're not sure.
|
WhiteCap® Herbicide
Price Includes USA Shipping
|
8 oz
8 ounce jug WhiteCap® - $225 |
32 oz
32 ounce jug WhiteCap® - $635 |
|
|
|
|
Susceptible
aquatic weeds absorb WhiteCap SC through the shoots and roots. For
effective control, contact of WhiteCap with the target plant must
be maintained for at least 45 days. Effective control is reduced
if conditions exist that dilute the concentration of WhiteCap in
the water to below labeled rates.
Apply WhiteCap as a surface spray or subsurface injection at rates
between 10 and 90 ppb for single applications, or if multiple applications
are made, do not exceed 150 ppb per growing season.
Water treated with WhiteCap SC at rates greater than 5 ppb must
not be used for irrigation of certain crops and newly seeded turf.
If the concentration of WhiteCap is less than 10 ppb, established
tree crops, established row crops or turf can be irrigated with
WhiteCap treated water.
Do not apply WhiteCap at rates greater than 20 ppb within ¼ mile
of any functioning potable water intake.
WhiteCap effectively controls a wide range of floating, submersed
and emersed aquatic vegetation, including Hydrilla, Bladderwort,
Watermilfoil, Naiad, Elodea, Water-lily, Pondweed, Coontail and
Duckweed. Selective control.
At low use rates, it is safe for most native beneficial aquatic
plants; WhiteCap SC selectively removes the nuisance plants, while
having little impact to desirable species. Low
use rates provide for cost-effective aquatic plant control. Download
the WhiteCap instructions in PDF
Complete control.
Readily moves and disperses throughout the water column, providing
complete and thorough control of target nuisance aquatic weeds Slow
control. Works slowly to remove excessive aquatic weeds with minimal
impact to aquatic ecosystems No human or livestock use restrictions.
Water treated is potable water safe and may be used immediately
for human recreation and for watering livestock.
|
Average
Water Depth of Treatment in Feet
|
Fluid
ounces per acre
to achieve desired herbicide concentration
|
Application
Directions
|
|
45
ppb
|
90
ppb
|
|
1
|
3.8
oz.
|
7.7
oz.
|
ApplyWhiteCap
to the entire surface area of the pond.
Single Applications: Use the amount of WhiteCap
listed to give 45 to 90 ppb .fluridone in treated water.
Higher rates should be used for dense weed infestations,
for dif.cult-to-control species, and for smaller ponds
(less than 5 acres in size and average water depths of
less than 4 feet). Split or Multiple applications:
Use when dilution of the treated water is likely to occur.
Do not exceed 90 ppb per annual growth cycle. |
|
2
|
7.7
oz.
|
15.7
oz
|
|
3
|
11.8
oz.
|
23.4
oz.
|
|
4
|
15.7
oz.
|
31.4
oz.
|
|
5
|
19.5
oz.
|
35.0
oz.
|
|
6
|
23.4
oz
|
46.7
oz.
|
|
7
|
27.2
oz.
|
54.4
oz.
|
|
8
|
31.4
oz.
|
62.4
oz.
|
|
9
|
35.2
oz.
|
70.1
oz.
|
|
10
|
39.0
oz.
|
78.1
oz.
|
|
|
Vascular
Aquatic Plants Controlled by WhiteCap
|
|
Floating
Plants
|
Emersed
Plants
|
Submersed
Plants
|
Shoreline
Grasses
|
|
common
duckweed
(Lemna minor)
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spatterdock
(Nuphar luteum)
|
bladderwort
(Utricularia spp.)
|
paragrass
(Urochloa mutica)
|
|
|
water-lily
(Nymphaea spp)
|
common
coontail
(Ceratophyllum demersum)
|
|
|
|
common
elodea
(Elodea canadensis)
|
|
egeria,
Brazilian elodea
(Egeria densa)
|
|
fanwort,
cabomba
(Cabomba caroliniana)
|
|
hydrilla
(Hydrilla verticillata)
|
|
naiad
(Najas spp.)
|
|
pondweed
(Potamogeton spp., except Illinois pondweed)
|
|
watermilfoil
(Myriophyllum spp., except variable-leaf milfoil)
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|
Suggested bApplication Rates For Duckweed
75' x 75' Pond (.13) Acre 4 ft avg depth. - Amount required: 2 -
4 ounces
105' x 105' Pond (.25) Acre 4 ft avg depth. - Amount required: 4
- 8 ounces
148' x 148' Pond (.50) Acre 4 ft avg depth. - Amount required: 8
- 16 ounces
208' x 208' Pond (1.0) Acre 4 ft avg depth - Amount required: 16
- 32 ounces
Duckweed
Information Websites
Here
are some websites we recommend if you are looking for more information.
Washington State Department of Ecology
http://www.ecy.wa.gov/Programs/wq/plants/pla
ntid2/descriptions/lemmin.html
Lemna minor (lesser duckweed) and Lemna trisulca (star duckweed) Duckweeds
are among the world's smallest flowering plants. Individual lesser
duckweed plants are tiny, round, bright green disks, each with a single
root.
USDA.gov
http://plants.usda.gov/java/profile?symbol=LEVA
PLANTS Profile for Lemna valdiviana (valdivia duckweed) | USDA PLANTSA
PLANTS profile of Lemna valdiviana (valdivia duckweed) from the USDA
PLANTS database.: Kingdom Plantae – Plants Subkingdom Tracheobionta
– Vascular plants Superdivision Spermatophyta – Seed plants Division
Magnoliophyta – Flowering plants Class Liliopsida – Monocotyledons
Subclass Arecidae Order Arales Family Lemnaceae – Duckweed family
Genus Lemna L. – duckweed Species Lemna valdiviana Phil. – valdivia
duckweed
Wikipedia
http://en.wikipedia.org/wiki/Lemnaoideae
Lemnaoideae - Wikipedia, the free encyclopedia 24 May 2009 ... Duckweed
is an important food source for waterfowl and are eaten by humans
in ... Classification of the duckweeds in the family Lemnaceae is
... en.wikipedia.org/wiki/Lemnaoideae - Cached - Similar - Lemna -
Wikipedia, the free encyclopediaLemna is a genus of free-floating
aquatic plants from the duckweed family. .... Lemna Ecotox testing
Duckweed growth inhibition tests and standardisation ...
Guppies.com
http://www.guppies.com/forums/showthread.php/duckweed-and-waterquality-18686.html
Duckweed and waterquality... a blessing in disguise. In fact, duckweed
does much more than suck up every particle of Nitrate in your tank.
In depth study will reveal that duckweed attacks ammonia vigorously,
as well as Nitrates, Nitrites and just about any other molecule with
the nitrogen atom in it, lol. In addition to that, duckweed sucks
up phosphorus like a thin milkshake, actually removes suspended solids,
and organic material and even other toxins!. As if that weren't impressive
enough, it produces oxygen like nobodies business!
Homemade Duckweed Skimmer
http://forums.pondboss.com/
If you are looking for a homemade duckweed skimmer then we saw on
the PondBoss Forums of a fellow who used a "prickly rope"
that he rigged up using a simple nylon rope and zip-ties to create
an ingenious pond skimmer system that basically corrals the duckweed
and traps it in the circle of the "prickly rope" where it
can be easily removed. You have to see it to believe it and I bet
it works too!
Email us for information or with your questions.
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