Transcript Document
Integrated Pest Management
& Certification Training
Aquatic Weed Management
Richard D. Lee, Ph.D.
IPM Specialist
Bureau of Land Management
Aquatic Plants
In natural systems such as lakes and
ponds, light to moderate growths of
aquatic plants serve useful purposes:
Provide
oxygen, food and cover for fish
and other aquatic organisms, and may
stabilize bottom sediment.
Aquatic Plants
In overabundance, many species become
“weedy” as they crowd out desirable plants,
adversely affecting other aquatic life and our
ability to use the water:
Recreation
Creation of foul odors and discoloration
Fish kills
Blockage of water flow
Aquatic Weeds
My goal this morning is to provide you
with the necessary background
information to allow you to understand
the procedure for developing an aquatic
weed management plan.
Classification of Aquatic
Weeds
Two groups of aquatic plants:
1. Algae - simple plants without roots, leaves
or stems.
They reproduce by cell division,
fragmentation, or by spore formation.
2. Vascular plants - plants having roots, stems,
leaves, and flowers.
There are four classes - submersed, freefloating, rooted floating, emerged plants.
Aquatic Weeds - Algae
Three types:
1. Microscopic algae - single celled or colonial
algae. Also referred to as “Phytoplankton”
when suspended in water. During the
daylight - give off oxygen, During night remove oxygen.
If overabundant - fish kill due to oxygen
removal from water - referred to as an
“algal bloom” - the result of too much
fertilizer in pond.
Aquatic Weeds - Algae
Three types:
1. Microscopic algae
2. Filamentous algae - thread-like filaments
that form mats on surface of the pond. As
algae photosynthesize, oxygen gets trapped in
the body causing them to rise to the surface as
clumps.
Examples:
- Spirogyra - bright green and slimy
- Cladophora - cotton mat algae, due
to texture
- Pitophora - horsehair coarse
Aquatic Weeds - Algae
Three types:
1. Microscopic
2. Filamentous
3. Chara - looks more like a plant with leaves
needle-like and arranged in whorls
along the “stem”.
Musky odor and gritty surface due to
calcium deposits. Also called
“stonewort”
Submersed
Plants
Aquatic Weeds - Vascular
Plants – Submersed Plants
Four Groups:
1. Submersed plants - rooted to the bottom
and completely submersed except for
flowers which may extend above the
water. Often referred to as “moss”.
Identification based upon:
* Leaf arrangement
* Leaf shape
Aquatic Weeds - Vascular
Plants
Submersed Plants - Alternate Leaves:
One
leaf per node
PONDWEEDS - (Potamogeton sp.)
Curly Leaf Pondweed
Sago Pondweed
Leafy Pondweed
Aquatic Weeds - Vascular
Plants
Submersed Plants - Opposite Leaves:
Two
leaves per node
NAIADS (Najas sp.)
Southern naiad
Brittle naiad
Aquatic Weeds - Vascular
Plants
Submersed Plants - Whorled Leaves:
Three or more leaves per node, arranged in a whorl.
Most serious submersed aquatic plants fit in this
group.
Examples:
COONTAIL - Ceratophyllum demersum
AMERICAN ELODEA - Elodea canadensis
EURASIAN WATERMILFOIL - Myriophyllum
spicatum There are other watermilfoils,
including parrotfeather.
HYDRILLA - Hydrilla verticillata
Got to Know Your Weeds:
Eurasian Watermilfoil
Eurasian Watermilfoil
Myriophyllum spicatum
Submerged, rooted
perennial.
Grows in depths of up to
15 feet deep.
Forms dense mats.
Got to Know Your Weeds:
Parrotfeather
Parrotfeather
Myriophyllum aquaticum
Submerged, rooted
perennial.
Forms dense mats.
Whorled leaves.
Got to Know Your Weeds:
Hydrilla
Hydrilla
Hydrilla verticillata
Forms dense mats.
Aquatic Weeds - Vascular
Plants – Free Floating
Four Groups:
1. Submersed plants
2. Free-floating Plants - these plants live
unattached to the soil. There are
roots, extend only in the water for
nutrient uptake.
Majority of the plant is flattened or
boat- shaped clusters of leaves with
short segmented stems.
Free Floating
Aquatic Weeds - Vascular
Plants
Free-floating Plants:
Examples:
DUCKWEED - (Lemna sp.) - 0.5” across,
with 2 to 4 leaves.
WATERMEAL - (Spirodela sp.) - 1/16”
diameter
GIANT SALVINIA – (Salvinia molesta)
WATER HYACINTH - (Eichhornia crassipes)
- major aquatic weed of concern
Got to Know Your Weeds:
Giant Salvinia
Giant Salvinia
Salvinia molesta
Native to South America
First found in U.S. in 1995 in
South Carolina.
Now found in 24 watersheds
in Texas, California, Arizona,
Louisiana, Mississippi,
Alabama, Georgia, &
Florida.
Southern States most
susceptible.
Got to Know Your Weeds:
Giant Salvinia
Giant Salvinia
Salvinia molesta
Forms dense mats.
Got to Know Your Weeds:
Water Hyacinth
Water Hyacinth
Eichhornia
crassipes
Aquatic Weeds - Vascular
Plants – Rooted Floating
Four Groups:
1. Submersed plants
2. Free-floating Plants
3. Rooted Floating Plants - also referred to as
“Emersed Weeds” on some labels.
Plants are rooted in the bottom sediments
in shallow water. Leaves are floating or
erect.
Plants identification by leaf shape and
petiole attachment.
Rooted Floating
Aquatic Weeds - Vascular
Plants
Rooted Floating Plants:
Center Attachment
of Petiole
WATER LOTUS
WATERSHIELD
Cleft
or Edge Petiole Attachment
WATER LILY
SPATTERDOCK
Aquatic Weeds - Vascular
Plants – Emergent Plants
Four Groups:
1.
2.
3.
4.
Submersed Plants
Free-floating Plants
Rooted Floating Plants
Emergent Plants - Most of the plant is
above the water surface.
Common Examples:
Purple Loosestrife
Salt Cedar
Emergent Plants
Got to Know Your Weeds:
Purple Loosestrife
Aquatic Weeds - Management
Remembering our four step approach to
weed management will assist in
developing a management plan for
aquatic weeds:
1.
Prevention
2. Early Detection
3. Timely Management
4. Site Rehabilitation
Aquatic Weeds - Management
Prevention:
We
need to be aware of the potential threat
aquatic weeds have for our areas and
learn to recognize those weeds of concern.
Giant Salvinia - is a problem in Texas and has
the potential to make it into this area.
Purple Loosestrife - a serious problem in the
Eastern portion of the U.S. and moving our
way.
Aquatic Weeds - Management
The key here - is
we need to be
looking at what is
growing in our
ditches and lakes.
Aquatic Weeds - Management
Early Detection:
Timely Management:
Biological
Mechanical
Cultural:
Proper construction – steep slopes – keep
water moving
Draining/Drying – species dependent
Use
of Herbicides
Aquatic Weeds - Management
Timely Management:
Biological
- the use of living organisms to
manage other living organisms.
Limited options available.
Tilapia – plant eating fish
White Amur – plant eating fish, concerns
regarding its environmental impact.
Mechanical
Cutting, Mowing, Raking, Digging
Aquatic Weeds - Management
Herbicides Available:
– Copper sulfate
Submersed – Diquat, Endothall, Fluridone,
2,4-D
Free Floating – Diquat,
Emersed – Glyphosate, Triclopyr
Algae
Aquatic Weeds - Management
Use of Herbicides - before using a herbicide,
make sure you have answers for the
following questions:
1. What is the use of the treated water?
2. Characteristics of the Environment
3. Characteristics of the Water
4. Characteristics of the Selected Herbicide
Aquatic Weeds - Management
Herbicides and Static Water:
Floating and emerged weeds are easy to manage.
Submerged weeds and algae not real difficult.
Herbicides and Flowing Water:
Floating and emerged weeds are still easy to
manage.
Submerged weeds and algae can only be
managed effectively through continuous
application at a particular point to maintain a
specified level of herbicide concentration - it’s not
easy.
Aquatic Weeds - Management
Application of Aquatic Herbicides:
1. Application equipment - is it in good working
order.
2. Determine area to be treated:
Aquatic Situation
Determining Treated Area
----------------------------------------------------------------------- Algae
Water Volume - acre -ft
Submersed Plants
Water Volume - acre-ft
Free-Floating
Surface Area - acres
Rooted Floating Plants
Surface Area - acres
Emergent Plants
Surface Area - acres
Aquatic Weeds - Management
Application of Aquatic Herbicides -
Pond:
Surface Area:
Free-floating, rooted-floating, and emerged
weeds
Two dimensional - length X width
Rate of herbicide application based upon
“amount/acre”
Aquatic Weeds - Management
Application of Aquatic Herbicides - Pond:
Water Volume:
Algae and submerged
Three dimensional - length X width X depth
Rate of herbicide application based upon
“amount/acre-ft” or “ppm” (Parts per million).
To convert “ppm” to “lbs. product required”
2.7 X PPM wanted X acre-ft = lbs. Prod.
Req.
Aquatic Weeds - Management
Application of Aquatic Herbicides - Canal/Moving:
Herbicide application depends upon:
Water Volume: Average width X Average depth
= sq. ft.
Flow Speed: Distance water moves per unit of time
= ft/sec
FLOW RATE: Water volume X Flow Speed
= cubic feet/sec
Aquatic Weeds - Summary
1. Different Types of Weeds:
Algae
Submersed Weeds
Free-floating Weeds
Rooted Floating Weeds
Emergent Weeds
2. Management Plan Development