Aquatic Plant Management2017
Gary Burtle
University of Georgia
Animal & Dairy Science
Types of Aquatic Plants
• Algae- Filamentous, Planktonic, Rooted
• Vascular (macrophytes)
– Floating, or with floating leaves
– Submerged
– Emergent
– Woody
Planktonic & Filamentous Algae
Lyngbia
(Blue green)
Spirogyra (green algae)
Other Filamentous AlgaeExamine at 200X for identification of filamentous algae
Pithophora
Hydrodictyon
Blue-greens and Euglena
MicrocystisEuglena
Potentially toxic algal
scumRed algal scum
Or green scum
Rooted Algae
(Chara and Nitella)
Floating weeds and Weeds
with Floating Leaves
Duckweed & Water Meal
Roots = Duckweed
Watermeal
Floating weeds/with floating
leaves
Brasenia – Water shield
Nymphaea- White water lily
Water HyacinthEichhornia crassipes
Giant SalviniaSalvinia molesta, Salvinia biloba, Salvinia herzogii, Salvinia minima,
Salvinia auriculata
Common Salvinia
Smaller than your thumbnail
and with separated leaf-hairs
SUBMERSED AQUATIC
PLANTS
Submerged: Southern naiad
Submerged: Coontail
Variable-leaf Milfoil
ParrotfeatherMyriophyllum aquaticum
Submerged: Pond weed
Potamogeton and Stukenia
Floating leaf, American,
Illinois
Sago
Stukenia
Diversified leaf
Curly leaf, P. crispus
Bladder Wort (carnivorous)
Form with floating leaves
Cabomba (Fan Wort)
Emergent: Maidencane
TopedograssPanicum repens
Emergent: Slender spikerush
Proliferating form is submerged or
forms dense mats. Grass carp will
control this plant.
Emergent: Primrose (Ludwigia sp.)
Grows from the shore into the pond.
Leaves vary from round to slender,
opposite or alternating. Yellow flower.
Other Emergent Plants
Smartweed
Cattail
Rush
Woody Plants
Willow
Cypress
Groundsel
bush
Alder
How to Manage Aquatic Weeds
• Start early
• Get proper identification
• Select proper control
• Apply control effectively
• Repeat control when necessary
• Do not fertilize weed infestations…
– …control with herbicide or grass carp first.
Maintenance Programs
• Chemical Treatment
• Biological Control
• Water Testing and Observation
• User Education
Spot Treatments
• WHEN YOU SEE THE FIRST WEEDS
• Apply to foliage of target plants
• Use granular chemical formulations
• Use an adjuvant
• You Must Start
the Treatment Early
• Contact– Copper – algae (powder or liquid)
– Sodium percarbonate - algae
– Diquat – contact herbicide (Reward)
– Endothal – contact herbicide (Aquathol, Hydrothol-191)
• Systemic– For Emergent Weeds
• Glyphosate (Rodeo) – grasses, shoreline
• Imazapyr – emergent weeds (Habitat)
– For Submerged Weeds• Floridone (Sonar) – residual herbicide
• 2,4-D – growth regulator (use granular form)
• Triclopyr – brush (Renovate) (use granular for submerged weeds)
• Imazamox (Clearcast) broad spectrum
• Penoxsullam (Galleon) Floating plants and submerged
– For Floating Weeds
• Carfentrazone (Stingray) duckweed
• Clipper (flumioxazin) watermeal, duckweed, filamentous algae
Watermeal and Duckweed
• Depends on applicator skill
• Diquat:Cutrine plus tank mix
– Less expensive than diquat alone, but need to
repeat until control is achieved
• Clipper
– Good for acid water conditions
• Fluridone
– Pour in for those with limited equipment ability
Grass Carp Stocking In Georgia
• Use only Triploid Grass Carp
• Stock at 5-10 per acre before weeds start
to grow
• Use 20 to 40 per acre for existing weed
problems
• Use 50 or more per acre if algae is a
problem (copper resistant species)
• Use spillway fences
One Pound and 14 inches
Limits of Grass Carp
• Effective for about 6 years
• Large carp do not eat aggressively
• Grazing is a slow control method
– May take 3 or more years without chemical
assistance
• Heavy grass carp stocking can interfere
with bream spawning activity
WEEDS GRASS CARP AVOID
• Water lily
• Cabomba (fanwort)
• Lemon bacopa
Alligatorweed Flea Beetle
• Pre release, 1963, 97,000 acres of
problem alligatorweed
• 1981, less than 1,000 problem acres of
alligatorweed
• Now comes
and goes
Water Hyacinth Weevil
• Stocked by USACE
since 1972
• Comes and goes as
hyacinth repopulates
• 90 to 120 day life
cycle
Salvinia Weevil
Salvinia molesta or Salvinia minimaMay work in south Georgia since winter survival is a concern in north Georgia.Need a salvinia weevil growing location.
Pond Drawdown
• May work for LARGE LAKES
• Need some areas of deep water for fish
refuge
• Only draw down in the WINTER time
• Expose bottom for at least ONE MONTH
• Spray exposed weeds when they are
green
• Repeat every three or four years
Resistant to Drawdown
• Bladderwort, Hydrilla, Illinois pondweed,
Chara, Variable leaf milfoil– Have drought resistant seeds, rhizomes, etc.
• Alligatorweed, Arrowhead, Bulrush,
Maidencane, Pickerelweed, Smartweed,
Spikerush, Water Hyacinth– Marginal or floating plants
The “Bloom”
• Algae, phytoplankton, that shade the pond
bottom by absorbing light (<3 feet deep)
• Established by using a fertilization
program
• Or, after weed control,
Phosphorus is released
from decomposing weeds
Integrated Aquatic Plant
Management1. Identify intended uses and plants that
hinder these uses
2. Understand the plant ecologies
3. Set management goals
4. Consider management methods
5. Develop an Action Plan
6. Use a long term education program