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