Aquatic Plant Management Identifying and Managing Aquatic Vegetation Eric Stormer NAVFAC Atlantic
Aquatic Plant ManagementIdentifying and Managing Aquatic VegetationEric StormerNAVFAC Atlantic
Benefits of Aquatic VegetationAquatic Plant Management
Microscopic plants (phytoplankton)
Larger algae and flowering plants (macrophytes)
Provide habitat:FishFish food organisms
WaterfowlOther wildlife
Large plants support:
Oxygenation
Shoreline stabilization
Removal of pollutants, e.g., heavy metals
Aesthetics
The Problems of Excessive Aquatic Vegetation
Aquatic Plant Management
Recreation
Too much of a good thing…
Water Hyacinth impeding water flow on a river
Spartina grass
Aquatic Plant IdentificationAquatic Plant Management
Algae
Microscopic (AKA phytoplankton)Mat-forming (AKA filamentous algae)
Chara (AKA stonewort)
Microscopic (planktonic) algae
Blooms occur in water with abundant nutrients
Mat-forming (filamentous) algae
Form floating, mat like growths. Most common problem in ponds.
Chara (AKA Stonewort)
Flowering PlantsAquatic Plant Management
Flowering Plants
Curly-leaf pondweed
Submersed Plants – alternate leaf arrangement (one leaf per node)
Exotic invasive Grows best in spring, tends
to die out in summer
Sago Pondweed
Submersed Plants – alternateleaf arrangement (one leaf per node)
Very long, almost thread-like leaves 2” – 6” in length
Individual leaves tend to be somewhat curved
May be a weed in some situations
Seeds and underground tubers are valuable food for waterfowl
Leafy Pondweed
Submersed Plants – alternate leaf arrangement (one leaf per node)
Extremely common in ponds during summer
Bear very narrow leaves 1” – 2” in length
Southern Naiad
Submersed Plants - Opposite Leaf Arrangement (two leaves per node)
Leaves are not visibly spined
Bear two leaves per node, but sometimes appear to bear three
Leaves are typically flat, straight
Brittle Naiads
Submersed Plants - Opposite Leaf Arrangement (two leaves per node)
Leaves are stiff, slightly spined
Leaves are sometimes clustered at the tips of stems
Coontail
Submersed Plants – Whorled Leaf Arrangement (3 or more leaves per node)
Leaves are branches and spined
Plant is very lightly rooted, or floating in the water column
Very common in shallow, marsh-like areas and in older ponds
Eurasian watermilfoil
Submersed Plants – Whorled Leaf Arrangement (3 or more leaves per node)
Serious pest Spreads rapidly This species typically bears
more than 10 leaflet pairs per leaf, whereas native milfoils have fewer than 10
Each node bears 4 leaves Red to olive green stems
Submersed Plants Whorled Leaf Arrangement (3 or more leaves per node)
Watermeal Duckweed
Free-floating Plants
Looks like tiny green seed or green cornmeal
Has no roots Are found in nutrient-rich
waters
1/8” – 1/4” diameter leaves Bears a small root that
hangs in the water Are found in nutrient-rich
waters
Azolla
Water hyacinth
Rooted-floating PlantsBear underground stems (rhizomes) from which growth
occursLeaves and flowers float on the water surfaceGenerally found growing in water less than 4’ – 5’ deep Include waterlily, watershield, American pondweed, and
SpatterdockWatershield and American pondweed can be weedy in
the shallow areas of ponds and lakesSpatterdock and waterlilies provide valuable wildlife
habitat and should be protected in natural lake and wetland areas
Spatterdock, AKA cow lily
American pondweed
Watershield
Waterlily
Emergent PlantsAKA shoreline plants, marginal plants – in reference to where they occur
Includes grass-like (graminoids) and broadleaved plants
Grass-like plants include: cattails, bulrushes, spikerushes, and reed canarygrass
Broadleaved plants include: willow trees, creeping water primrose, and purple loosestrife
Many of these plants spread rapidly by underground stems (rhizomes), and by seed
Cattail
Phragmites
Spikerush
Bulrush
Creeping water primrose
Purple Loosestrife
Aquatic Plant Management Methods
Aquatic Plant Management
Consider the water’sDepthVolumeTurbiditypHFlowPrevailing winds direction
Preventive Control
Mechanical Control
Hydrilla verticillata removal
Biological Control
Habitat Alteration
Nutrient Management
Habitat Alteration
Nutrient ManagementHabitat Alteration
Light inhibitors, aerationHabitat Alteration
Benthic barrier
Drawing down the lakeHabitat Alteration
HerbicidesAquatic Plant Management
Chemical Control – EPA Registered products:Used in extremely low does in the water.
They do not persist very long (usually only a few days).
They do not bioaccumulate in the fatty tissues of humans or animals .
Before Using HerbicidesProperly identify the weed.Never apply chemicals in or around water unless they are specifically labeled for aquatic use.
Always follow any water use restrictions (for drinking water, livestock, irrigation, etc.).
Apply the correct dose.
Before Using HerbicidesMake timely applications. Late spring – when plants are young and growing actively – is usually the best time to apply herbicides. Later applications may result in fish kills, as water will be warmer, vegetation is usually dense/extensive, and oxygen levels are low.
Apply when the temperature is correct; herbicides do not affect aquatic plants when the water is too cold.
Before Using HerbicidesRemember – some herbicides are contact based; can be applied as spot treatments for quick kill. Others are translocated; will work but take longer.
Retreat as required. Most aquatic herbicides have no effect on seeds and underground structures that lie dormant over winter.
Consider the following - Herbicides:Expense Available time frame for controlApplication typeFormulationLabel informationVegetation decayLicenses
Aquatic Weed Herbicide Typical Dose1 Restrictions2
Algae (microscopic, mat-forming, Chara)
copper sulfate (25% Cu) 2 7 lbs/A-ft Do not use in trout- or koi-bearing waters
copper chelates Dose varies by formulation Do not use in trout- or koi-bearing waters
sodium carbonate peroxyhydrate (GreenClean®, Phycomycin®) 3-100 lbs/A-ft None, but check specific labels
endothall (Hydrothol 191®)
liquid form 0 6-18 pt/A-ft I, L, D = 7-25 days
granular form 3-81 lbs/A-ft
Subm ersed plants (pondweeds, naiads, elodea)
endothall (Aquathol K®)
liquid form 0 6-3 2 gal/A-ft I3, L, D = 7-25 days
granular form 2 2-22 lbs/A-ft I, D = 7 days
diquat (Reward®) 0 5-2 gal/SA I = 1-5 days; D = 1-3 days; L = 1 day
fluridone (Sonar®, Avast! ®)
Dose varies by formulation I = 7-30 days Do not apply within a quarter mile of potable water intakes4
Subm ersed plants (Eurasian watermilfoil, coontail)
2,4-D
Navigate® 100-200 lbs/SA I, D Note precautions on label DMA 4 IVM® Up to 2 8 gal/A-ft
triclopyr (Renovate®)
0 7-2 3 gal/A-ft
D Note setbacks when applying near potable water intakes
fluridone (Sonar®, Avast! ®)
Dose varies by formulation
I = 7-30 days Do not apply within a quarter mile of potable water intakes4
Free-floating plants
(duckweed, watermeal)
diquat (Reward®) 1-2 gal/SA (add surfactant) I = 1-5 days; D = 1-3 days; L = 1 day
fluridone (Sonar AS®, Avast! ®)
0 12-0 24 qt/A-ft I = 7-30 days Do not apply within a quarter mile of potable water intakes4
Rooted-floating plants (waterlilies, spatterdock)
Glyphosate (AquaMaster® and others plus surfactant, Glyphomate 41® without added surfactant)
Dose varies according to species Consult label
Do not apply within a quarter mile upstream of potable water intakes
Em ergent plants (cattails, willows, grasses and
other perennial plants)
Glyphosate (AquaMaster® and others plus surfactant, Glyphomate 41® without added surfactant)
Dose varies according to species Consult label
Do not apply within a quarter mile upstream of potable water intakes
Questions?