Common Aquatic Plants: Identification, Control Options and More! · 2017. 5. 12. · aquatic plants •Extremely fast acting –Plant die off in a matter of days •Short half-life

Common Aquatic Plants:

Identification, Control Options

and More!

Nate Karsten

Environmental Biologist

PLM Lake & Land Management Corp

PLM Lake & Land

Management Corp

• Southern Regional Manager, 15 years experience

• Graduate of Grand Valley State University – Focus on Environmental Biology & Aquatics

• PLM has been managing water bodies since 1979

• Full Service Management Company

Aquatic Herbicide & Algaecide Applications

Permitting

Mechanical Weed Harvesting

Water Quality Monitoring

Aquatic Vegetation Mapping

Fountains and Aeration

Bathymetric Mapping

• Part 1 – Aquatic Plant Types

• Part 2 – Chemical Control Options

• Part 3 – Permitting

• Part 4 – Phosphorus Removal

Overview

• Algae

• Submersed Plants – Exotic & Native

• Floating Plants

Aquatic Plant Types

Accurate identification is

essential for proper

management!

• Filamentous

– Free floating algae of many species

• Planktonic

– “Pea soup”

• Macroalgae

– Chara

– Starry Stonewort

Algae

Algae

Submersed Weeds

• Exotic

• Public enemy #1 on Michigan lakes

• Highly invasive, forms a canopy & monoculture

• Spreads from root system, seed, and fragmentation (cutting & raking increases spread)

• Outcompetes native plants

• Leaflets in whorls of four

• Visible red tip

Eurasian Water Milfoil

Curlyleaf Pondweed

• Exotic

• Overwinters under ice

• Typically the first plant

present in spring

• Natural die off mid summer

• Small, serrated “teeth” on leaf

margins

• “Lasagna noodle” leaf

• Reproduction via turions

• Treatment prior to turion

production

Cabomba (Fanwort)

• Exotic

• Aquarium Plant

• Spreading in southern

Michigan, especially the

Delton, Vicksburg,

Kalamazoo areas

• BRIGHT green coloration

• Leaves are opposite pairs

• Bright white flower

Thinleaf Pondweeds

• Several species;

Threadleaf, Sago, Fries,

Vasey’s, etc…

• Native

• Common to small ponds

• Slender stems and

leaves, often resembling

pine needles

• Largeleaf, Variable, Illinois, Naiad, Water Lilys, etc

• Typically do not cause problems

• Fundamental component of aquatic ecosystems

• Perform important functions – Stabilizing sediments

– Support aquatic insects

– Maintaining Oxygen

– Provide forage and refuge areas for fish

Other Native Aquatic Plants

Coontail • Lacks true roots

– ‘Anchors’ to the bottom

• Draws nutrients directly from

the water

• Forked leaflets

• Leaves are closer at the ends

of branches, creating a

‘raccoon tail’ appearance.

• Often confused with Eurasian

water milfoil and Cabomba.

Coontail

• Typically associated with eutrophic

waters

• Can become an issue in lagoon

systems.

• Mats of coontail can be quite dense

and prevent light penetration

• Obtains nuisance levels June

through August

Free-Floating Plants

Watermeal

• Free floating – Moves with wind and wave

action

• Nutrient driven growth

• Small water bodies can be quickly covered over

• Worlds smallest flowering plant

• Often found coexisting with duckweed

Duckweed

• A number of species

– Small, Great, Forked

• Round to oval shaped leaves,

called fronds

• Each frond has one root

• Multiplies through budding

• Often associated with

eutrophic waters

• Over winter, small winter buds

rest on the sediment and

return to the surface in spring

Duckweed

• Free floating

– Moves with wind and wave

action

• Nutrient driven

– Draws nutrients from the

water column for growth

• Small, stagnant water bodies

can be quickly covered over

Duckweed

• Prevents light penetration

• Excellent water filter; takes up

phosphorus, nitrogen, carbon,

etc…

– BUT… It doesn’t process it

• Unless it is skimmed off,

duckweed will release

everything back into the

system.

Duckweed

• Important to treat Late

May through Early

September

• Approximately once

monthly

– Sometimes more

– Often times less

• Just a handful of products registered for aquatic use

• Products are species specific

• Systemic vs. Contact Herbicides

Chemical Control

• Prescription drugs (antibiotics)

are therapeutic if taken in

small doses, but can be

dangerous if abused or taken

in overdose proportions.

• Pesticides, like antibiotics are

effective when used in the

right circumstances, but can

become a threat to the

environment or even human

health if improperly used.

Less Toxic LDC/50 mg/kg

Fluridone 10,000

Glyphosate 5,600

Table Salt 3,000

Triclopyr 2,574

Aspirin 1,000

2,4-D 300 – 1,000

Copper Sulfate 300

Diquat 230

Caffeine 192

Nicotine 53

Sodium Cyanide 6.4

Most Toxic

Dose Makes the Poison

• Fluridone $$$ • Expensive

• Persists in the water column all season

• Not suitable for lagoons that discharge as product will be lost

Chemical Control

• Flumioxizin $$ • Contact herbicide, kills only plants it

comes in contact with

• Newest active ingredient in aquatics

• Provides excellent control of duckweed as well as a broad range of other aquatic plants

• Extremely fast acting – Plant die off in a matter of days

• Short half-life (~1.5 days)

Chemical Control

• Diquat dibromide $ • Contact herbicide, kills only plants it

comes in contact with

• ‘Old school’ control method – Still effective!

• Viable option for most submersed plants (i.e. Coontail, EWM, Curlyleaf, etc…)

• Short half-life (~2 days)

Chemical Control

• Rotation and combination of products may offer the best results – Products are species and ‘rate’ specific

• Treatment methodology – Foliar spray via boat or truck mounted spray system

– Ideally when plants are stacked up on one end of the lagoon

• Seasonal treatment requirements utilizing contact herbicides – Duckweed/Watermeal

» 3-5 treatments throughout the growing season

– Submersed plant growth (EWM, Curlyleaf, Coontail, etc…)

» 1-2 treatments throughout the growing season

• Consulting with a trained and licensed applicator is key

Chemical Control

• Fluridone $$$ • Effective for inland lakes, not viable for lagoons

• Flumioxizin $$ • Recommended control method for Duckweed/Watermeal

• Useful for controlling most other submersed plants as well

• Diquat dibromide $ • Cost saver when targeting submersed plants (i.e. Coontail)

Chemical Control Summary

• Permitting through MDEQ MiWaters site is a must! – PLM can assist with the permit process

Permitting

• NPDES permit number

• Chemical MSDS Sheets & Labels

• Proposed discharge concentration

Permitting

• Product half-life in water • Discharge frequency • Outfall

• Water treatment additive function

• Amount of product to be applied

• Date(s) of application

Permitting

• Date of discharge

• Water volume, depth and acreage

• Lagoon map

• In situations where wastewater authorities do not have the means to install permanent treatment systems, alternatives are available

• Have successfully applied batch treatments of Aluminum Sulfate for the precipitation of Phosphorus prior to lagoon discharge, bringing levels under the 1 ppm maximum

• It is possible!

• Jar testing necessary to determine ideal treatment amounts

Phosphorus Removal

Successful Weed Management

• Thornapple Township • Duckweed treatment & Phosphorus precipitation applications

• Houghton Lake Sewer Authority • 56 acres of finishing ponds treated for abundant coontail

• Village of Mesick

• City of Manton

• Camp Thornapple Lagoons

• Shanty Creek Wastewater

• Schuss Mountain Wastewater

• Butman Township

Thank You!

Nate Karsten

[email protected]

(616) 891-1294 x2008