Controlling Aquatic Plants

When left uncontrolled, aquatic plants• Impair recreational uses• Cause foul odors and bad taste to

drinking water• Cause fish kills• Stunt fish growth• Reduce water depth as plants die• Increase nuisance insect populations• Decrease property values• Cause accidental drowning• Block water flow in irrigation and

drainage ditches

A problem when vegetation coversmore than 20-

25% of shallow area

more than 50% of a body of water

Two groups of aquatic plants

Algae

Flowering Plants

Algae

• Microscopic algae (phytoplankton)

• Filamentous algae(moss)

• Chara(stonewart)

Flowering plant categories

• Emergent plants

• Rooted floating plants (emergent)

• Free floating plants

• Submersed plants

Emergent plants•rooted in

sediment•most of foliage

above water•cattails,

bulrushes, willows

•most “wetland” plants are emergent

©USDA, NRCS @ PLANTS

© USDA, NRCS @ PLANTS

© USDA, NRCS @ PLANTS

© USDA NRCS, 1995 Midwestern Wetland Flora @ PLANTS

© USDA NRCS, 1995 Midwestern Wetland Flora @ PLANTS

Rooted floating plants

• lilies, spatterdock

•rooted in sediment

• leaves and flowers float on water surface

© USDA, NRCS

Free floating plants

•duckweed, water meal

•not rooted in sediment

•freely float in water

© USDA, NRCS, 1997 Northeastern Wetlands Flora @ PLANTS

Submersed plants• elodea,

pondweeds• rooted in

sediment• only flowering

structure emerges above water surface

© USDA, NRCS, 1997 – Northeastern Wetlands Flora @ PLANTS

© NRCS @ PLANTS

Pond Management–What’s your goal?

•Recreational fishing•Swimming & boating•Wildlife habitat / aesthetics•Livestock water supply•Aquaculture•Storm water management

Aquatic Plant Control – Physical

• Benthic barriers• Drawdown• Mechanical removal• Dredging• Dyes

Aquatic Plant Control – Biological• Grass carp

Aquatic Plant Control – Chemical

• Identify the problem plant• Use only EPA registered and

approved products• Read and follow all label

directions• Timing

– late spring, early summer• Temperature

– Over 65°• Retreat?

Calculating treatment areaHerbicide applications made on two parameters–

•Surface area basisfor control of rooted floating and emergent plants

•Volume basisfor control of algae and submersed plants

Surface area• Rectangular area

acres = length (ft) x width (ft)43,560 ft2

• Circular area (radius measured in feet)

acres = 3.1416 x radius2

43,560 ft2

• Triangular areaacres = ½ base (ft) x height (ft)

43,560 ft43,560 = number of square feet per acre

Depth

• Measure – don’t assume

• Measure at intervals, average together

Volume

Acre-feet = surface area (acres) xaverage depth (ft)

Example:Area = 240 ft x 120 ft

43,560 ft = 0.66 acreAverage depth = 2+4+9/3 = 5 ftVolume = 0.66 acre x 5 ft =

3.3 acre-ft

Amount required

Pounds required = 2.7 lb x ppm desired x acre-ft

(from label)

Example:Required dose is 2 ppm.

Amount = 2.7 lb x 2 ppm x 3.3 acre-ft

= 16.2 lb of product

PermitsPrivate applicator permit

Purchase and apply restricted-use pesticides to privately owned lake or pond, or drainage ditch.

Commercial application of pesticides (for hire) requires a commercial license, Category 5.

For information on pesticide permits contact Office of Indiana State Chemist 765/494-1492

IDNR permitA permit from IDNR is required

when

• a lake resident treats more than 625 sq. ft; more than 25 linear ft along shore and in water deeper than 6 ft.

• a biological organism (grass carp) is used to control plants.

• mechanical control is used in areas larger than 625 sq. ft.

IDNR permit

• Obtained from Division of Fish & Wildlife

• $5 filing fee

• IDNR Fish & Wildlife402 W. Washington St., Rm. W273Indianapolis, IN 46204317/232-4093