Aquatic Plant and Algae Management

Transcription

1 Aquatic Plant and Algae Management for Ohio Ponds Eugene Braig, Program Director, Aquatic Ecosystems OSU Extension, School of Environment and Natural Resources

2 Some Pond Management References Austin, M. et al Ohio pond management handbook: a guide to managing ponds for fishing and attracting wildlife. Ohio Department of Natural Resources, Division of Wildlife, Columbus, OH. wildlife.ohiodnr.gov/species-and-habitats/pondmanagement Many older pond-management fact sheets available via correspondence (revisions pending): braig.1@osu.edu Occasional newsletter articles: senr.osu.edu/yourpondupdate

3 Some Pond Management References Aquatic-plant specific Valuable resource for ID and management recommendations: Texas A&M: aquaplant.tamu.edu/ OSU Extension s classic summation by fact sheet: Lynch, W. E. Jr Chemical control of aquatic plants in ponds, extension fact sheet A School of Environment and Natural Resources, Ohio State University Extension, Columbus, OH. Purdue Extension s classic summary publication: Lembi, C. A Identifying and managing aquatic vegetation, publication APM-3-W. Botany and Plant Pathology, Purdue University Extension, West Lafayette, IN.

4 Aquatic Plant Management: The Outline Prevention of related problems Management: Mechanical/Harvest Pre-application Aquatic herbicide overview Grass Carp

5 Aquatic Plant Management: The Outline Prevention of related problems Management: Mechanical/Harvest Pre-application Aquatic herbicide overview Grass Carp

6 Successful pond management Nutrient management In freshwater aquatic systems, phosphorus (P), tends to be rare and thus is the primary limiting nutrient. Little phosphorus = few problems.

7 Prevention: Nutrient management Nutrient management: Recognize and manage external sources of nutrients from within the watershed. Apply fertilizers conservatively, avoiding phosphorus. Maintain septic systems. Make Canada Geese unwelcome to small ponds. Tolerate stands of terrestrial and wetland vegetation. Do you think Columbus OH s Schiller Park has a large goose population (Eugene Braig 2015)?

8 Prevention: Nutrient management Nutrient management: Manage internal availability/recycling of nutrients. Apply alum or other precipitating chemical agents as necessary (acidifier, so buffer with lime as necessary). Aerate! Tolerate appropriate coverage of submerged vegetation within pond. Do you think Columbus OH s Schiller Park has a large goose population (Eugene Braig 2015)?

9 Prevention: Nutrient management ( where DO is dissolved oxygen) The phosphorus (P) cycle in lakes/ponds (Kalff, 2002).

10 Prevention: Nutrient management Diffuser aeration: Minimizes the internal recycling of available phosphorus. Promotes beneficial bacteria that reduce the accumulation of organic muck. Entrains harmful-algal-bloom organisms, reducing competitive advantage. Ordinarily seasonal operation (warm months only). Can be repurposed to reduce risk of winter fish kills. (National Pond Service)

11 Prevention: Nutrient management A trial aeration prescription for small ponds: How many? Ideally, 2 3 diffusers per acre positioned along deep water. How much? Estimate pond volume: i.e., surface area x average depth. Check manufacturer specs: Published recommendations span wide range: hours for one complete turnover of pond volume. Relatively common objective: turn over pond volume twice per day (i.e., 12 hours/turnover).

12 Prevention: Nutrient management Implement any aeration program (and, really, any large-scale change in management) when waters are cool, namely early in the spring. Disrupting waters that have already strongly stratified for the season has the potential cause premature turnover, oxygen crash, and a summer fish kill. Ideally, fire up system in the spring, run all day every day throughout warm months, and shut down in autumn.

13 Aquatic plant tolerance (Donald Cameron 2015) Tolerate the appropriate coverage of diverse vegetation. It s your pond; what constitutes the appropriate coverage is yours to determine. Ordinarily 5 20% in ponds with fisheries considerations (higher is possible for ponds without fisheries and much higher is possible for ponds without fish).

14 Aquatic plant tolerance Some additional benefits of aquatic plants: A more stable oxygen source. Beneficial competition for excessive nutrients. Provide additional habitat for the colonization of beneficial bacteria. Stabilize substrates. Provide habitat for invertebrates.

15 Aquatic plant tolerance Some negatives of aquatic plants in ponds: Seasonal die-offs (easily mitigated). Excessive coverage wide oxygen fluctuations. Excessive coverage reduced fish growth all round. Maintaining the right coverage is likely to take a commitment of active management effort.

16 Aquatic plant tolerance Managing aquatic plants to benefit a fishery and water quality: Construct pond with sufficient depth and slope to keep plant productivity restricted to the shallows: Maintain diversity of native submerged plant species for stability of functions. Use dyes as necessary to limit productivity in deep water. Spot treat with chemical herbicides as necessary to maintain stands of vegetation at desired coverage.

17 Aquatic Plant Management: The Outline Prevention of related problems Management: Mechanical/Harvest Pre-application Aquatic herbicide overview Grass Carp

18 Aquatic Plant Management: The Outline Prevention of related problems Management: Mechanical/Harvest Pre-application Aquatic herbicide overview Grass Carp

19 Pre-application considerations: pond-use restrictions Waiting periods based on pond use: e.g., fishing, domestic use, livestock watering, or irrigation. Ensures that the public will not come into contact with a herbicide at potentially harmful concentrations. Restrictions vary among herbicides, depending on the dosage and the persistence of the compound in the water. Always read label!

20 Pre-application considerations: Amount of area/volume treated Whole Pond: Late spring is the best time: May and June. Plants are young, still actively growing, and most susceptible. When water temperature reaches 60 o F. Estimate volume (surface area x average depth = volume in acre-feet). Follow label recommendations for application rate by volume treated.

21 Pre-application considerations: Amount of area/volume treated Spot Treatment: Recommended when water temperatures exceed o F. Granular formulation preferred: can be applied locally. Treat no more than 20 30% of the total area at a time, and no more than one treatment every 2 3 weeks. Reduces the chance of oxygen crash and fish kill. Warm water holds less oxygen. Loss of vegetation deprives the pond of its major oxygen source. Decomposition of dying plant material uses large amounts of oxygen. Can run out of oxygen in the early morning hours.

22 How an Herbicide Works Contact herbicides: Kills the part of the plant contacted by the spray. Good for spot treatments but thorough coverage of plant essential. Relatively fast-actng. Systemic herbicides: Absorbed by the foliage and translocated throughout the plant to stems, roots, and underground storage tissues. Good for killing plants with well-developed perennial root systems. Tend to work more slowly than contact herbicides.

23 Plant ID: Growth form Emergent Plant Rooted, Floating Plant Free-Floating Plant Algae Submersed Plant (Be aware: If you use aquaplant.tamu.edu the Texas A&M authors lump rooted, floating plants with emergent species.)

24 Growth forms: Emergent Management (especially large-scale) is most similar to terrestrial plants: Large monotypic stands may be targeted. Herbicides applied directly to foliage. Applications typically to precisely defined area. Concerns for selectivity may reduce number of available products. Photo credits: Texas A&M Extension (aquaplant.tamu.edu) & OSU Extension (go.osu.edu/gledn). Aquatic Plant Management Society (APMS 2014)

25 Growth forms: Floating-leaved Photo credits: Texas A&M Extension (aquaplant.tamu.edu) & OSU Extension (go.osu.edu/gledn). Herbicides often applied directly to foliage, similar to emergent plants and terrestrial crops. Frequent spot applications for selective control among desirable plants. Injection into water for root uptake becoming more common. APMS (2014)

26 Growth forms: Free-floating (e.g., duckweeds/watermeal and waterferns) Historically, limited options for duckweeds (mainly fluridone with limited response to diquat) and watermeal was simply considered difficult. Recently approved products also effective on duckweeds and flumioxazin in particular on watermeal. Photo credits: Texas A&M Extension (aquaplant.tamu.edu).

27 Growth Forms: Submerged Management most strikingly different from terrestrial: Entire water column often treated (whole-water treatment). Exposure measured in hours days for contact herbicides and Weeks months for some systemic herbicides. Water constantly moving, and herbicides begin dissipating upon application. Objectives often target invasives while enhancing comingled desired spp. Pre-emergent strategies almost never apply. Photo credits: Texas A&M Extension (aquaplant.tamu.edu) & OSU Extension (go.osu.edu/gledn). APMS (2014)

28 Growth Forms: Algae Treatments with copper products (mostly wholewater) are long-term default with few realistic alternatives (APMS 2014). Copper sometimes blended with endothall or diquat and adjuvants/ surfactants for resistant spp. Increasingly common use of sodium carbonate peroxyhydrate products. Photo credits: Texas A&M Extension (aquaplant.tamu.edu).

29 Aquatic Plant Management: The Outline Prevention of related problems Management: Mechanical/Harvest Pre-application Aquatic herbicide overview Grass Carp

30 Lynch, W. E. Jr Chemical control of aquatic plants in ponds: extension fact sheet A School of Environment and Natural Resources, Ohio State University Extension, Columbus, OH.

31 Aquatic herbicide chemical Name Absorption Selectivity Water-Use Restrictions Copper (copper sulfate and copper chelates) Contact Broad Minimal Sodium carbonate peroxyhydrate Contact Broad Minimal Diquat Contact Broad Moderate Flumioxazin* Contact Broad Moderate Carfentrazone-ethyl* Contact Broad Moderate Endothall (amine salt and potassium salt) Contact Broad Moderate Glyphosate Systemic Broad Minimal Imazamox Systemic Broad Moderate Penoxsulam* Systemic Broad Moderate Topramezone* Systemic Selective Moderate Fluridone Systemic Selective Moderate Bispyribac* Systemic Selective Extensive Imazapyr Systemic Selective Extensive Triclopyr Systemic Selective Extensive 2,4-D Systemic Selective Extensive For details, see OSU fact sheet Chemical Control of Aquatic Plants (Lynch 2009) excepting *.

32 Contact herbicides Copper sulfate and copper chelates (a vast many: e.g., Cutrine brands, etc.): mostly algae (some submersed). Sodium carbonate peroxyhydrate (e.g., GreenClean, Pak 27, Phycomycin, etc.): near-surface and shallow algae. Diquat (e.g., Reward, Weedtrine-D, Aquastrike [Endothall-dipotassium blend], etc.): submersed plants and some filamentous algae. Flumioxazin* (e.g., Clipper): misc. submersed and free-floating plants, especially duckweeds and watermeal. Carfentrazone-ethyl* (e.g., Stingray): misc. floating and emergent plants. Endothall (e.g., Aquathol, Hydrothol, Evac Biocide, Aquastrike [Diquat blend]): submersed plants and algae. Karmex*/Diuron*, etc.: Do not use! Not labeled for aquatic applications. For details, see OSU fact sheet Chemical Control of Aquatic Plants (Lynch 2009) excepting *.

33 Systemic herbicides Glyphosate (e.g., Rodeo, Aquamaster, AquaPro, Eraser AQ, etc.): emergent plants. Imazamox (e.g., Clearcast): very broad effectiveness, including several submersed invasives. Topramezone* (e.g., Oasis): Select submersed, floating, and emergent species including several grasses. Fluridone (e.g., Sonar, Avast, Whitecap, etc.): primarily submersed and freefloating plants. Penoxsulam* (e.g., Galleon): emergent and some floating weeds including on exposed pond sediments. Bispyribac* (e.g., Tradewind): misc., esp. floating and submersed. Imazapyr (e.g., Habitat, Arsenal, etc.): emergent (esp. grasses) & some floating weeds. 2,4-D (e.g., AquaKleen, Navigate, Aquacide, Sculpin G, Weedar 64, etc.): specific plant species such as Eurasian watermilfoil, coontail, and limited effectiveness on waterlilies. Triclopyr (e.g., Renovate, Vastlan, Garlon 3A, Navitrol, etc.): selective aquatic effectiveness similar to 2,4-D. For details, see OSU fact sheet Chemical Control of Aquatic Plants (Lynch 2009) excepting *.

34 Aquatic Plant Management: The Outline Prevention of related problems Management: Mechanical/Harvest Pre-application Aquatic herbicide overview Grass Carp

35 Grass Carp (or White Amur) An herbivore (a plant eater) native to Asia. Prefers many of our native, submerged plant species. Only sterile, triploid Grass Carp may be stocked in Indiana (or Ohio). Stocking rate varies depending upon severity of plant overgrowth (ordinarily, 2 10 per acre). Photo credit: Scott Heidrich (2011).

36 Grass Carp: Constraints Rarely control filamentous algae, duckweeds, Eurasian watermilfoil, or cattails. Tough to remove once stocked. In removing competition for nutrients by eating rooted plants, Grass Carp can actually contribute to filamentous algae or duckweed blooms in some situations, at least in short term. Dense stocking likely precludes beneficial uses of native aquatic plants. (Write for a fact sheet with table listing plant preferences.)

37 (Far north Lake Huron: photo credit, me!)

38 Aquatic Plant Management Eugene Braig, Program Director, Aquatic Ecosystems Pond Clinics, a smattering around the state of Ohio, Spring Summer 2017