Aquatic Plant Management

Transcription

1 Aquatic Plant 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. (Write to request.)

4 Some Pond Management References Herbicide specific University of Arkansas Division of Agriculture, Research and Extension Recommended chemicals for weed and brush control, MP44. Cooperative Extension Service, University of Arkansas System, Little Rock, AR. Vast, comprehensive, and requires a bit of savvy to digest.

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

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

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

8 Prevention: Nutrient management Recognize and manage potential sources of excessive nutrients. From the watershed: Fertilize conservatively. Maintain septic systems. Discourage Canada Geese. Tolerate terrestrial and wetland vegetation. Within the pond: Aerate! Tolerate some aquatic vegetation. Use chemical coagulants (e.g., aluminum sulfate) as necessary. Do you think this pond has a large goose population (Eugene Braig 2015)?

9 Aquatic plant tolerance (Eugene Braig 2016) Tolerate 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).

10 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.

11 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.

12 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 to sustain function through growing season. Use dyes as necessary to limit productivity in deep water. Most effective: As preventative measure (apply early in the season, before any substantial growth). To sites with long retention times of water. To sites with adequate depth and slope. Spot treat with chemical herbicides as necessary to maintain stands of vegetation at desired coverage.

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

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

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

16 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. Often when water temperature reaches 60 o F. Estimate volume: surface area (acres) x depth (feet) = volume in acre-feet. Follow label recommendations for application rate by volume treated.

17 Pre-application considerations: Amount of area/volume treated Spot Treatment: Good for leaving desirable stands of vegetation. Recommended exclusively once water temperatures exceed 72 F or so. Granular formulae preferred: easier to apply 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 risk of oxygen crash and fish kill. Warm water less able to hold oxygen. Loss of vegetation deprives the pond of its major oxygen source. Decomposition of dead plant material consumes oxygen. Can run out of oxygen in the early morning hours.

18 Pre-application considerations: two basic considerations Treat as early and conservatively as possible once: 1. Target plant is present (has begun season s growth), and 2. Water has reached effective temperature for chosen product (see label).

19 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.)

20 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)

21 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)

22 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).

23 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)

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

25 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-acting. 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.

26 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. (Write to request.)

27 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 Florpyrauxifen-benzyl* 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 *.

28 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, Pond-Klear): misc. submersed and freefloating 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 *.

29 Systemic herbicides Glyphosate (e.g., Rodeo, Aquamaster, AquaPro, Eraser AQ, etc.): emergent plants. Imazamox (e.g., Clearcast): very broad effectiveness, including several submersed invasives. Penoxsulam* (e.g., Galleon): emergent and some floating weeds including on exposed pond sediments. 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. Florpyrauxifen-benzyl* (e.g., ProcellaCOR EC): Select free-floating, emergent, and submersed species, especially watermilfoils and several invasives. 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 *.

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

31 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 Ohio. Stocking rate varies depending upon severity of plant overgrowth (ordinarily, 2 10 per acre). Photo credit: Scott Heidrich (2011).

32 Grass Carp limitations 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 make filamentous algae problems worse 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.)

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

34 Aquatic Plant Management Ohio pond clinics, 2019 Eugene Braig, Program Director, Aquatic Ecosystems