Integrated Pest Management & Certification Training Aquatic Weed Management Richard D. Lee, Ph.D. IPM Specialist Bureau of Land Management

Aquatic Plants In natural systems such as lakes and ponds, light to moderate growths of aquatic plants serve useful purposes: Provide oxygen, food and cover for fish and other aquatic organisms, and may stabilize bottom sediment.

Aquatic Plants In overabundance, many species become “weedy” as they crowd out desirable plants, adversely affecting other aquatic life and our ability to use the water: Recreation Creation of foul odors and discoloration Fish kills Blockage of water flow

Aquatic Weeds My goal this morning is to provide you with the necessary background information to allow you to understand the procedure for developing an aquatic weed management plan.

Classification of Aquatic Weeds Two groups of aquatic plants: 1. Algae - simple plants without roots, leaves or stems. They reproduce by cell division, fragmentation, or by spore formation. 2. Vascular plants - plants having roots, stems, leaves, and flowers. There are four classes - submersed, free- floating, rooted floating, emerged plants.

Aquatic Weeds - Algae Three types: 1. Microscopic algae - single celled or colonial algae. Also referred to as “Phytoplankton” when suspended in water. During the daylight - give off oxygen, During night - remove oxygen. If overabundant - fish kill due to oxygen removal from water - referred to as an “algal bloom” - the result of too much fertilizer in pond.

Aquatic Weeds - Algae Three types: 1. Microscopic algae 2. Filamentous algae - thread-like filaments that form mats on surface of the pond. As algae photosynthesize, oxygen gets trapped in the body causing them to rise to the surface as clumps. Examples: - Spirogyra - bright green and slimy - Cladophora - cotton mat algae, due to texture - Pitophora - horsehair coarse

Aquatic Weeds - Algae Three types: 1. Microscopic 2. Filamentous 3. Chara - looks more like a plant with leaves needle-like and arranged in whorls along the “stem”. Musky odor and gritty surface due to calcium deposits. Also called “stonewort”

Submersed Plants

Aquatic Weeds - Vascular Plants – Submersed Plants Four Groups: 1. Submersed plants - rooted to the bottom and completely submersed except for flowers which may extend above the water. Often referred to as “moss”. Identification based upon: * Leaf arrangement * Leaf shape

Aquatic Weeds - Vascular Plants Submersed Plants - Alternate Leaves: One leaf per node PONDWEEDS - (Potamogeton sp.) Curly Leaf Pondweed Sago Pondweed Leafy Pondweed

Aquatic Weeds - Vascular Plants Submersed Plants - Opposite Leaves: Two leaves per node NAIADS (Najas sp.) Southern naiad Brittle naiad

Aquatic Weeds - Vascular Plants Submersed Plants - Whorled Leaves: Three or more leaves per node, arranged in a whorl. Most serious submersed aquatic plants fit in this group. Examples: COONTAIL - Ceratophyllum demersum AMERICAN ELODEA - Elodea canadensis EURASIAN WATERMILFOIL - Myriophyllum spicatum There are other watermilfoils, including parrotfeather. HYDRILLA - Hydrilla verticillata

Got to Know Your Weeds: Eurasian Watermilfoil Eurasian Watermilfoil Myriophyllum spicatum Submerged, rooted perennial. Grows in depths of up to 15 feet deep. Forms dense mats.

Got to Know Your Weeds: Parrotfeather Parrotfeather Myriophyllum aquaticum Submerged, rooted perennial. Forms dense mats. Whorled leaves.

Got to Know Your Weeds: Hydrilla Hydrilla Hydrilla verticillata Forms dense mats.

Aquatic Weeds - Vascular Plants – Free Floating Four Groups: 1. Submersed plants 2. Free-floating Plants - these plants live unattached to the soil. There are roots, extend only in the water for nutrient uptake. Majority of the plant is flattened or boat-shaped clusters of leaves with short segmented stems.

Free Floating

Aquatic Weeds - Vascular Plants Free-floating Plants: Examples: DUCKWEED - (Lemna sp.) - 0.5” across, with 2 to 4 leaves. WATERMEAL - (Spirodela sp.) - 1/16” diameter GIANT SALVINIA – (Salvinia molesta) WATER HYACINTH - (Eichhornia crassipes) - major aquatic weed of concern

Got to Know Your Weeds: Giant Salvinia Giant Salvinia Salvinia molesta Native to South America First found in U.S. in 1995 in South Carolina. Now found in 24 watersheds in Texas, California, Arizona, Louisiana, Mississippi, Alabama, Georgia, & Florida. Southern States most susceptible.

Got to Know Your Weeds: Giant Salvinia Giant Salvinia Salvinia molesta Forms dense mats.

Got to Know Your Weeds: Water Hyacinth Water Hyacinth Eichhornia crassipes

Aquatic Weeds - Vascular Plants – Rooted Floating Four Groups: 1. Submersed plants 2. Free-floating Plants 3.Rooted Floating Plants - also referred to as “Emersed Weeds” on some labels. Plants are rooted in the bottom sediments in shallow water. Leaves are floating or erect. Plants identification by leaf shape and petiole attachment.

Rooted Floating

Aquatic Weeds - Vascular Plants Rooted Floating Plants: Center Attachment of Petiole WATER LOTUS WATERSHIELD Cleft or Edge Petiole Attachment WATER LILY SPATTERDOCK

Aquatic Weeds - Vascular Plants – Emergent Plants Four Groups: 1. Submersed Plants 2. Free-floating Plants 3. Rooted Floating Plants 4. Emergent Plants - Most of the plant is above the water surface. Common Examples: Purple Loosestrife Salt Cedar

Emergent Plants

Got to Know Your Weeds: Purple Loosestrife

Remembering our four step approach to weed management will assist in developing a management plan for aquatic weeds: 1. Prevention 2. Early Detection 3. Timely Management 4. Site Rehabilitation Aquatic Weeds - Management

Prevention: We need to be aware of the potential threat aquatic weeds have for our areas and learn to recognize those weeds of concern. Giant Salvinia - is a problem in Texas and has the potential to make it into this area. Purple Loosestrife - a serious problem in the Eastern portion of the U.S. and moving our way.

Aquatic Weeds - Management The key here - is we need to be looking at what is growing in our ditches and lakes.

Aquatic Weeds - Management Early Detection: Timely Management: Biological Mechanical Cultural: Proper construction – steep slopes – keep water moving Draining/Drying – species dependent Use of Herbicides

Aquatic Weeds - Management Timely Management: Biological - the use of living organisms to manage other living organisms. Limited options available. Tilapia – plant eating fish White Amur – plant eating fish, concerns regarding its environmental impact. Mechanical - Cutting, Mowing, Raking, Digging

Aquatic Weeds - Management Herbicides Available: Algae – Copper sulfate Submersed – Diquat, Endothall, Fluridone, 2,4-D Free Floating – Diquat, Emersed – Glyphosate, Triclopyr

Aquatic Weeds - Management Use of Herbicides - before using a herbicide, make sure you have answers for the following questions: 1. What is the use of the treated water? 2. Characteristics of the Environment 3. Characteristics of the Water 4. Characteristics of the Selected Herbicide

Aquatic Weeds - Management Herbicides and Static Water: Floating and emerged weeds are easy to manage. Submerged weeds and algae not real difficult. Herbicides and Flowing Water: Floating and emerged weeds are still easy to manage. Submerged weeds and algae can only be managed effectively through continuous application at a particular point to maintain a specified level of herbicide concentration - it’s not easy.

Aquatic Weeds - Management Application of Aquatic Herbicides: 1. Application equipment - is it in good working order. 2. Determine area to be treated: Aquatic Situation Determining Treated Area AlgaeWater Volume - acre -ft Submersed PlantsWater Volume - acre-ft Free-FloatingSurface Area - acres Rooted Floating PlantsSurface Area - acres Emergent PlantsSurface Area - acres

Aquatic Weeds - Management Application of Aquatic Herbicides - Pond: Surface Area: Free-floating, rooted-floating, and emerged weeds Two dimensional - length X width Rate of herbicide application based upon “amount/acre”

Aquatic Weeds - Management Application of Aquatic Herbicides - Pond: Water Volume: Algae and submerged Three dimensional - length X width X depth Rate of herbicide application based upon “amount/acre-ft” or “ppm” (Parts per million). To convert “ppm” to “lbs. product required” 2.7 X PPM wanted X acre-ft = lbs. Prod. Req.

Aquatic Weeds - Management Application of Aquatic Herbicides - Canal/Moving: Herbicide application depends upon: Water Volume: Average width X Average depth = sq. ft. Flow Speed: Distance water moves per unit of time = ft/sec FLOW RATE: Water volume X Flow Speed = cubic feet/sec

Aquatic Weeds - Summary 1. Different Types of Weeds: Algae Submersed Weeds Free-floating Weeds Rooted Floating Weeds Emergent Weeds 2. Management Plan Development