Floating Weed Control Brett W. Bultemeier & William T. Haller University of Florida, IFAS Center for Aquatic and Invasive Plants http://plants.ifas.ufl.edu
The Enemies Water Hyacinth (Eichhornia crassipes) Exotic Water Lettuce (Pistia stratiotes) Exotic?? Duckweed Some exotic Lemna sp.: Only ONE root Landoltia punctata: Multiple roots Frog s-bit (Limnobium spongia) Water meal (Wolffia columbiana) Giant Salvinia (Salvinia molesta) Exotic Mosquito fern (Azolla caroliniana)
Why control Hard to use boats Irrigation blockage Looks bad Mosquito control Rapid reproduction and large biomass Hyacinth 200-300 tons/acre Reproduce every 5-7 days From one plant about 4.5 months for one acre
Water Hyacinth
Water Hyacinth Eichhornia crassipes World s worst aquatic weed Native to Brazil Introduced 1884 in New Orleans Ornamental ~$2-5 million per year for control
Frog s-bit vs. Water Hyacinth
Hyacinth and Frog s-bit Control Water Hyacinth Frog s-bit 2,4-D Glyphostate Diquat Imazapyr Triclopyr Diquat Imazapyr
Water Lettuce
First described in 1765 Africa or native?? 100-1000 rosettes/m 2 Control options Diquat Endothall Glyphosate Imazapyr Carfentrazone Water Lettuce
Duckweed Both native and non-native Resistance becoming an issue Landoltia punctata Diquat resistant Copper can overcome resistance Control Fluridone Diquat Copper
Remaining bad guys
Keys for management Label, label, label Proper identification IFAS publications plants.ifas.ufl.edu Extension agents Proper calculations Area, speed, % solution Good coverage Surfactants, wetting agents Herbicide rotation Experience
Emergent Weed Control - Ditch and pond banks -
Problems Created by Weeds Reduce cross sectional area Cause blockage Impede flow Reduce drainage rates Ponds Aesthetics Access
Methods of Control Mechanical Mowing Annual plants Excavation Burning Chemical Very similar to terrestrial weed control Product must be labeled for aquatic use
Mowing Broadleaves vs. grasses Annuals vs. perennials Annuals Time mowing to inhibit seed formation
Mower
Chemical Control - First Step Proper weed ID Herbicide selection Target weeds vs. beneficial weeds Generally, broad leaf control and promote grasses Bare dirt = erosion problems
Determine All Water Uses Potable water Irrigation water Recreational use Livestock consumption Drainage water Where is the water going?
Herbicide Selection DITCHBANK WEED CONTROL Labeled for aquatic use Overspray, over water, etc. Some can be applied to dry ditches Ensure use-site is on the label Non-irrigation ditches, irrigation ditches, slow-flowing canals, flowing canals
Herbicide Selection Spectrum of activity Selective vs. non-selective Maintain grass cover Soil residual Contact vs. systemic
AVOID OVERSPRAY AND DRIFT Water on edge mixes rapidly Product will move rapidly into main flow
Application timing Established perennials bud to bloom stage Cattails apply glyphosate after flower production Pre-flower energy up for flower production After-flower energy down for storage Annual and biennials early growth stage
Calibration Most labels indicate pints or quarts per acre Use sufficient diluent to ensure even coverage 20 to 100 gpa Some labels indicate % spray solution
Surfactants Most labels will recommend a surfactant Non-aquatic glyphosate (Round-up) Surfactant is prohibited for use in water Aquatic glyphosate (Rodeo) MUST use a surfactant that is allowed in water Follow all label directions
Summary READ THE LABEL Cattails on shore ok to treat Cattails in the water may not be ok Know water use restrictions Mistakes cost big money (lawyers) Know where the water is going READ THE LABEL
Thank You Questions? plants.ifas.ufl.edu