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Hydrilla verticillata ( L.f .) Royle. Presented by Garrett Noles. Common Names + Synonyms. Common- Hydrilla , water thyme, Florida elodea
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Hydrillaverticillata (L.f.) Royle Presented by Garrett Noles
Common Names + Synonyms • Common- Hydrilla, water thyme, Florida elodea • Latin binomials- Hottoniaserrata, Hydrillaangustifolia, Hydrillaovalifolia, Leptanthesverticillata, Serpiculaverticillata, Elodea verticillata Photo by USDA/ARS www.cal-ipc.org
Taxonomy • Family- Hydrocharitaceae (Tape-grass family) • Reproduction- Mainly vegetative propagation • Dioecious (mostly in US) & rarely monoecious • Morphology- Stems: long and slender, white in color • Leaves- dark green, strap shaped, saw-toothed margins • Grow in dense clusters, branching towards surface of water www.cal-ipc.org
Turions • Turions- “dark green buds on some leaf axils” • Subterranean turions- yellow tuber like buds attached to root folicles plants.ifas.ufl.edu
Current distribution of Hydrillaverticillata USDA Plants 2010
Ecological Impacts • Can outcompete other desirable aquatic plants • Can slow water flow thus increase water temperature • Can use the oxygen resources in a water body • Some evidence of allelopathy discouraging plant biodiversity (if interested view starred paper) • Can alter important freshwater fish habitat
Economic Impacts • Can reduce water recreation • Turions and fragments can clog irrigation canals • Can reduce hydropower productivity • Mechanical and chemical treatments can add up over a period of time to be costly
Biological Control • Hydrilla leaf-mining fly and hydrilla tuber weevil • Both found in India mid 80’s • Are major species specific predators for Hydrilla plants.ifas.ufl.edu
Insect Herbivory Effects • 14,000 L tanks • Each divided into 32 sections • Competition tests and herbivory tests in different tanks • Concluded that combo of bio controls are most effective Doyle et.al. 2007
Bio Control Cont. • Another biological enemy to hydrilla from Asia • Grow fast, and consume tubers/turions! • However, grass carp are not species specific foragers Ctenopharyngodonidella (Grass Carp) www.ecy.wa.gov
Effectiveness of Grass Carp • Consume large amounts until they reach maximum size • Smaller fish consume more vegetation • Once size limit is reached, no longer a great control agent Osborne 1981
Chemical Controls • Endothall (Aquathol K) • Can be used selectively • Kills vegetation, not tubers • Diquat (Reward) • Is effected by water solids(silt) • Usually used for one season • Reward prices vary, check local provider ($130-150/gallon) • Aquathol powder form prices also vary ( $240-260/10 lbs) • Aquathol liquid form ($240-260/ 2.5 gallons) www.ecy.wa.gov
Work Cited • California Invasive Plant Council (2010)Cal-IPC Resources on Hydrillaverticillata. http://www.cal-ipc.org/ip/management/plant_profiles/Hydrilla_verticillata.php, April 18, 2010. • Doyle R, Grodowitz M, Smart M, Owens C (2007) Separate and interactive effects of competition and herbivory on the growth, expansion, and tuber formation of Hydrillaverticillata. Biological Control 41: 327-338. • Kulshreshtha M, Gopal B (1983) Allelopathic influence of Hydrillaverticillata on the distribution of Ceratophyllum species. Aquatic Botany 16: 207-209. * • Osborne JA, Sassic NM (1981) The size of grass carp as a factor in the control of Hydrilla. Aquatic Botany 11: 129-136. • University of Florida IFAS (2009) Center for Aquatic and Invasive Plants.http://plants.ifas.ufl.edu/node/183, April 17, 2010 • USDA, ARS. 2010. The Agriculture Research Service Database (http://www.ars.usda.gov, 21 April 2010). ARS Headquarters, Washington DC, 20250.
Work Cited Cont. • USDA, NRCS. 2010. The PLANTS Database (http://plants.usda.gov, 21 April 2010). National Plant Data Center, Baton Rouge, LA 70874-4490 USA. • Washington State Department of Ecology (2010) Aquatic Plant Management- Aquatic Herbicides. http://www.ecy.wa.gov/programs/wq/plants/management/aqua028.html, April 16, 2010. • Washington State Department of Ecology (2010) Aquatic Plant Management- Triploid Grass Carp. http://www.ecy.wa.gov/programs/wq/plants/management/aqua024.html, April 17, 2010.