Eurasian Watermilfoil

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Eurasian Watermilfoil Myriophyllum
spicatum By Briana Betress
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• Native to Europe, Asia, and North Africa
• First documented in 1942, confirmed in 45 states
• Introduced by Aquarium trade
• Spread mainly by boating activity as well as
  naturally
• Habitat Lakes, Ponds, Shallow Reservoirs, Low
  flow river and stream areas, brackish waters of
  protected tidal creeks and bays.
• Especially abundant in areas of nutrient loading,
  intense plant management, or boat use.
• Submersed, rooted, perennial herb
• Whorled, finely divided leaves with leaflets in
  pairs of 14

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Why Eurasian Watermilfoil is Problematic

• Ability to reproduce in fragments
• High growth rate in a range of temperatures
• Tolerant of a range of environmental conditions

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National Distribution
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Statewide Distribution
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Control Methods

• Mechanical
• Several cuts may be needed- like mowing your lawn
• Dredging and rotavation can eliminate all plants
• Mechanical harvesters are effective but costly
• Chemical
• May need to be repeated every 1-4 years
• 2-4-D , used for dicots
• Bio
• Three taxa considered for use on Myriophyllum
  spicatum
• Acentria ephemerella
• Cricotopus myriophylli
• Euhrychiopsis lecontei

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Biocontrols

• Pyralid Moth-
• Acentria ephemerella
• Consumes meristem, stem, and leaves.
• Unsure of host specificity

• Hydrilla tip mining midge-
• Cricotopus myriophylli
• Consumes meristem
• Problems with mass rearing, and funding has
  slowed research

• Milfoil Weevil-
• Euhrychiopsis lecontei
• Bores through stem, reducing buoyancy and
  carbohydrate storage capacity.

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Biocontrol- Milfoil Weevil

• Euhrychiopsis lecontei
• 3mm in length
• Completes all life stages submersed

• Larvae are stem miners
• Insectivorous fish may be decreasing weevil
  populations

Egg Larva Pupa
Adult
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Any Questions?
library.umf.maine.edu/plagiarism/credit2.html
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References

• http//www.forestryimages.org/images/384x256/00020
  04.jpg
• http//plants.usda.gov/java/profile?symbolMYSP2
• library.umf.maine.edu/plagiarism/credit2.html
• www.cnipm.org/images/Myriophyllum_spicatum.jpg
• http//nas.er.usgs.gov/taxgroup/plants/docs/my_spi
  ca.html
• http//www.hear.org/Pier/images/myspi12.jpg
• http//fwcb.cfans.umn.edu/research/milfoil/milfoil
  bc/bcresearch.html
• http//www.rcweeds.org/Weed_List/IMAG045.JPG