Eurasian Watermilfoil

Myriophyllum spicatum

By: Briana Betress

•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

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

National Distribution

Statewide Distribution

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

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.

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

library.umf.maine.edu/plagiarism/credit2.html

Any Questions?

References• http://www.forestryimages.org/images/384x256/0002004.jpg

• http://plants.usda.gov/java/profile?symbol=MYSP2

• library.umf.maine.edu/plagiarism/credit2.html

• www.cnipm.org/images/Myriophyllum_spicatum.jpg

• http://nas.er.usgs.gov/taxgroup/plants/docs/my_spica.html

• http://www.hear.org/Pier/images/myspi12.jpg

• http://fwcb.cfans.umn.edu/research/milfoil/milfoilbc/bcresearch.html

• http://www.rcweeds.org/Weed_List/IMAG045.JPG