Eurasian water milfoil

Alert

Have you seen Eurasian water milfoil?

Be on the lookout for Eurasian water milfoil and report it to Biosecurity Queensland. Early detection and reporting are the key elements in controlling Eurasian water milfoil.

Call us on 13 25 23.

Native to Eurasia and northern Africa, Eurasian water milfoil is a submerged aquatic plant that can grow quickly and invade waterways. It has not been found in Queensland so far but could become a major pest here if introduced.

Biosecurity Queensland encourages people to report this Class 1 pest plant and take action to help stop the establishment, to prevent the spread, and to control this pest.

Eurasian water milfoil is a prohibited invasive plant under the Biosecurity Act 2014.

Scientific name

Myriophyllum spicatum

Similar species

  • Native myriophyllum ssp., ceratophyllum demersum

Description

  • Submersed aquatic plant.
  • Emergent flower heads are orange to red.
  • Leaves are dissected, 'feathery', in whorls of 4, contain 12 to 21 leaflets.
  • Long stems form surface-reaching mats.
  • Plant forms turions (dormant, detached buds) for overwintering.
  • Rhizomes root to 10m depth, can grow 3-5m to surface.

Habitat

  • Prefers slow-flowing and standing water bodies.
  • Can grow in fresh and saline water.
  • Grows well in nutrient-rich water.

Distribution

  • Not found in Queensland but has the potential, if introduced, to become a pest in most parts of Queensland.

Life cycle

  • Begins growth in spring with increasing water temperature, achieves maximum growth in water above 18°C.
  • Flowers in summer once stems reach water surface, pollinated by wind and insects.
  • Plants fragment after flowering and die back to rhizomes towards winter; rhizomes resprout in spring.

Impacts

Environmental

  • Grows quickly in calm water bodies such as reservoirs and dams, eventually blocking waterway.
  • Displaces native aquatic plants and reduces biodiversity.
  • Dense infestations can affect water quality.
  • Creates favourable mosquito habitat.

Social

  • Impedes recreational activities such as waterskiing and fishing.
  • Interferes with infrastructure such as irrigation.
  • Poses danger for swimmers, who can become entangled.

How it is spread

  • Propagates through seeds and stem fragments.
  • Seeds can be spread by waterbirds.
  • Fragments are spread by water currents and humans and are main way plant spreads.

Control

Herbicide control

  • Controlled with herbicides overseas (2,4D, Diquat, endothall, copper, fluridone).

Biological control

  • No known biological control agents.

Legal requirements

  • Eurasian water milfoil is a prohibited invasive plant under the Biosecurity Act 2014.
  • It must not be given away, sold, or released into the environment without a permit.
  • The Act requires that all sightings to be reported to Biosecurity Queensland within 24 hours.
  • By law, everyone has a general biosecurity obligation (GBO) to take all reasonable and practical steps to minimise the risk of Eurasian water milfoil spreading until they receive advice from an authorised officer.

Further information