Invasive Species Compendium

Detailed coverage of invasive species threatening livelihoods and the environment worldwide

Datasheet

Ageratina riparia
(mistflower)

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Datasheet

Ageratina riparia (mistflower)

Summary

  • Last modified
  • 22 November 2019
  • Datasheet Type(s)
  • Invasive Species
  • Preferred Scientific Name
  • Ageratina riparia
  • Preferred Common Name
  • mistflower
  • Taxonomic Tree
  • Domain: Eukaryota
  •   Kingdom: Plantae
  •     Phylum: Spermatophyta
  •       Subphylum: Angiospermae
  •         Class: Dicotyledonae
  • Summary of Invasiveness
  • Ageratina riparia is unpalatable to livestock and is toxic. It reduces the carrying capacity of pastures and rangeland and restricts movement of machinery and stock. The weed has potential for rapid natural spread throughout its potential...

  • Principal Source
  • US Federal Noxious Weed List (draft fact sheet 2011)

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    Compendia
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    UK
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Identity

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Preferred Scientific Name

  • Ageratina riparia (Regel) R. M. King & H. Rob.

Preferred Common Name

  • mistflower

Other Scientific Names

  • Eupatorium riparium Regel

International Common Names

  • English: creeping croftonweed; river-eupatorium; spreading snakeroot

Local Common Names

  • South Africa: mistblom
  • USA/Hawaii: hamakua pamakani

Summary of Invasiveness

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Ageratina riparia is unpalatable to livestock and is toxic. It reduces the carrying capacity of pastures and rangeland and restricts movement of machinery and stock. The weed has potential for rapid natural spread throughout its potential range (e.g., high reproductive potential and highly mobile propagules). A. riparia is a prolific seeder and grows very fast, becoming the dominant vegetation in an invaded area (Barreto and Evans, 1988). Leachates from leaves and plant litter have an allelopathic effect on other plants. A. riparia is among the primary threats to 25 endangered species on the island of Oahu in Hawaii. The potential negative impacts outweigh any limited value the species has as an ornamental.

A. riparia was added to the US Federal Noxious Weed List and seed list in 2010. Hawaii lists A. riparia as a noxious weed for eradication and control purposes.

Taxonomic Tree

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  • Domain: Eukaryota
  •     Kingdom: Plantae
  •         Phylum: Spermatophyta
  •             Subphylum: Angiospermae
  •                 Class: Dicotyledonae
  •                     Order: Asterales
  •                         Family: Asteraceae
  •                             Genus: Ageratina
  •                                 Species: Ageratina riparia

Description

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A. riparia can be an erect or sprawling herb to small shrub. Stems are cylindrical and have a purplish tint. Its green, opposite leaves can grow up to 15 centimeters long and 4 centimeters wide and range from lanceolate to narrow ovate. Leaves also display toothed margins. Flowers are arranged in flat-topped showy white clusters that produce 5-angled seeds 1-2 millimeters long and topped with 3-4 millimeter long bristles.

Plant Type

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Herbaceous
Shrub

Distribution

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A. riparia is a serious pest in Africa, India, Indonesia, Papua New Guinea, Southeast Asia, Australia, New Zealand, Jamaica, Madagascar, and Hawaii. It was introduced to the USA as an ornamental and by agricultural contamination. It is likely to establish populations in the warm southeast USA, particularly in Florida and Texas. Its preferred habitats include misty upland pastures and mountainous areas with high levels of precipitation.

Distribution Table

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The distribution in this summary table is based on all the information available. When several references are cited, they may give conflicting information on the status. Further details may be available for individual references in the Distribution Table Details section which can be selected by going to Generate Report.

Last updated: 25 Feb 2021
Continent/Country/Region Distribution Last Reported Origin First Reported Invasive Reference Notes

Africa

MadagascarPresentIntroduced
MauritiusPresentIntroduced
RéunionPresentIntroduced

Asia

IndonesiaPresent

Europe

SpainPresentPresent based on regional distribution.
-Canary IslandsPresentIntroduced

North America

CubaPresentIntroduced
JamaicaPresentIntroduced
MexicoPresentIntroduced
United StatesPresentPresent based on regional distribution.
-HawaiiPresentIntroducedInvasive

Oceania

AustraliaPresentIntroduced
New ZealandPresentIntroduced

South America

PeruPresentIntroduced

Habitat List

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CategorySub-CategoryHabitatPresenceStatus
Terrestrial
Terrestrial ManagedManaged grasslands (grazing systems) Principal habitat
Terrestrial Natural / Semi-naturalNatural grasslands Principal habitat

Biology and Ecology

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A. riparia is a prolific seeder and grows very fast, becoming the dominant vegetation in an invaded area (Barreto & Evans, 1988). In Australia, mature plants produce between 10,000 and 100,000 seeds annually. The seed can germinate immediately when in light (Parsons and Cuthbertson, 1992). Seeds are dispersed by wind and water. Colonies increase in density and size by horizontal spread and rooting at nodes.

Natural enemies

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Natural enemyTypeLife stagesSpecificityReferencesBiological control inBiological control on
Entyloma ageratinae Pathogen Hawaii

Pathway Causes

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CauseNotesLong DistanceLocalReferences
Hitchhiker Yes
Ornamental purposes Yes

Pathway Vectors

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VectorNotesLong DistanceLocalReferences
Plants or parts of plants Yes

Plant Trade

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Plant parts liable to carry the pest in trade/transportPest stagesBorne internallyBorne externallyVisibility of pest or symptoms
True seeds (inc. grain) seeds Yes

Impact Summary

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CategoryImpact
Biodiversity (generally) Negative
Economic/livelihood Negative

Threatened Species

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Threatened SpeciesConservation StatusWhere ThreatenedMechanismReferencesNotes
Bidens campylotheca subsp. pentamera (ko`oko`olau)CR (IUCN red list: Critically endangered); USA ESA listing as threatened speciesHawaiiCompetition (unspecified)US Fish and Wildlife Service (2013)
Cyanea recta (Kealia cyanea)National list(s); USA ESA listing as threatened speciesHawaiiCompetition - monopolizing resourcesUS Fish and Wildlife Service (1995)
Cyrtandra limahuliensis (Limahuli cyrtandra)NatureServe; USA ESA listing as threatened speciesHawaiiCompetition - monopolizing resourcesUS Fish and Wildlife Service (1995)
Isodendrion longifolium (longleaf isodendrion)EN (IUCN red list: Endangered); USA ESA listing as threatened speciesHawaiiCompetition - monopolizing resourcesUS Fish and Wildlife Service (2011b)
Lobelia monostachya (Waianae Range lobelia)CR (IUCN red list: Critically endangered); USA ESA listing as endangered speciesHawaiiCompetition (unspecified)US Fish and Wildlife Service (1998)
Lobelia niihauensis (Niihau lobelia)NatureServe; USA ESA listing as endangered speciesHawaiiCompetition - stranglingUS Fish and Wildlife Service (1998)
Lysimachia filifolia (Wailua River yellow loosestrife)USA ESA listing as endangered speciesHawaiiCompetition - smotheringUS Fish and Wildlife Service (1995)
Nototrichium humile (kaala rockwort)EN (IUCN red list: Endangered); USA ESA listing as endangered speciesHawaiiCompetition - monopolizing resourcesUS Fish and Wildlife Service (2008b)
Peucedanum sandwicense (makou)NatureServe; USA ESA listing as threatened speciesHawaiiCompetition (unspecified)US Fish and Wildlife Service (2011a)
Poa mannii (Mann's bluegrass)CR (IUCN red list: Critically endangered); USA ESA listing as endangered speciesHawaiiCompetition - monopolizing resourcesUS Fish and Wildlife Service (2010a)
Remya mauiensis (Maui remya)USA ESA listing as endangered speciesHawaiiCompetition (unspecified)US Fish and Wildlife Service (2009b)
Schiedea hookeri (sprawling schiedea)CR (IUCN red list: Critically endangered); USA ESA listing as endangered speciesHawaiiCompetition - monopolizing resources; Ecosystem change / habitat alterationUS Fish and Wildlife Service (2011c)
Schiedea kauaiensis (Kauai schiedea)CR (IUCN red list: Critically endangered); USA ESA listing as endangered speciesHawaiiCompetition - monopolizing resourcesUS Fish and Wildlife Service (2008a)
Pteris lidgatei (Lidgate's brake)CR (IUCN red list: Critically endangered); USA ESA listing as endangered speciesHawaiiCompetition - monopolizing resourcesUS Fish and Wildlife Service (2009a)
Silene lanceolata (Kauai catchfly)USA ESA listing as endangered speciesHawaiiCompetition - monopolizing resourcesUS Fish and Wildlife Service (2010b)
Spermolepis hawaiiensis (Hawaii scaleseed)USA ESA listing as endangered speciesHawaiiCompetition - monopolizing resourcesUS Fish and Wildlife Service (2010c)
Stenogyne kanehoana (Oahu stenogyne)CR (IUCN red list: Critically endangered); USA ESA listing as endangered speciesHawaiiCompetition (unspecified)US Fish and Wildlife Service (1998)
Tetramolopium filiforme (ridgetop tetramolopium)USA ESA listing as endangered speciesHawaiiCompetition (unspecified)US Fish and Wildlife Service (2010d)
Urera kaalaeCR (IUCN red list: Critically endangered); USA ESA listing as endangered speciesHawaiiCompetition - monopolizing resources; Ecosystem change / habitat alterationUS Fish and Wildlife Service (2011d)

Risk and Impact Factors

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Invasiveness
  • Proved invasive outside its native range
  • Highly mobile locally
  • Has high reproductive potential
Impact outcomes
  • Negatively impacts agriculture
  • Negatively impacts animal health
  • Negatively impacts livelihoods
  • Reduced native biodiversity
  • Threat to/ loss of endangered species
Impact mechanisms
  • Allelopathic
  • Competition - monopolizing resources
  • Competition - smothering
  • Competition - strangling
  • Competition (unspecified)

Uses List

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Environmental

  • Erosion control or dune stabilization
  • Ornamental

Materials

  • Poisonous to mammals

Prevention and Control

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Due to the variable regulations around (de)registration of pesticides, your national list of registered pesticides or relevant authority should be consulted to determine which products are legally allowed for use in your country when considering chemical control. Pesticides should always be used in a lawful manner, consistent with the product's label.

A pest risk assessment completed by APHIS, USA (Lehtonen, 2001) ranked A. riparia as medium in consequences of introduction and high in likelihood of introduction, resulting in an overall ranking of medium/high risk potential and the species was added to the US Federal Noxious Weed List and seed list in 2010. Hawaii lists A. riparia as a noxious weed for eradication and control purposes, which authorizes the State department of Agriculture to conduct control activities for this weed as time and resources permit.

A. riparia is resistant to many herbicides, but can be controlled if treated repeatedly (Parsons and Cuthbertson, 1992). The most effective method of biological control of this weed was the introduction of the fungus, Entyloma ageratinae, to infested areas in the state of Hawaii.

Bibliography

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Barreto, Robert W. and Evans, Harry C. 1988. Taxonomy of a Fungus Introduced into Hawaii for Biological Control of Ageratina riparia (Eupatorieae; Compositae), with Observations on Related Weed Pathogens. Transactions of the British Mycological Society 91: 81-97.

Lehtonen, Polly. 2001. Weed Risk Assessment for Ageratina riparia (Regel) R. M. King and H. Robinson (Mistflower) Version 6 Revised February 22, 2009 by Shirley Wager-Pagé Addendum to a report, Analysis and Assessment of the Invasive risk of Ageratina riparia, submitted by Sarah Reichard and Lizbeth Seebacher, University of Washington, College of Forest Resources, Center for Urban Horticulture. http://www.aphis.usda.gov/plant_health/plant_pest_info/weeds/riskassessments.shtml

Parsons, W. T. & E. G. Cuthbertson. 1992. Noxious weeds of Australia. Inkata Press, Melbourne, Sydney.

Thorp, J.R., Wilson, M (1998 onwards) Weeds Australia - http://www.weeds.org.au/

USDA, NRCS. 2009. The PLANTS Database (http://plants.usda.gov, 15 June 2009). National Plant Data Center, Baton Rouge, LA 70874-4490 USA.

References

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US Fish and Wildlife Service, 1995. Recovery Plan for the Kauai Plant Cluster. In: Recovery Plan for the Kauai Plant Cluster : US Fish and Wildlife Service.270 pp.

US Fish and Wildlife Service, 1998. Recovery Plan for Oahu Plants. In: Recovery Plan for Oahu Plants : US Fish and Wildlife Service.207 pp. + appendices.

US Fish and Wildlife Service, 2008. 5-Year Review, Short Form Summary: Species Reviewed: Schiedea kauaiensis (no common name). In: 5-Year Review, Short Form Summary: Species Reviewed: Schiedea kauaiensis (no common name) : US Fish and Wildlife Service.6 pp.

US Fish and Wildlife Service, 2008. Kulu`i (Nototrichium humile). 5-Year Review. In: Kulu`i (Nototrichium humile). 5-Year Review : US Fish and Wildlife Service.11 pp.

US Fish and Wildlife Service, 2009. 5-Year Review, Short Form Summary: Species Reviewed: Pteris lidgatei (no common name). In: 5-Year Review, Short Form Summary: Species Reviewed: Pteris lidgatei (no common name) : US Fish and Wildlife Service.7 pp.

US Fish and Wildlife Service, 2009. Remya mauiensis (Maui remya). 5-Year Review: Summary and Evaluation. In: Remya mauiensis (Maui remya). 5-Year Review: Summary and Evaluation : US Fish and Wildlife Service.15 pp.

US Fish and Wildlife Service, 2010. 5-Year Review, Short Form Summary: Species Reviewed: Poa mannii (Mann's bluegrass). In: 5-Year Review, Short Form Summary: Species Reviewed: Poa mannii (Mann's bluegrass) : US Fish and Wildlife Service.10 pp.

US Fish and Wildlife Service, 2010. Silene lanceolata (no common name). 5-Year Review: Summary and Evaluation. In: Silene lanceolata (no common name). 5-Year Review: Summary and Evaluation : US Fish and Wildlife Service.15 pp.

US Fish and Wildlife Service, 2010. Spermolepis hawaiiensis (no common name). 5-Year Review: Summary and Evaluation. In: Spermolepis hawaiiensis (no common name). 5-Year Review: Summary and Evaluation : US Fish and Wildlife Service.19 pp.

US Fish and Wildlife Service, 2010. Tetramolopium filiforme (no common name). 5-Year Review: Summary and Evaluation. In: Tetramolopium filiforme (no common name). 5-Year Review: Summary and Evaluation : US Fish and Wildlife Service.11 pp.

US Fish and Wildlife Service, 2011. Endangered and Threatened Wildlife and Plants; Listing 23 Species on Oahu as Endangered and Designating Critical Habitat for 124 Species. In: Endangered and Threatened Wildlife and Plants; Listing 23 Species on Oahu as Endangered and Designating Critical Habitat for 124 Species , 76(148) : US Fish and Wildlife Service.46362-46593. http://www.gpo.gov/fdsys/pkg/FR-2011-08-02/pdf/2011-17162.pdf

US Fish and Wildlife Service, 2011. Isodendrion longifolium (aupaka). 5-Year Review: Summary and Evaluation. In: Isodendrion longifolium (aupaka). 5-Year Review: Summary and Evaluation : US Fish and Wildlife Service.28 pp. http://ecos.fws.gov/docs/five_year_review/doc3809.pdf

US Fish and Wildlife Service, 2011. Schiedea hookeri (no common name). 5-Year Review: Summary and Evaluation. In: Schiedea hookeri (no common name). 5-Year Review: Summary and Evaluation : US Fish and Wildlife Service.20 pp.

US Fish and Wildlife Service, 2011. Urera kaalae (opuhe). 5-Year Review: Summary and Evaluation. In: Urera kaalae (opuhe). 5-Year Review: Summary and Evaluation : US Fish and Wildlife Service.19 pp.

US Fish and Wildlife Service, 2013. Endangered and Threatened Wildlife and Plants; Determination of Endangered Status for 38 Species on Molokai, Lanai, and Maui; Final Rule. In: Endangered and Threatened Wildlife and Plants; Determination of Endangered Status for 38 Species on Molokai, Lanai, and Maui; Final Rule , 78(102) : US Fish and Wildlife Service.32014-32065. https://www.gpo.gov/fdsys/pkg/FR-2013-05-28/pdf/2013-12105.pdf

USDA-ARS, 2011. Germplasm Resources Information Network (GRIN). Online Database. Beltsville, Maryland, USA: National Germplasm Resources Laboratory. https://npgsweb.ars-grin.gov/gringlobal/taxon/taxonomysearch.aspx

USDA-NRCS, 2011. The PLANTS Database. Baton Rouge, USA: National Plant Data Center. http://plants.usda.gov/

Distribution References

CABI, Undated. CABI Compendium: Status inferred from regional distribution. Wallingford, UK: CABI

USDA-ARS, 2011. Germplasm Resources Information Network (GRIN). Online Database. In: Germplasm Resources Information Network (GRIN). Online Database, Beltsville, USA: National Germplasm Resources Laboratory. http://www.ars-grin.gov/cgi-bin/npgs/html/tax_search.pl

USDA-NRCS, 2011. The PLANTS Database. In: The PLANTS Database, Baton Rouge, USA: National Plant Data Center. http://plants.usda.gov/

Wibowo T, Iskandar E A P, 2013. Broadleaved weeds in turf grass blocks of Cibodas Botanic Garden, Cianjur, Indonesia [Conference poster]. In: The role of weed science in supporting food security by 2020. Proceedings of the 24th Asian-Pacific Weed Science Society Conference, Bandung, Indonesia, October 22-25, 2013 [The role of weed science in supporting food security by 2020. Proceedings of the 24th Asian-Pacific Weed Science Society Conference, Bandung, Indonesia, October 22-25, 2013.], [ed. by Bakar B H, Kurniadie D, Tjitrosoedirdjo S]. Bandung, Indonesia: Weed Science Society of Indonesia. 578-582.

Principal Source

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US Federal Noxious Weed List (draft fact sheet 2011)

Distribution Maps

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