Invasive Species Compendium

Detailed coverage of invasive species threatening livelihoods and the environment worldwide

Datasheet

Ambrosia trifida
(giant ragweed)

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Datasheet

Ambrosia trifida (giant ragweed)

Summary

  • Last modified
  • 06 November 2018
  • Datasheet Type(s)
  • Invasive Species
  • Pest
  • Host Plant
  • Preferred Scientific Name
  • Ambrosia trifida
  • Preferred Common Name
  • giant ragweed
  • Taxonomic Tree
  • Domain: Eukaryota
  •   Kingdom: Plantae
  •     Phylum: Spermatophyta
  •       Subphylum: Angiospermae
  •         Class: Dicotyledonae
  • Summary of Invasiveness
  • A. trifida is an annual herb native to temperate North America which is now present in a number of countries in Europe and Asia. The primary means of spread of A. trifida occurs accidentally as a conta...

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Pictures

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PictureTitleCaptionCopyright
Leaf of A. trifida (giant ragweed). Leaves can posess between three and five lobes.
TitleLeaf
CaptionLeaf of A. trifida (giant ragweed). Leaves can posess between three and five lobes.
CopyrightPlant Resources Center/The University of Texas at Austin
Leaf of A. trifida (giant ragweed). Leaves can posess between three and five lobes.
LeafLeaf of A. trifida (giant ragweed). Leaves can posess between three and five lobes.Plant Resources Center/The University of Texas at Austin
Male flowers pike with exserted (protruding) anthers and female flowers just visible above the uppermost leaves. Ragweeds are a major contributing factor to autumn hayfever.
TitleFlowers
CaptionMale flowers pike with exserted (protruding) anthers and female flowers just visible above the uppermost leaves. Ragweeds are a major contributing factor to autumn hayfever.
CopyrightPlant Resources Center/The University of Texas at Austin
Male flowers pike with exserted (protruding) anthers and female flowers just visible above the uppermost leaves. Ragweeds are a major contributing factor to autumn hayfever.
FlowersMale flowers pike with exserted (protruding) anthers and female flowers just visible above the uppermost leaves. Ragweeds are a major contributing factor to autumn hayfever.Plant Resources Center/The University of Texas at Austin
Mature fruits in autumn, still surrounded by bracts. Note that the male heads have fallen from the rachis.
TitleFruits
CaptionMature fruits in autumn, still surrounded by bracts. Note that the male heads have fallen from the rachis.
CopyrightPlant Resources Center/The University of Texas at Austin
Mature fruits in autumn, still surrounded by bracts. Note that the male heads have fallen from the rachis.
FruitsMature fruits in autumn, still surrounded by bracts. Note that the male heads have fallen from the rachis.Plant Resources Center/The University of Texas at Austin

Identity

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Preferred Scientific Name

  • Ambrosia trifida L.

Preferred Common Name

  • giant ragweed

Other Scientific Names

  • Ambrosia aptera DC.
  • Ambrosia integrifolia Muhl. ex Willd.
  • Ambrosia trifida f. integrifolia (Muhl. ex Willd.) Fernald
  • Ambrosia trifida f. trifida
  • Ambrosia trifida subsp. trifida
  • Ambrosia trifida var. aptera (DC.) Kuntze
  • Ambrosia trifida var. heterophylla Kuntze
  • Ambrosia trifida var. integrifolia (Muhl. ex Willd.) Torr. & A.Gray
  • Ambrosia trifida var. polyploidea J.Rousseau
  • Ambrosia trifida var. texana Scheele
  • Ambrosia trifida var. trifida

International Common Names

  • English: blood ragweed; buffalo-weed; crownweed; great ragweed; horseweed
  • Spanish: Artemisa grande
  • French: ambroisie trifide; grande herbe à poux
  • Chinese: san lie ye tun cao

Local Common Names

  • Czech Republic: ambrozie trojklaná
  • Estonia: kolmehõlmane ambroosia
  • Finland: sormituoksukki
  • Germany: Dreilappentraubenkraut; Dreilappige Ambrosie; Dreilappiges Traubenkraut; Dreispaltige Ambrosie
  • Japan: kuwamodoki; oobutakusa
  • Latvia: trisdaivu ambrozija
  • Lithuania: triskiaute ambrozija
  • Netherlands: driedeelige Ambrosia
  • Norway: hesteambrosia
  • Poland: ambrozja trójdzielna
  • Slovakia: ambrózia trojzárezová
  • Slovenia: trikrpata žvrklja
  • Sweden: hästambrosia; tall Ambrosia
  • USA: bitterweed; buffalo weed; horse-cane; horse-weed; kinghead; tall ragweed

EPPO code

  • AMBTR (Ambrosia trifida)

Summary of Invasiveness

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A. trifida is an annual herb native to temperate North America which is now present in a number of countries in Europe and Asia. The primary means of spread of A. trifida occurs accidentally as a contaminant of seed or agricultural equipment. This species readily colonises disturbed areas and is often one of the first plants to emerge in early spring. As a result it has an initial competitive advantage and can therefore behave as a dominant species throughout the entire growing season. A. trifida is a particular problem for cultivated agricultural and horticultural crops where it can significantly decrease yields. Like many species of Ambrosia, A. trifida produces pollen which is allergenic and can induce allergic rhinitis, fever, or dermatitis. A. trifida is extremely competitive and can also decrease native biodiversity. A. trifida is a declared noxious weed in its native range in California, Delaware, Illinois and New Jersey, USA and is also a quarantine weed in Poland and Russia.

Taxonomic Tree

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

Notes on Taxonomy and Nomenclature

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A. trifida was described by Linnaeus (1753: 988) as one of the four listed Ambrosia species (the other three species are: A. artemisiifolia L., A. elatior L., and A. maritima L.). The lectotype was designated by Reveal in Jarvis and Turland (1998: 351) on a specimen preserved at LINN (The Linnean Society, 2016)

According to USDA-NRCS (2016) two subspecies exist; A. trifida var. texana (Texan great ragweed) and A. trifida var. trifida (great ragweed). These subspecies have different distrubtions within North America, with A. trifida var. trifida being present in most states.

Description

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A. trifida is an annual herb (therophyte), (30-)150-400 cm tall. Stems erect, branched or not. Leaves opposite, with blades rounded, deltate or elliptic [40-150(-250)×(10-)30-70(-200) mm], palmately 2-5-lobed, lobes with margins toothed, sparsely pubescent and glandular-dotted on both faces, petioled [petiole (10-)25-30(-70) mm long]. Flowers arranged in capitula, the male capitula forming a terminal leafless spike-like or raceme-like inflorescences at the end of the branches, the female capitula clustered at the base of the male inflorescences (pistillate flowers are tubular and without pappi); anthers yellow; ovary inferior with one ovule. Fruit (achene) pyramidal, (5-)6-12 mm long, brown to gray, glaborus or slightly pubescent, with 4-5 usually distal spines.

Distribution

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A. trifida is found primarily in temperate areas around the world and is native to eastern North America; it is found throughout much of the USA and southern Canada. In Canada, this weed ranges from Nova Scotia westward to the Northwest Territory. Within the USA, it is most common in the mid-Atlantic states and the Ohio and Mississippi River valleys.

A. trifida is not currently present in Africa (CJB, 2016), South America or Australasia (Council of Heads of Australasian Herbaria, 2016).

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.

Continent/Country/RegionDistributionLast ReportedOriginFirst ReportedInvasiveReferenceNotes

Asia

ChinaPresentIntroducedXie et al., 2000; EPPO, 2014; USDA-ARS, 2016
-HebeiPresentIntroducedMa and Liu, 2002; Wu et al., 2011; EPPO, 2014
-HeilongjiangPresentIntroduced Invasive Wu et al., 2011; EPPO, 2014
-HubeiPresentIntroduced Invasive EPPO, 2014
-HunanPresentIntroduced Invasive Wu et al., 2011; EPPO, 2014
-JiangxiPresentIntroduced Invasive Wu et al., 2011; EPPO, 2014
-JilinPresentIntroduced Invasive Wu et al., 2011; EPPO, 2014
-LiaoningPresentIntroduced Invasive Wu et al., 2011; EPPO, 2014
-ShandongPresentIntroduced Invasive Wu et al., 2011; EPPO, 2014
-SichuanPresentIntroduced Invasive Wu et al., 2011; EPPO, 2014
-ZhejiangPresentIntroduced Invasive Wu et al., 2011; EPPO, 2014
Georgia (Republic of)PresentIntroducedEPPO, 2014; Euro+Med, 2016
IsraelPresentIntroducedEPPO, 2014; USDA-ARS, 2016
JapanPresentIntroducedYamazaki et al., 2000; EPPO, 2014; USDA-ARS, 2016
Korea, Republic ofWidespreadShim et al., 1998; EPPO, 2014

North America

CanadaPresentNative
-AlbertaPresentNativeMulligan, 2000; Strother, 2006; EPPO, 2014; USDA-ARS, 2016; USDA-NRCS, 2016Ambrosia trifida L. var. trifida
-British ColumbiaPresentNativeMulligan, 2000May be extant
-ManitobaPresentNativeMulligan, 2000; Strother, 2006; EPPO, 2014; USDA-ARS, 2016; USDA-NRCS, 2016Ambrosia trifida L. var. trifida
-New BrunswickPresentNativeMulligan, 2000; Strother, 2006; EPPO, 2014; USDA-ARS, 2016; USDA-NRCS, 2016Ambrosia trifida L. var. trifida
-Nova ScotiaPresentNativeMulligan, 2000; Strother, 2006; EPPO, 2014; USDA-ARS, 2016; USDA-NRCS, 2016Ambrosia trifida L. var. trifida
-OntarioPresentNativeMulligan, 2000; Strother, 2006; EPPO, 2014; USDA-ARS, 2016; USDA-NRCS, 2016Ambrosia trifida L. var. trifida
-Prince Edward IslandPresentNativeStrother, 2006; EPPO, 2014; USDA-ARS, 2016; USDA-NRCS, 2016Ambrosia trifida L. var. trifida
-QuebecPresentNativeMulligan, 2000; Strother, 2006; EPPO, 2014; USDA-ARS, 2016; USDA-NRCS, 2016Ambrosia trifida L. var. trifida
-SaskatchewanPresentNativeMulligan, 2000; Strother, 2006; EPPO, 2014; USDA-ARS, 2016; USDA-NRCS, 2016Ambrosia trifida L. var. trifida
MexicoPresentStrother, 2006; EPPO, 2014; USDA-ARS, 2016; USDA-NRCS, 2016
USAPresentNativeUva et al., 1997; Strother, 2006; EPPO, 2014; USDA-ARS, 2016; USDA-NRCS, 2016
-AlabamaPresentNativeStrother, 2006; EPPO, 2014; USDA-ARS, 2016; USDA-NRCS, 2016Ambrosia trifida L. var. trifida
-ArizonaPresentNativeStrother, 2006; EPPO, 2014; USDA-NRCS, 2016Ambrosia trifida L. var. texana and Ambrosia trifida L. var. trifida
-ArkansasPresentNativeStrother, 2006; EPPO, 2014; USDA-NRCS, 2016Ambrosia trifida L. var. trifida
-CaliforniaPresentNativeStrother, 2006; EPPO, 2014; USDA-NRCS, 2016Ambrosia trifida L. var. trifida
-ColoradoPresentNativeStrother, 2006; EPPO, 2014; USDA-ARS, 2016; USDA-NRCS, 2016Ambrosia trifida L. var. trifida
-ConnecticutPresentNativeStrother, 2006; EPPO, 2014; USDA-NRCS, 2016Ambrosia trifida L. var. trifida
-DelawarePresentNativeStrother, 2006; EPPO, 2014; USDA-NRCS, 2016Ambrosia trifida L. var. trifida
-District of ColumbiaPresentNativeStrother, 2006; USDA-NRCS, 2016Ambrosia trifida L. var. trifida and Ambrosia trifida L. var. trifida
-FloridaPresentNativeStrother, 2006; EPPO, 2014; USDA-NRCS, 2016Ambrosia trifida L. var. trifida
-GeorgiaPresentNativeStrother, 2006; EPPO, 2014; USDA-ARS, 2016; USDA-NRCS, 2016Ambrosia trifida L. var. trifida
-IdahoPresentNativeStrother, 2006; EPPO, 2014; USDA-NRCS, 2016Ambrosia trifida L. var. texana and Ambrosia trifida L. var. trifida
-IllinoisPresentNativeStrother, 2006; EPPO, 2014; USDA-ARS, 2016; USDA-NRCS, 2016Ambrosia trifida L. var. trifida
-IndianaPresentNativeStrother, 2006; EPPO, 2014; USDA-ARS, 2016; USDA-NRCS, 2016Ambrosia trifida L. var. trifida
-IowaPresentNativeStrother, 2006; EPPO, 2014; USDA-ARS, 2016; USDA-NRCS, 2016Ambrosia trifida L. var. trifida
-KansasPresentNativeStrother, 2006; EPPO, 2014; USDA-ARS, 2016; USDA-NRCS, 2016Ambrosia trifida L. var. texana and Ambrosia trifida L. var. trifida
-KentuckyPresentNativeStrother, 2006; EPPO, 2014; USDA-ARS, 2016; USDA-NRCS, 2016Ambrosia trifida L. var. trifida
-LouisianaPresentNativeStrother, 2006; EPPO, 2014; USDA-ARS, 2016; USDA-NRCS, 2016Ambrosia trifida L. var. texana and Ambrosia trifida L. var. trifida
-MainePresentNativeStrother, 2006; EPPO, 2014; USDA-NRCS, 2016Ambrosia trifida L. var. trifida
-MarylandPresentNativeStrother, 2006; EPPO, 2014; USDA-ARS, 2016; USDA-NRCS, 2016Ambrosia trifida L. var. trifida
-MassachusettsPresentNativeStrother, 2006; EPPO, 2014; USDA-NRCS, 2016
-MichiganPresentNativeStrother, 2006; EPPO, 2014; USDA-ARS, 2016; USDA-NRCS, 2016Ambrosia trifida L. var. trifida
-MinnesotaPresentNativeStrother, 2006; EPPO, 2014; USDA-ARS, 2016; USDA-NRCS, 2016Ambrosia trifida L. var. trifida
-MississippiPresentNativeStrother, 2006; EPPO, 2014; USDA-ARS, 2016; USDA-NRCS, 2016Ambrosia trifida L. var. texana and Ambrosia trifida L. var. trifida
-MissouriPresentNativeStrother, 2006; EPPO, 2014; USDA-ARS, 2016; USDA-NRCS, 2016Ambrosia trifida L. var. texana and Ambrosia trifida L. var. trifida
-MontanaPresentNativeStrother, 2006; EPPO, 2014; USDA-ARS, 2016; USDA-NRCS, 2016Ambrosia trifida L. var. trifida
-NebraskaPresentNativeStrother, 2006; EPPO, 2014; USDA-ARS, 2016; USDA-NRCS, 2016Ambrosia trifida L. var. trifida
-New HampshirePresentNativeStrother, 2006; EPPO, 2014; USDA-NRCS, 2016Ambrosia trifida L. var. trifida
-New JerseyPresentNativeStrother, 2006; EPPO, 2014; USDA-NRCS, 2016Ambrosia trifida L. var. trifida
-New MexicoPresentNativeStrother, 2006; EPPO, 2014; USDA-NRCS, 2016Ambrosia trifida L. var. texana and Ambrosia trifida L. var. trifida
-New YorkPresentNativeStrother, 2006; EPPO, 2014; USDA-NRCS, 2016Ambrosia trifida L. var. trifida
-North CarolinaPresentNativeStrother, 2006; EPPO, 2014; USDA-ARS, 2016; USDA-NRCS, 2016Ambrosia trifida L. var. trifida
-North DakotaPresentNativeStrother, 2006; EPPO, 2014; USDA-ARS, 2016; USDA-NRCS, 2016Ambrosia trifida L. var. trifida
-OhioPresentNativeStrother, 2006; EPPO, 2014; USDA-ARS, 2016; USDA-NRCS, 2016Ambrosia trifida L. var. trifida
-OklahomaPresentNativeStrother, 2006; EPPO, 2014; USDA-ARS, 2016; USDA-NRCS, 2016Ambrosia trifida L. var. texana and Ambrosia trifida L. var. trifida
-OregonPresentNativeStrother, 2006; EPPO, 2014; USDA-NRCS, 2016Ambrosia trifida L. var. texana and Ambrosia trifida L. var. trifida
-PennsylvaniaPresentNativeStrother, 2006; EPPO, 2014; USDA-ARS, 2016; USDA-NRCS, 2016Ambrosia trifida L. var. trifida
-Rhode IslandPresentNativeStrother, 2006; EPPO, 2014; USDA-NRCS, 2016
-South CarolinaPresentNativeStrother, 2006; EPPO, 2014; USDA-ARS, 2016; USDA-NRCS, 2016Ambrosia trifida L. var. trifida
-South DakotaPresentNativeStrother, 2006; EPPO, 2014; USDA-ARS, 2016; USDA-NRCS, 2016Ambrosia trifida L. var. trifida
-TennesseePresentNativeStrother, 2006; EPPO, 2014; USDA-ARS, 2016; USDA-NRCS, 2016Ambrosia trifida L. var. trifida
-TexasPresentNativeStrother, 2006; EPPO, 2014; USDA-ARS, 2016; USDA-NRCS, 2016Ambrosia trifida L. var. texana and Ambrosia trifida L. var. trifida
-UtahPresentNativeStrother, 2006; EPPO, 2014; USDA-NRCS, 2016Ambrosia trifida L. var. trifida
-VermontPresentNativeStrother, 2006; EPPO, 2014; USDA-NRCS, 2016Ambrosia trifida L. var. trifida
-VirginiaPresentNativeStrother, 2006; EPPO, 2014; USDA-ARS, 2016; USDA-NRCS, 2016Ambrosia trifida L. var. trifida
-WashingtonPresentNativeStrother, 2006; EPPO, 2014; USDA-ARS, 2016; USDA-NRCS, 2016Ambrosia trifida L. var. trifida
-West VirginiaPresentNativeStrother, 2006; EPPO, 2014; USDA-ARS, 2016; USDA-NRCS, 2016Ambrosia trifida L. var. trifida
-WisconsinPresentNativeStrother, 2006; EPPO, 2014; USDA-ARS, 2016; USDA-NRCS, 2016Ambrosia trifida L. var. trifida
-WyomingPresentNativeStrother, 2006; EPPO, 2014; USDA-ARS, 2016; USDA-NRCS, 2016Ambrosia trifida L. var. trifida

Europe

AustriaPresentIntroducedEPPO, 2014; DAISIE, 2016; Euro+Med, 2016; USDA-ARS, 2016
BelarusPresentIntroducedEPPO, 2014; DAISIE, 2016; Euro+Med, 2016; USDA-ARS, 2016
BelgiumPresentIntroducedEPPO, 2014; DAISIE, 2016; Euro+Med, 2016; USDA-ARS, 2016
BulgariaPresentIntroducedEuro+Med, 2016
Czech RepublicPresentIntroducedRoyal Botanic Garden Edinburgh, 2003; EPPO, 2014; DAISIE, 2016; Euro+Med, 2016; USDA-ARS, 2016
DenmarkPresentIntroducedEPPO, 2014; DAISIE, 2016; Euro+Med, 2016; USDA-ARS, 2016
EstoniaPresentIntroducedEPPO, 2014; DAISIE, 2016; Euro+Med, 2016; USDA-ARS, 2016
FinlandPresentIntroducedDAISIE, 2016
FrancePresentIntroducedRoyal Botanic Garden Edinburgh, 2003; EPPO, 2014; DAISIE, 2016; Euro+Med, 2016; USDA-ARS, 2016
GermanyPresentIntroducedRoyal Botanic Garden Edinburgh, 2003; EPPO, 2014; DAISIE, 2016; Euro+Med, 2016; USDA-ARS, 2016
IrelandPresentIntroducedEPPO, 2014; DAISIE, 2016; Euro+Med, 2016; USDA-ARS, 2016
ItalyPresentIntroducedRoyal Botanic Garden Edinburgh, 2003; EPPO, 2014; DAISIE, 2016; Euro+Med, 2016
LatviaPresentIntroducedEPPO, 2014; DAISIE, 2016; Euro+Med, 2016; USDA-ARS, 2016
LithuaniaPresentIntroducedGudzinskas, 1993; EPPO, 2014; DAISIE, 2016; Euro+Med, 2016; USDA-ARS, 2016
LuxembourgPresentIntroducedEuro+Med, 2016
MoldovaPresentIntroducedEPPO, 2014; DAISIE, 2016; Euro+Med, 2016; USDA-ARS, 2016
NetherlandsPresentIntroducedEPPO, 2014; Euro+Med, 2016; USDA-ARS, 2016
NorwayPresentIntroducedEPPO, 2014; DAISIE, 2016
PolandPresentIntroducedKarnkowski, 2001; EPPO, 2014; Euro+Med, 2016; USDA-ARS, 2016
RomaniaPresentIntroducedEPPO, 2014; Euro+Med, 2016
Russian FederationPresentIntroducedBiodiversity, 2003; EPPO, 2014; Euro+Med, 2016; USDA-ARS, 2016
-Central RussiaPresentIntroducedEPPO, 2014; Euro+Med, 2016
-Eastern SiberiaPresentIntroducedEuro+Med, 2016
-Northern RussiaPresentIntroducedEuro+Med, 2016
-Southern RussiaPresentIntroducedEPPO, 2014; Euro+Med, 2016
-Western SiberiaPresentIntroducedEuro+Med, 2016
SerbiaPresentIntroducedEPPO, 2014; Euro+Med, 2016; USDA-ARS, 2016
SlovakiaPresentIntroducedRoyal Botanic Garden Edinburgh, 2003; EPPO, 2014; Euro+Med, 2016; USDA-ARS, 2016
SloveniaPresentIntroducedEPPO, 2014; Euro+Med, 2016; USDA-ARS, 2016
SpainPresentIntroducedEPPO, 2014; Euro+Med, 2016; USDA-ARS, 2016
SwedenPresentIntroducedDAISIE, 2016
SwitzerlandPresentIntroducedEPPO, 2014; Euro+Med, 2016; USDA-ARS, 2016
UKPresentIntroducedAllard, 1943; EPPO, 2014; DAISIE, 2016; Euro+Med, 2016; USDA-ARS, 2016
UkrainePresentIntroducedEPPO, 2014; DAISIE, 2016; Euro+Med, 2016; USDA-ARS, 2016
Yugoslavia (Serbia and Montenegro)PresentIntroducedEuro+Med, 2016

History of Introduction and Spread

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A. trifida is a neophyte which was introduced in Europe after the discovery of America. Detailed studies on the history of introduction however are not present. EPPO (2014) reports the year 1829 as the first date of introduction into Europe (Belgium), while concerning China, Qin et al. (2014) stated that this species was first introduced in 1935.

Introductions

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Introduced toIntroduced fromYearReasonIntroduced byEstablished in wild throughReferencesNotes
Natural reproductionContinuous restocking
Belgium North America 1826 Yes EPPO (2014)
China North America 1935 Yes Qin et al. (2014)

Risk of Introduction

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Further spread of A. trifida is highly likely, due to the risks of accidental movement seeds with agricultural equipment (locally) and as a contaminant of crop seeds. A. trifida is considered a noxious weed in many areas due to its intrusive nature and is a quarantine weed in Poland and Russia.

Habitat

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A. trifida is most prevelant in disturbed sites such as, damp soils, wastelands, uncultivated and cultivated lands (field crops), garden, ditches, roadsides, field margins, constructions sites, etc. (Uva et al., 1997). It may also be found colonising riverbanks, pastures and grasslands (Abul-Fatih and Bazzaz, 1979; Megyeri, 2011). A. trifida is common in flood plains and rare in low rainfall areas.

Habitat List

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CategorySub-CategoryHabitatPresenceStatus
Terrestrial
 
Terrestrial – ManagedCultivated / agricultural land Secondary/tolerated habitat Harmful (pest or invasive)
Protected agriculture (e.g. glasshouse production) Secondary/tolerated habitat Harmful (pest or invasive)
Managed forests, plantations and orchards Present, no further details Harmful (pest or invasive)
Managed grasslands (grazing systems) Present, no further details
Disturbed areas Principal habitat Harmful (pest or invasive)
Disturbed areas Principal habitat Natural
Rail / roadsides Principal habitat Harmful (pest or invasive)
Rail / roadsides Principal habitat Natural
Urban / peri-urban areas Principal habitat Harmful (pest or invasive)
Urban / peri-urban areas Principal habitat Natural
Terrestrial ‑ Natural / Semi-naturalNatural forests Present, no further details Harmful (pest or invasive)
Natural grasslands Principal habitat Harmful (pest or invasive)
Natural grasslands Principal habitat Natural
Riverbanks Principal habitat Harmful (pest or invasive)
Riverbanks Principal habitat Natural
Wetlands Present, no further details Harmful (pest or invasive)
Freshwater
Rivers / streams Principal habitat Harmful (pest or invasive)
Rivers / streams Principal habitat Natural

Hosts/Species Affected

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A. trifida is a weed of cultivated agronomic and horticultural crops such as species of Sorghum, Glycine max (soybean), Helianthus annuus (sunflower), Phaseolus spp (beans), Zea mays (maize), species of Triticum (wheat) and Gossypium hirsutum (cotton) (EPPO, 2014). It is extremely competitive and is especially difficult to control in many broadleaved crops. Experiments carried out by Baysinger and Sims (1991) in Missouri, USA, found that over two years dense populations of A. trifida reduced soybean seed yields by about 50%. A 55% reduction in corn yields in Michigan have also been recorded (Michigan State University, 2016).

Growth Stages

Top of page Flowering stage, Fruiting stage, Seedling stage, Vegetative growing stage

Biology and Ecology

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Genetics

A. trifida is a taxon with 2n = 24, 48 (Strother, 2006). A hybrid was described with A. artemisiifolia (A. × helenae Rouleau) (Strother, 2006). Hybrids were found to have somatic chromosome numbers ranging from 2n = 27 to 2n = 33 (Bassett and Crompton, 1982).

Reproductive Biology

Each A. trifida plant can produce up to 10,300 seeds, while in soybeans and corn crops one plant can produce 1900-5500 seeds (Michigan State University, 2016). Pollination is mainly performed by wind, the pollen being small (20-30 µm), tricolporate, sphaerical, with 60-65 spines (Bassett and Crompton 1982). It has been estimated that one plant can produce 10 million pollen grains per day and one billion pollen grains during its lifetime (Johnson et al., 2007). The stigmas protrude and are receptive prior to the shedding of pollen in the male flowers (Bassett and Crompton, 1982).

Physiology and Phenology

In the native range in the USA, seeds generally begin to mature in mid-August (Uva et al., 1997). Most seeds fall near the parent plant, but some can disperse long distances with water, animals, and human activities. Most germination in the field occurs early to mid-spring and at soil depths to 16 cm, optimal 2 cm (Bassett and Crompton, 1982). Germination rarely occurs on the soil surface. Seedlings emerge in mid to late spring. Seedlings emerging from shallow depths are most likely to survive as they compete with other species for light. Mature seeds are usually dormant and require a cold, moist period to germinate. Seeds can germinate in a wide range of temperatures (8-41°C), but with an optimum range of 10-24°C (Abul-Fatih and Bazzaz, 1979).

Detailed study on seed germination of A. trifida by Abul-Fatih (1977) found that A. trifida usually produced seeds of various sizes. Large seed was able to germinate under relatively cold temperatures, a wide range of moisture regimes and soil depths. Small seed, which have smaller energy reserves, must germinate and establish rapidly during favourable periods if the seedling is to survive longer than other competing summer annuals.

A. trifida plants produce new stems and inflorescences when cut in late July and August.

Environmental Requirements

A. trifida occurs in a wide range of rainfall zones, but generally prefers moister soil with a summer rainfall regime. Mean monthly temperatures can range from 5°C to 30°C and it is fairly indifferent to soil types.

Climate

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ClimateStatusDescriptionRemark
BS - Steppe climate Preferred > 430mm and < 860mm annual precipitation
BW - Desert climate Preferred < 430mm annual precipitation
Cf - Warm temperate climate, wet all year Preferred Warm average temp. > 10°C, Cold average temp. > 0°C, wet all year
Cs - Warm temperate climate with dry summer Preferred Warm average temp. > 10°C, Cold average temp. > 0°C, dry summers
Cw - Warm temperate climate with dry winter Preferred Warm temperate climate with dry winter (Warm average temp. > 10°C, Cold average temp. > 0°C, dry winters)
Df - Continental climate, wet all year Preferred Continental climate, wet all year (Warm average temp. > 10°C, coldest month < 0°C, wet all year)

Air Temperature

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Parameter Lower limit Upper limit
Absolute minimum temperature (ºC) -20
Mean annual temperature (ºC) 5 20
Mean maximum temperature of hottest month (ºC) 15 30
Mean minimum temperature of coldest month (ºC) -10 2

Rainfall

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ParameterLower limitUpper limitDescription
Dry season duration07number of consecutive months with <40 mm rainfall
Mean annual rainfall4002500mm; lower/upper limits

Natural enemies

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Natural enemyTypeLife stagesSpecificityReferencesBiological control inBiological control on
Cercospora Pathogen
Entyloma compositarum Pathogen Leaves not specific
Euaresta bella Herbivore Inflorescence not specific Released in Russia
Euaresta festiva Herbivore Inflorescence not specific Released in Russia
Papaipema nebris Herbivore
Protomyces gravidus Pathogen Stems not specific
Pseudomonas syringae pv. tagetis Pathogen Leaves/Stems not specific
Puccinia xanthi f.sp. ambrosid-trifidae Pathogen Leaves to species
Zygogramma suturalis Herbivore Leaves not specific

Notes on Natural Enemies

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Leaf-spot diseases (Cercospora spp.) are common in the field in the USA, but rarely have significant impact on the competitiveness of A. trifida plants. In Louisiana, A. trifida is noted as a host of Papaipema nebris (Alvarado et al., 1989) and stem galls are caused by Protomyces gravidus (Holcomb, 1995).

A number of other natural enemies have been identified as A. trifida is the subject of a biological control programme. Potential agents include Euaresta bella, E. festiva (Batra, 1979), Zygogramma suturalis (Xie et al., 2000) and the pathogens Puccinia xanthii f.sp. ambrosid-trifidae and Pseudomonas syringae pv. tagetis (Batra, 1981).

Means of Movement and Dispersal

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Natural Dispersal

A. trifida produces a large number of seeds which are dispersed by flood waters and with the wind.

Accidental Introduction

Seeds of A. trifida may accidentally be introduced into new areas with seeds or on cultivation and harvesting equipment.

Impact Summary

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CategoryImpact
Animal/plant collections None
Animal/plant products None
Biodiversity (generally) Negative
Crop production Negative
Economic/livelihood Negative
Environment (generally) Negative
Fisheries / aquaculture None
Forestry production None
Human health Negative
Livestock production None
Native fauna None
Native flora None
Other None
Rare/protected species None
Tourism None
Trade/international relations None
Transport/travel None

Economic Impact

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A. trifida is a weed of cultivated agronomic and horticultural crops and as such it will compete for space and nutrients resulting in a decrease in crop yield (Xie et al., 2000). It is a particular problem in corn and soybean where 50% yield losses have been recorded (Weaver, 2003; Regnier et al., 2016). In addition, increased economic costs may result for the increased application of herbicides.

A positive impact may be seen with a noted decrease in the numbers of plant-parasitic nematodes found in soybean fields where A. trifida is present (Wang et al., 1998).

Environmental Impact

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Impact on Biodiversity

A. trifida can behave as a dominant species throughout the entire growing season. It is often one of the first plants to emerge in early spring and as a result has an initial competitive advantage. It competes for resources (space, nutrients, light, water, etc.) with native species and as a result it may cause a decrease in biodiversity.

Social Impact

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A. trifida produces pollens which have morphological characteristics which result in it being an aeroallergen causing rhinitis, fever, or dermatitis (D’Amato et al., 2007). The impact of this, compared to similar and more widespread Ambrosia species such as A. artemisiifolia, is much lower.

Risk and Impact Factors

Top of page Invasiveness
  • Invasive in its native range
  • Proved invasive outside its native range
  • Abundant in its native range
  • Highly adaptable to different environments
  • Is a habitat generalist
  • Tolerates, or benefits from, cultivation, browsing pressure, mutilation, fire etc
  • Pioneering in disturbed areas
  • Tolerant of shade
  • Highly mobile locally
  • Fast growing
  • Has high reproductive potential
  • Has propagules that can remain viable for more than one year
Impact outcomes
  • Ecosystem change/ habitat alteration
  • Increases vulnerability to invasions
  • Negatively impacts agriculture
  • Negatively impacts human health
  • Negatively impacts animal health
  • Reduced native biodiversity
  • Threat to/ loss of native species
Impact mechanisms
  • Allelopathic
  • Causes allergic responses
  • Competition - monopolizing resources
  • Induces hypersensitivity
  • Rapid growth
Likelihood of entry/control
  • Highly likely to be transported internationally accidentally
  • Difficult/costly to control

Uses

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Social Benefit

A. trifida has little utility. The leaves have medicinal traditions that include its uses as an astringent, emetic, and febrifuge and it may be grown as an ornamental, but is not widely used for that purpose because of its unattractive flowers and rough, robust vegetative growth.

Similarities to Other Species/Conditions

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A. trifida can be easily distinguished from the other annual species belonging to the genus Ambrosia by the leaves which are palmate, while in the other related taxa (A. bidentata, A. acanthicarpa, and A. artemisiifolia) the blades are pinnate. The flowering heads and fruit of A. artemisiifolia are similar but smaller than those of A. trifida. The leaves of A. artemisiifolia are usually twice divided and not 3-5 lobed, and the overall plant size is generally much smaller.

When a large number of the leaves of A. trifida are unlobed, it can appear similar to Xanthium strumarium or Helianthus annuus; however, the leaves of these species are mostly alternate, whereas those of A. trifida are opposite.

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.

Control

Mechanical Control

Tillage is effective for control of seedlings of A. trifida because of their early emergence in relation to many other summer annual weeds (tillage is less effective in populations where plants are larger). Under moist soil conditions, plants may be 'transplanted' and begin growing in another area. Hand-pulling can be effective for seedlings, especially in gardens and other small plots. Repeated mowing will effectively reduce seed production but will not eliminate A. trifida. If allowed to approach maturity it pays to hand-pull the weed, because the stout, woody stalks dull and break the blades of mowers and harvesters, and clog threshing machines. Control of A. trifida using electrical discharges proved to be good to excellent (Rasmusson et al., 1980).

Biological Control

Surveys of potential biocontrol agents of A. trifida began in California in 1967 (Goeden, 1978). Euaresta bella and E. festiva have been released in Russia from 1976 (Batra, 1979) but are not now known to have established (Julien and Griffiths, 1998). Puccinia xanthii forma specialis ambrosid-trifidae was found to be species-specific and a potential biocontrol agent (Batra, 1981). Limited research has been made on biological control with Zygogramma suturalis (Coleoptera: Chrysomelidae); introduced into China from Canada and the former USSR (Xie et al., 2000). The bacterial pathogen Pseudomonas syringae pv. tagetis is the causal agent of a disease characterized by apical chlorosis on several members of Asteraceae, and this potential biological control continues to be researched.

Biocontrol programmes are in place for a closely related Ambrosia species. Introductions of biological control agents have been made against A. artemisiifolia in Australia, China, Georgia, Russia and Yugoslavia and against A. pilyostachya in Kazakhstan and Russia (Julien and Griffiths, 1998). No doubt some of the successfully introduced agents also attacked A. trifida if it was present, as most the majority are specific only to the genus.

Chemical Control

Application of atrazine, chlorimuron, and imazaquin are effective pre-emergence herbicides for control of A. trifida. The post-emergence herbicides acifluorfen, bentazone, dicamba, glyphosate, imazethapyr and 2,4-D have been recommended (Weed Science Society of America, 2003).

Glyphosate will control plants up to six inches in height. Tank mixing 2,4-D with glyphosate is also useful in controling A. trifida. However, biotypes of A. trifida have been found to be resistant to ALS (acetolactate synthase)-inhibitor herbicides in the USA since 1998 (Weed Science Society of America, 2003).

Gaps in Knowledge/Research Needs

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Further research is required to investigate the molecular differences between native vs. alien populations of A. trifida. In addition to this detailed phytosociological studies on non-native areas in which A. trifida is naturalized/invasive could be conducted.

References

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Batra SWT, 1979. Reproductive behavior of Euaresta bella and E. festiva (Diptera: Tephritidae), potential agents for the biological control of adventive North American ragweeds (Ambrosia spp.) in Eurasia. Journal of the New York Entomological Society, 87(2):118-125.

Batra SWT, 1981. Puccinia xanthii forma specialis ambrosid-trifidae. A microcyclic rust for the biological control of giant ragweed, Ambrosia trifida (Compositae). Mycopathologia, 72(2):61-64

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Contributors

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22/11/2016 Updated by:

Duilio Iamonico, University of Rome Sapienza, Rome, Italy

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