Pacific Island Ecosystems at Risk (PIER)

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Parthenium hysterophorus
L., Asteraceae
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Present on Pacific Islands?  yes

Primarily a threat at high elevations?  no

Risk assessment results:  Reject, score: 18 (Go to the risk assessment)

Common name(s): [more details]

Chinese: yin jiao ju

English: bitterweed, carrot grass, false ragweed, feverfew, parthenium weed, ragweed parthenium, Santa Maria, whitetop

French: fausse camomille

Spanish: escoba amarga

Habit:  herb

Description:  "Taprooted annual herbs 3-10 dm tall; stems unbranched in lower part, branched in upper part, longitudinally striate, hirsute.  Lower leaves in a basal rosette, these deciduous at maturity and stem leaves remaining, 3-20 cm long, 2-10 cm wide, bipinnatifid or pinnatifid.  Heads small, numerous in open panicles; rays white, 0.6 mm long; disk corollas cream-colored, ca. 1 mm long; pappus of 2 petaloid scales inserted close to the corolla on either side, entire or notched.  Achenes black, obovate, 2-2.5 mm long"  (Wagner et al., 1999; p. 347).

Description from the Flora of China online.
Description from the Flora of North America online.
Description from the Digital Flora of Taiwan.

Habitat/ecology:  "A pioneer species it invades grazing land, disturbed areas, roadsides and cultivated areas" (Smith, 2002; p. 64). "A weed of croplands, pastures, and natural and recreation areas.  Can cause 90% reduction in carrying capacity of pastures.  Contains sesquiterpines and phonolics, which makes parthenium weed allelopathic (suppressive) and causes dermatitis and other allergic reactions in humans and livestock, especially horses.  High water requirement.  Does best in neutral to high pH soils, less prolific on other soils"  (Motooka et al., 2003). "In Hawai‘i, "naturalized in low elevation, dry pastures or along roadsides." (Wagner et al., 1999; p. 347). In New Caledonia, "espèce largement répandue et parfois envahissante" (MacKee, 1994; p. 37).  In Taiwan, "widely naturalized on open seashores and in lowland waste places throughout the island"  (Digital Flora of Taiwan).

Propagation:  "Seed is dispersed by wind, water, as a contaminant of harvested material and by vehicles, machinery or animals. Seeds are light and produced in large quantities, often within three weeks of germination" (Smith, 2002; p. 64).

Native range:  Tropical America, but widely naturalized.

Presence:

Pacific
Country/Terr./St. &
Island group
Location Cited status &
Cited as invasive &
Cited as cultivated &
Cited as aboriginal introduction?
Reference &
Comments
French Polynesia
French Polynesia Islands
French Polynesia Islands   Waterhouse, D. F. (1997) (p. 63)
French Polynesia
Marquesas Islands
Hiva Oa Island introduced
invasive
Lorence, David H./Wagner, Warren L. (2013)
French Polynesia
Marquesas Islands
Hiva Oa Island introduced
invasive
Florence, J./Chevillotte, H./Ollier, C./Meyer, J.-Y. (2013)
Naturalisée
French Polynesia
Society Islands
Raiatea (Havai) Island introduced
invasive
cultivated
Welsh, S. L. (1998) (p. 78)
Voucher cited: Moore 682
French Polynesia
Society Islands
Tahiti Island introduced
invasive
cultivated
Welsh, S. L. (1998) (p. 78)
Voucher cited: Grant 4514
French Polynesia
Society Islands
Tahiti Island introduced
invasive
Florence, J./Chevillotte, H./Ollier, C./Meyer, J.-Y. (2013)
Naturalisée
French Polynesia
Austral (Tubuai) Islands
Rurutu Island introduced
invasive
Florence, J./Chevillotte, H./Ollier, C./Meyer, J.-Y. (2013)
Voucher cited: J. Florence 6132 (PAP)
Naturalisée
State of Hawaii
Hawaiian Islands
Hawai‘i (Big) Island introduced
invasive
Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 347)
Kona. Voucher cited: Kawasaki s. n.
State of Hawaii
Hawaiian Islands
Kaua‘i Island introduced
invasive
Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 347)
State of Hawaii
Hawaiian Islands
Maui Island introduced
invasive
Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 347)
State of Hawaii
Hawaiian Islands
Moloka‘i Island introduced
invasive
Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 347)
State of Hawaii
Hawaiian Islands
O‘ahu Island introduced
invasive
Wagner, Warren L./Herbst, Derral R. (1995) (p. 16)
Voucher cited: E. Funk s.n. (BISH)
New Caledonia
Îles Loyauté (Loyalte Islands)
Îles Loyauté (Loyalty Islands) introduced
invasive
Tassin, Jacques (2005)
New Caledonia
Îles Loyauté (Loyalte Islands)
Île Maré introduced
invasive
MacKee, H. S. (1994) (p. 37)
Voucher cited: Sarasin 482 (Z)
New Caledonia
Îles Loyauté (Loyalte Islands)
Îles Ouvéa (Ouvea Atoll) introduced
invasive
MacKee, H. S. (1994) (p. 37)
Voucher cited: Däniker 2200
New Caledonia
Îles Loyauté (Loyalte Islands)
Île Tiga introduced
invasive
MacKee, H. S. (1994) (p. 37)
Voucher cited: MacKee 45864
New Caledonia
Îles Loyauté (Loyalte Islands)
Île Walpole introduced
invasive
MacKee, H. S. (1994) (p. 37)
Voucher cited: Cherrier in MacKee 43813
New Caledonia
Îles Loyauté (Loyalte Islands)
Île Walpole introduced
Renevier, Alain/Cherrier, Jean-Francois (1991) (p. 16)
Voucher cited: Cherrier in MacKee 44070
New Caledonia
New Caledonia
New Caledonia Islands introduced
invasive
Meyer, Jean-Yves (2000) (p. 100)
New Caledonia
New Caledonia
New Caledonia Islands introduced
invasive
Gargominy, Oliver/Bouchet, Philipe/Pascal, Michel/Jaffre, Tanguy/Tourneu, Jean-Christophe (1996) (p. 379)
Largement répandue et parfois envahissante.
New Caledonia
New Caledonia Archipelago
Île Grande Terre introduced
invasive
Tassin, Jacques (2005)
New Caledonia
New Caledonia Archipelago
Île Grande Terre introduced
invasive
MacKee, H. S. (1994) (p. 37)
Vouchers cited: Brousmiche 739, Blanchon 799 (NOU), MacKee 16068, MacKee 29584, MacKee 30768
New Caledonia
New Caledonia Archipelago
Île des Pins (Isle of Pines) introduced
invasive
Tassin, Jacques (2005)
New Caledonia
New Caledonia Archipelago
Île des Pins (Isle of Pines) introduced
invasive
MacKee, H. S. (1994) (p. 37)
Voucher cited: MacKee 23464
Vanuatu
New Hebrides Islands
Vanuatu (Republic of) introduced
invasive
Shine, C./Reaser, J. K./Gutierrez, A. T., eds. (2003) (p. 179)
Pacific Rim
Country/Terr./St. &
Island group
Location Cited status &
Cited as invasive &
Cited as cultivated &
Cited as aboriginal introduction?
Reference &
Comments
Australia
Australia (continental)
Northern Territory introduced
invasive
Smith, Nicholas M. (2002) (p. 64)
Found at Limmen Bight and the Borroloola region.
Australia
Australia (continental)
Queensland introduced
invasive
Smith, Nicholas M. (2002) (p. 64)
Central America
Central America (Pacific rim)
Guatemala (Republic of) native
U.S. Dept. Agr., Agr. Res. Serv. (2013)
Central America
Central America (Pacific rim)
Honduras (Republic of) native
U.S. Dept. Agr., Agr. Res. Serv. (2013)
China
China
China (People's Republic of) introduced
invasive
Zhengyi, Wu/Raven, Peter H./Deyuan, Hong (2013)
Fields, roadsides; below 1500 m. Guangdong, Guangxi, Guizhou, Yunnan.
China
China
Hong Kong introduced
invasive
Wu, Te-lin (2001) (p. 285)
In wasteland.
Japan
Japan
Japan (country) introduced
Mito, Toshikazu/Uesugi, Tetsuro (2004) (p. 190)
Mexico
Mexico
Mexico (United Mexican States) native
U.S. Dept. Agr., Agr. Res. Serv. (2013)
Taiwan
Taiwan Island
Taiwan Island introduced
invasive
Ching-I Peng, ed. (2013)
Indian Ocean
Country/Terr./St. &
Island group
Location Cited status &
Cited as invasive &
Cited as cultivated &
Cited as aboriginal introduction?
Reference &
Comments
Mauritius
Mautitius Islands (Mauritius and Rodrigues)
Mauritius Island   Holm, Leroy/Pancho, Juan V./Herberger, James P./Plucknett, Donald L. (1979) (p. 266)
French Territory of Mayotte
Mayotte Islands
Mayotte Island introduced
invasive
Comité français de l'Union Internationale pour la Conservation de la Nature en France (2013)
Envahissant principalement dans les milieux perturbés.

Comments:  Moderately invasive in New Caledonia (Meyer, 2000; p. 100). A "weed of national significance" in Australia. "A declared noxious weed in Queensland, Northern Territory and Western Australia" (Smith, 2002; p. 64).

Control: 

Physical:  "Australian authorities have imposed strict quarantines on contaminated equipment and stock to avoid spread into new areas.  Since the weed only invades bare soil, good pasture management is effective for prevention"  (Motooka et al., 2003).

Chemical: "Effective herbicides include 2,4-D, atrazine, hexazinone, and metsulfuron. Triclopyr is effective on most Asteraceae"  (Motooka et al., 2003).

Biological:  "Australian scientists report the moth Epiblema strenuana promising.  They are also looking at the rust Puccina abrupta var. parthenenicicola and fungi that affect the weed in Mexico"  (Motooka et al., 2003).


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This page was created on 26 OCT 2001 and was last updated on 8 JAN 2013.