Chromolaena odorata (L.) R.M.King & H.Robinson, Asteraceae

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Present on Pacific Islands?  yes

Primarily a threat at high elevations?  no

Risk assessment results:  High risk, score: 28 (Go to the risk assessment)

Other Latin names:  Eupatorium odoratum L.

Common name(s): [more details]

Chamorro: masigsig

Chinese: fei ji cao

Chuukese: otuot

English: Christmasbush, Jack in the bush, Siam weed, bitter bush, butterfly weed, chromolaena, devilweed, hagonoy, paraffin-weed, triffid weed

Filipino: agonoi, huluhagonoi

French: fleurit-Noël, herbe du Laos

Kosraean: mahsrihsrihk

Palauan: kesengesil, ngesngesil

Pohnpeian: masigsig, masikisik, wisolmat, wisolmat en rehnwel

Spanish: chimuyo, crucito, hierba de chiva, paleca, rey del todo

Habit:  shrub

Description:  "Big bushy herb or subshrub with long rambling (but not twining) branches; stems terete, pubescent; leaves opposite, flaccid-membranous, velvety-pubescent, deltoid-ovate, acute, 3-nerved, very coarsely toothed, each margin with 1-5 teeth, or entire in youngest leaves; base obtuse or subtruncate but shortly decurrent; petiole slender, 1-1.5 cm long; blade mostly 5-12 cm long, 3-6 cm wide, capitula in sub-corymbose axillary and terminal clusters; peduncles 1-3 cm long, bracteate; bracts slender, 10-12 mm long; involucre of about 4-5 series of bracts, pale with green nerves, acute, the lowest ones about 2 mm long, upper ones 8-9 mm long, all acute, distally ciliate, flat, appressed except the extreme divergent tip; florets all alike (disc-florets), pale purple to dull off-white, the styles extending about 4 mm beyond the apex of the involucre, spreading radiately; receptacle very narrow; florets about 20-30 or a few more, 10-12 mm long; ovarian portion 4 mm long; corolla slender trumpet form; pappus of dull white hairs 5 mm long; achenes glabrous or nearly so"  (Stone, 1970; p. 581).

Habitat/ecology:  It grows in many soil types but prefers well-drained soils. It does not tolerate shade and thrives well in open areas (Ecoport).  Forms dense stands which prevent establishment of other species, both due to competition and allelopathic effects.  Requires disturbance to become established.  When dry, is a flashy fuel which promotes wildland fires. 

"An opportunistic weed generally confined to forest edges and clearings.  It can form dense thickets in disturbed areas and may prevent recruitment of native plant species, thereby delaying successional processes.  Dense infestations can increase the intensity and frequency of fire, leading to further changes in the structure and composition of native plant communities.  C. odorata has the potential to colonise tropical and sub-tropical areas where annual rainfall exceeds 1000 mm per annum.  In its native habitat, the plant trives in tropical rainforest clarings and river flats, appearing early in the successional stage, rapidly establishing dense thickets and then gradually disappearing as the rainforest canopy closes over.  C. odorata can grow on most soils but prefers well-drained sites and will not grow in water-logged or saline soils.  Tree clearing for agriculture and other development appears to facilitate spread of the plant, which is quick to colonise roadsides, forest edges, plantations and pastures.  Agricultural districts, where original rainforest cover has been fragmented into small reserves and corridors, is particularly vulnerable to invasion."  (Csurhes & Edwards, 1998; p. 31-32).

"Croplands and neglected pastures, forest margins and disturbed rainforests; in well-drained soils" (Waterhouse & Mitchell, 1998; pp. 23-24).

Propagation:  Wind-dispersed seeds. Seeds also cling to hair, clothing and shoes. The tiny seeds can occur as a contaminant in imported seed or on vehicles and machinery. Vehicle traffic can spread the seed along roads. Can propagate vegetatively from stem and root fragments. (Waterhouse & Mitchell, 1998; pp. 23-24).

Native range:  "Native from Florida through the West Indies and from Texas through Central and South America to Argentina (Howard 1989, Liogier 1997). It has been accidentally or deliberately introduced and has naturalized throughout much of the tropics"  (Wildland shrubs of the United States and its territories).

Presence:

Pacific
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
Commonwealth of the Northern Mariana Islands (US) Northern Mariana Islands	Agrigan (Agrihan) Island	introduced	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1979) (p. 288)
Commonwealth of the Northern Mariana Islands (US) Northern Mariana Islands	Agrigan (Agrihan) Island	introduced invasive	Fosberg, F. R./Falanruw, M. V. C./Sachet, M.-H. (1975) (p. 42) Voucher cited: Falanruw 2191 (US)
Commonwealth of the Northern Mariana Islands (US) Northern Mariana Islands	Aguijan (Agiguan, Aguihan) Island	introduced	Raulerson, L. (2006) (p. 68)
Commonwealth of the Northern Mariana Islands (US) Northern Mariana Islands	Northern Mariana Islands	introduced invasive	Meyer, Jean-Yves (2000) (p. 102)
Commonwealth of the Northern Mariana Islands (US) Northern Mariana Islands	Pagan Island	introduced	Raulerson, L. (2006) (p. 68)
Commonwealth of the Northern Mariana Islands (US) Northern Mariana Islands	Pagan Island		Bishop Museum (Honolulu) (1984) (voucher ID: BISH 635249) Taxon name on voucher: Chromolaena odorata (L.) R.M.King & H.Robinson
Commonwealth of the Northern Mariana Islands (US) Northern Mariana Islands	Pagan Island		Bishop Museum (Honolulu) (1984) (voucher ID: BISH 1000070) Taxon name on voucher: Chromolaena odorata (L.) R.M.King & H.Robinson
Commonwealth of the Northern Mariana Islands (US) Northern Mariana Islands	Rota Island	introduced invasive	Space, James C./Waterhouse, Barbara/Denslow, Julie S./Nelson, Duane (2000) (p. 5)
Commonwealth of the Northern Mariana Islands (US) Northern Mariana Islands	Rota Island	introduced invasive	Fosberg, F. R./Falanruw, M. V. C. (1980) (pp. 209-210) Voucher cited: Fosberg & Moore 58215 (US)
Commonwealth of the Northern Mariana Islands (US) Northern Mariana Islands	Rota Island	introduced	Raulerson, L. (2006) (p. 68)
Commonwealth of the Northern Mariana Islands (US) Northern Mariana Islands	Rota Island		Bishop Museum (Honolulu) (1979) (voucher ID: BISH 438411) Taxon name on voucher: Chromolaena odorata (L.) R.M.King & H.Robinson
Commonwealth of the Northern Mariana Islands (US) Northern Mariana Islands	Rota Island		Bishop Museum (Honolulu) (1985) (voucher ID: BISH 573249) Taxon name on voucher: Chromolaena odorata (L.) R.M.King & H.Robinson
Commonwealth of the Northern Mariana Islands (US) Northern Mariana Islands	Rota Island		Bishop Museum (Honolulu) (1982) (voucher ID: BISH 593392) Taxon name on voucher: Chromolaena odorata (L.) R.M.King & H.Robinson
Commonwealth of the Northern Mariana Islands (US) Northern Mariana Islands	Tinian Island	introduced	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1979) (p. 288)
Commonwealth of the Northern Mariana Islands (US) Northern Mariana Islands	Tinian Island	introduced invasive	Fosberg, F. R./Falanruw, M. V. C. (1975) (p. 80) Voucher cited: Kondo 17 (BISH)
Commonwealth of the Northern Mariana Islands (US) Northern Mariana Islands	Tinian Island		Bishop Museum (Honolulu) (1952) (voucher ID: BISH 132061) Taxon name on voucher: Eupatorium odoratum L.
Commonwealth of the Northern Mariana Islands (US) Northern Mariana Islands	Tinian Island		Bishop Museum (Honolulu) (1985) (voucher ID: BISH 572581) Taxon name on voucher: Chromolaena odorata (L.) R.M.King & H.Robinson
Commonwealth of the Northern Mariana Islands (US) Northern Mariana Islands	Tinian Island		Bishop Museum (Honolulu) (1980) (voucher ID: BISH 588313) Taxon name on voucher: Chromolaena odorata (L.) R.M.King & H.Robinson
Commonwealth of the Northern Mariana Islands (US) Northern Mariana Islands	Tinian Island		Bishop Museum (Honolulu) (1982) (voucher ID: BISH 593646) Taxon name on voucher: Chromolaena odorata (L.) R.M.King & H.Robinson
Commonwealth of the Northern Mariana Islands (US) Saipan	Saipan Island	introduced	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1979) (p. 288)
Commonwealth of the Northern Mariana Islands (US) Saipan	Saipan Island	introduced invasive	Fosberg, F. R./Falanruw, M. V. C. (1975) (p. 80) Vouchers cited: Stone 5172 (UG), Courage 45 (US), Courage 60 (US), Fosberg 47714 (US)
Federated States of Micronesia Chuuk Islands	Tol Island	introduced invasive	Space, James C./Waterhouse, Barbara/Denslow, Julie S./Nelson, Duane/Mazawa, Thomas R. (2000) (p. 5)
Federated States of Micronesia Chuuk Islands	Weno (Moen) Island	introduced invasive	Space, James C./Waterhouse, Barbara/Denslow, Julie S./Nelson, Duane/Mazawa, Thomas R. (2000) (p. 5) Voucher: BMW 5789 (BISH, GUAM)
Federated States of Micronesia Chuuk Islands	Weno (Moen) Island		Bishop Museum (Honolulu) (2000) (voucher ID: BISH 687704) Taxon name on voucher: Chromolaena odorata (L.) R.M.King & H.Robinson
Federated States of Micronesia Kosrae Island	Kosrae Island	introduced invasive	Meyer, Jean-Yves (2000) (p. 90)
Federated States of Micronesia Kosrae Island	Kosrae Island	introduced invasive cultivated abo. intro.	Space, James C./Waterhouse, Barbara/Denslow, Julie S./Nelson, Duane/Waguk, Erick E. (2000) (p. 5) Voucher: BMW 5765 (BISH, BRI, GUAM)
Federated States of Micronesia Kosrae Island	Kosrae Island	introduced invasive	Lorence, David H./Flynn, Timothy (2010) (p. 13) Widely naturalized
Federated States of Micronesia Kosrae Island	Kosrae Island	introduced invasive	Josekutty, P. C./Wakuk, E. E./Joseph, M. J. (2002) (p. 62)
Federated States of Micronesia Kosrae Island	Kosrae Island		Bishop Museum (Honolulu) (2000) (voucher ID: BISH 687669) Taxon name on voucher: Chromolaena odorata (L.) R.M.King & H.Robinson
Federated States of Micronesia Kosrae Island	Kosrae Island		National Tropical Botanical Garden (U.S.A. Hawaii. Kalaheo.) (2005) (voucher ID: PTBG 44909) Taxon name on voucher: Chromolaena odorata
Federated States of Micronesia Kosrae Island	Kosrae Island	introduced invasive	Sanney, Jacob A. (2013) (p. 19) KCSO target species 2013
Federated States of Micronesia Pohnpei Islands	Pohnpei Island		Swarbrick, John T. (1997) (p. 89)
Federated States of Micronesia Pohnpei Islands	Pohnpei Island	introduced invasive	Meyer, Jean-Yves (2000) (p. 90)
Federated States of Micronesia Pohnpei Islands	Pohnpei Island	introduced invasive	Herrera, Katherine/Lorence, David H./Flynn, Timothy/Balick, Michael J. (2010) (p. 72) Vouchers cited: N.L.H. Krauss 1883 (BISH), N.L.H. Krauss 1899a (BISH), S. Perlman 21393 (PTBG) Invasive
Federated States of Micronesia Pohnpei Islands	Pohnpei Island	introduced invasive	Fosberg, F. R./Falanruw, M. V. C. (1980) (pp. 209-210) Voucher cited: Falanruw 3237 (US)
Federated States of Micronesia Pohnpei Islands	Pohnpei Island		Bishop Museum (Honolulu) (1987) (voucher ID: BISH 511189) Taxon name on voucher: Chromolaena odorata (L.) R.M.King & H.Robinson
Federated States of Micronesia Pohnpei Islands	Pohnpei Island		Bishop Museum (Honolulu) (1987) (voucher ID: BISH 511407) Taxon name on voucher: Chromolaena odorata (L.) R.M.King & H.Robinson
Federated States of Micronesia Yap Islands	Yap (Waqab) Island		Swarbrick, John T. (1997) (p. 89)
Federated States of Micronesia Yap Islands	Yap (Waqab) Island	introduced invasive	Meyer, Jean-Yves (2000) (p. 90)
Federated States of Micronesia Yap Islands	Yap (Waqab) Island	introduced invasive	Space, James C./Falanruw, Marjorie (1999) (p. Field notes.)
Guam Guam Island	Guam Island	introduced invasive	Stone, Benjamin C. (1970) (p. 581) Voucher cited: Stone 5172 (GUAM)
Guam Guam Island	Guam Island	introduced	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1979) (p. 288)
Guam Guam Island	Guam Island	introduced invasive	Meyer, Jean-Yves (2000) (p. 94)
Guam Guam Island	Guam Island		Bishop Museum (Honolulu) (1966) (voucher ID: BISH 438126) Taxon name on voucher: Eupatorium odoratum L.
State of Hawaii Hawaiian Islands	O‘ahu Island	introduced invasive	Frohlich, Danielle/Lau, Alex (2012) (pp. 30-31) Voucher cited: H. Pali U.S. Army 199 (BISH)
Marshall Islands Ralik Chain	Bikini (Pikinni) Atoll		Wagner, W. L./ Herbst, D. R./Weitzman, A./Lorence, D.H. (2013)
Marshall Islands Ralik Chain	Bikini (Pikinni) Atoll		National Tropical Botanical Garden (U.S.A. Hawaii. Kalaheo.) (2003) (voucher ID: PTBG 39896) Taxon name on voucher: Chromolaena odorata (L.) R.M.King & H.Robinson
Marshall Islands Ratak Chain	Majuro (Mãjro) Atoll	introduced invasive	Vander Velde, Nancy (2003) (p. 69) Recent introduction, subject of an eradication program (Nancy Vander Velde, pers. com.).
Palau Palau (Belau ) (main island group)	Angaur (Ngeaur) Island	introduced invasive	Space, James C./Waterhouse, Barbara/Miles, Joel E./Tiobech, Joseph/Rengulbai, Kashgar (2003) (pp. 8, 88)
Palau Palau (Belau ) (main island group)	Babeldaob Island	introduced invasive	Space, James C./Waterhouse, Barbara/Miles, Joel E./Tiobech, Joseph/Rengulbai, Kashgar (2003) (pp. 8, 84)
Palau Palau (Belau ) (main island group)	Babeldaob Island	introduced invasive	Lorence, David H./Flynn, Tim (2010) (p. 22) Voucher cited: Flynn 6363 (PTBG)
Palau Palau (Belau ) (main island group)	Babeldaob Island	introduced invasive	Space, James C./Lorence, David H./LaRosa, Anne Marie (2009) (p. 10)
Palau Palau (Belau ) (main island group)	Babeldaob Island		Bishop Museum (Honolulu) (1991) (voucher ID: BISH 609542) Taxon name on voucher: Chromolaena odorata (L.) R.M.King & H.Robinson
Palau Palau (Belau ) (main island group)	Babeldaob Island		Bishop Museum (Honolulu) (1988) (voucher ID: BISH 634810) Taxon name on voucher: Chromolaena odorata (L.) R.M.King & H.Robinson
Palau Palau (Belau ) (main island group)	Babeldaob Island		Beleu National Museum (Republic of Palau. Koror.) (2007) (voucher ID: BNM 4383) Taxon name on voucher: Chromolaena odorata (L.) R.M. King & H. Robinson
Palau Palau (Belau ) (main island group)	Babeldaob Island		Beleu National Museum (Republic of Palau. Koror.) (1988) (voucher ID: BNM 10200) Taxon name on voucher: Chromolaena odorata
Palau Palau (Belau ) (main island group)	Babeldaob Island		National Tropical Botanical Garden (U.S.A. Hawaii. Kalaheo.) (2007) (voucher ID: PTBG 48181) Taxon name on voucher: Chromalaena odorata (L.) R. M. King & H. Rob.
Palau Palau (Belau ) (main island group)	Babeldaob Island		National Tropical Botanical Garden (U.S.A. Hawaii. Kalaheo.) (1998) (voucher ID: PTBG 25473) Taxon name on voucher: Chromolaena odorata (L.) King & Rob.
Palau Palau (Belau ) (main island group)	Koror (Oreor) Island	introduced invasive	Space, James C./Waterhouse, Barbara/Miles, Joel E./Tiobech, Joseph/Rengulbai, Kashgar (2003) (pp. 8, 80)
Palau Palau (Belau ) (main island group)	Koror (Oreor) Island	introduced invasive	Lorence, David H./Flynn, Tim (2010) (p. 22)
Palau Palau (Belau ) (main island group)	Koror (Oreor) Island	introduced invasive	Space, James C./Lorence, David H./LaRosa, Anne Marie (2009) (p. 10)
Palau Palau (Belau ) (main island group)	Malakal (Ngemelachel) Island	introduced invasive	Space, James C./Waterhouse, Barbara/Miles, Joel E./Tiobech, Joseph/Rengulbai, Kashgar (2003) (pp. 8, 80)
Palau Palau (Belau ) (main island group)	Malakal (Ngemelachel) Island	introduced invasive	Space, James C./Lorence, David H./LaRosa, Anne Marie (2009) (p. 10)
Palau Palau (Belau ) (main island group)	Ngerkebesang Island	introduced invasive	Space, James C./Waterhouse, Barbara/Miles, Joel E./Tiobech, Joseph/Rengulbai, Kashgar (2003) (pp. 8, 80)
Palau Palau (Belau ) (main island group)	Peleliu (Beliliou) Island	introduced invasive	Space, James C./Waterhouse, Barbara/Miles, Joel E./Tiobech, Joseph/Rengulbai, Kashgar (2003) (pp. 8, 90)
Palau Palau (Belau ) (main island group)	Peleliu (Beliliou) Island	introduced invasive	Space, James C./Lorence, David H./LaRosa, Anne Marie (2009) (p. 10)
Palau Palau (Belau ) (main island group)	Peleliu (Beliliou) Island		Bishop Museum (Honolulu) (1994) (voucher ID: BISH 659854) Taxon name on voucher: Chromolaena odorata (L.) R.M.King & H.Robinson
Palau Rock Islands (Chelbacheb)	Ngidech Island	introduced invasive	Space, James C./Waterhouse, Barbara/Miles, Joel E./Tiobech, Joseph/Rengulbai, Kashgar (2003) (pp. 8, 92)
Papua New Guinea Admiralty Islands	Los Negros Island	invasive	Orapa, Warea (year unknown) Communication to Aliens listserver.
Papua New Guinea Bismarck Archipelago	New Britain Island	invasive	Orapa, Warea (year unknown) Communication to Aliens listserver.
Papua New Guinea Bismarck Archipelago	New Ireland Island	invasive	Orapa, Warea (year unknown) Communication to Aliens listserver.
Papua New Guinea Papua New Guinea (eastern New Guinea Island)	Papua New Guinea (eastern New Guinea Island)	introduced invasive	Waterhouse, B. M./Mitchell, A. A. (1998) (pp. 23-24)
Papua New Guinea Papua New Guinea (eastern New Guinea Island)	Papua New Guinea (eastern New Guinea Island)	introduced invasive	Henty, E. E./Pritchard, G. H. (1975) (p. 75) Gazelle Peninsula, East New Britain.
Philippines Philippine Islands	Philippine Islands	introduced invasive	Holm, Leroy G./Plucknett, D. L./Pancho, J. V./Herberger, J. P. (1977) (pp. 212-216)

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)	Queensland	introduced invasive	Waterhouse, B. M (2003) (pp. 479-480) Subject of eradication program.
Cambodia Cambodia	Cambodia (Kingdom of)	introduced invasive cultivated	U.S. Dept. Agr., Agr. Res. Serv. (2013) Naturalized
Central America Central America (Pacific rim)	Costa Rica (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
Central America Central America (Pacific rim)	El Salvador (Republic of)		Holm, Leroy G./Plucknett, D. L./Pancho, J. V./Herberger, J. P. (1977) (pp. 212-216)
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)
Central America Central America (Pacific rim)	Nicaragua (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
Central America Central America (Pacific rim)	Panama (Republic of)		Holm, Leroy G./Plucknett, D. L./Pancho, J. V./Herberger, J. P. (1977) (pp. 212-216)
China China	China (People's Republic of)	introduced invasive	Zhengyi, Wu/Raven, Peter H./Deyuan, Hong (2013) Forest margins, roadsides, open disturbed land. Introduced in Hainan during World War II; naturalized in Fujian, Hainan, and Yunnan.
China China	China (People's Republic of)	introduced invasive	Li-ying, Li/Ren, Wang/Waterhouse, D. F. (1997) (pp. 172, 178)
China China	Hong Kong	introduced invasive	Wu, Te-lin (2001) (p. 281) As Eupatorium odoratum L. In wasteland.
Indonesia Indonesia	Indonesia (Republic of)	introduced invasive	U.S. Dept. Agr., Agr. Res. Serv. (2013) Naturalized
Indonesia Indonesia	West Papua Province (Indonesia) (western New Guinea Island) (formerly Irian Jaya)	introduced invasive	Waterhouse, B. M./Mitchell, A. A. (1998) (pp. 23-24)
Japan Japan	Japan	introduced	Mito, Toshikazu/Uesugi, Tetsuro (2004) (p. 190) As Eupatorium odoratum L.
Malaysia Malaysia	Malaysia (country of)	introduced invasive	U.S. Dept. Agr., Agr. Res. Serv. (2013) Naturalized
Mexico Mexico	Mexico (United Mexican States)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
Singapore Singapore	Singapore (Republic of)	introduced invasive	Chong, Kwek Yan/Tan, Hugh T. W./Corlett, Richard T. (2009) (p. 26) Naturalised
South America (Pacific rim) South America (Pacific rim)	Colombia	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
South America (Pacific rim) South America (Pacific rim)	Ecuador (Republic of) (continental)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
South America (Pacific rim) South America (Pacific rim)	Perú (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
Taiwan Taiwan Island	Taiwan Island	introduced invasive cultivated	Ching-I Peng, ed. (2013) "Introduced as a medicinal herb and naturalized in the south".
Thailand Thailand	Thailand (Kingdom of)	introduced invasive	U.S. Dept. Agr., Agr. Res. Serv. (2013) Naturalized
Vietnam Vietnam	Vietnam (Socialist Republic of)	introduced invasive cultivated	U.S. Dept. Agr., Agr. Res. Serv. (2013) Naturalized

Indian Ocean
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
Australia (Indian Ocean offshore islands) Cocos (Keeling) Islands	Cocos (Keeling) Islands	introduced invasive	Waterhouse, B. M (2003) (pp. 479-480)
British Indian Ocean Territory Chagos Archipelago	Diego Garcia Island	introduced invasive	Whistler, W. Arthur (1996) (p. 26)
British Indian Ocean Territory Chagos Archipelago	Diego Garcia Island		National Tropical Botanical Garden (U.S.A. Hawaii. Kalaheo.) (1995) (voucher ID: PTBG 37889) Taxon name on voucher: Chromolaena odorata (L.) R.M.King & H.Robinson
Mauritius Mautitius Islands (Mauritius and Rodrigues)	Mauritius Island	introduced invasive	U.S. Dept. Agr., Agr. Res. Serv. (2013) Naturalized

Also reported from
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
United States (continental except west coast) United States (other states)	United States (other states)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013) Texas
United States (continental except west coast) United States (other states)	USA (Florida)	native	Cronk, Q. C. B./Fuller, J. L. (2001) (p. 146)

Comments:  The University of Guam publishes a newsletter on Chromolaena odorata.

"A weed of plantation crops, pastures and an environmental weed" (Waterhouse & Mitchell, 1998; pp. 23-24).

On State of Hawaii noxious weed list. Subject of an eradication program in Queensland, Australia. A declared noxious weed in South Africa.

Control: 

Physical: "Manual slashing, use of bush-cutter or tractor-drawn implements are commonly used methods of control. Slashing causes rapid regeneration unless followed by other methods to suppress this weed for an extended period. Manual weeding is labour intensive. Use of tractor drawn equipment is limited to areas that are accessible." (Ecoport)

Chemical:  Chemical control using herbicides applied at the seedling stage or on early regrowth has given encouraging results. Triclopyr has proven to be the most effective. However, problems in herbicide use include (a) the high cost of the chemicals and their application, (b) ecological concerns and, (c) non-compatibility in many cropping and other environmental situations." (Ecoport)

"Remove all seed and flower heads the, leaving the rest of the plants intact, spray with a herbicide, probably 2,4-D Amine plus Picloram (sold as Tordon in Australia). The 2,4-D will kill off the top growth and the picloram will move through the soil, killing the root system."  (Rod Randall, communication to Aliens list server, 30 October 2000).

Biological: "Four insects have been released for biological control, the weevil Apion brunneonigrum, the fly Melanagromyza eupatoriella and two moths, Mescinia parvula and Pareuchaetes pseudoinsulata.  Of these, only the last has become established, fairly readily in Sri Lanka, Guam and other Micronesian islands, but with some difficulty in India and Sabah (Malaysia) and it has since spread unaided to the Philippines and Brunei.  It failed to become established in Thailand, Ghana, Nigeria and South Africa.  It has produced spectacular defoliation and death of many plants in Guam and striking but sporadic defoliation in Sri Lanka.  In India, populations have built up but damage has seldom been great.  Where established, it is heavily attacked by a range of predators and these are believed to have prevented successful establishment in several countries. 

"The eriophyid mite Acalitus adoratus causes abnormal growth of the epidermal hairs on young leaves and stems of C. odorata.  Although it was never purposely introduced, it was observed in Thailand in 1984 and the Philippines in 1987, but had probably been present for some years.  It is also widespread in Java and Sumatra, but there is no information from other Indonesian islands.  It is present in Yap and Palau in the Caroline Islands and was observed on Guam in November 1993 (R. Muniappan pers. comm.)"  (Waterhouse, 1994; pp. 39, 41).  Waterhouse (1994, pp. 37-53) also lists natural enemies of the species, the biology of the more promising ones, and the status of biological control in individual countries.

The biological control agent Pareuchaetes pseudoinsulata has been introduced into Guam, where it effectively defoliates pure stands. It is less successful in scattered plants and patches. It has also been introduced into Rota, Tinian, Aguijan, Palau, Kosrae, Pohnpei and Yap, but its present status on these islands is unknown. It has been introduced to Saipan where it seems to have been effective in reducing the problem to an occasional nuisance.

"Another natural enemy, Cecidochares connexa (Tephritidae) has been established in Palau and Guam" (Muniappan and Nandwani, 2002; p. 15).