Striga asiatica (L.) Kuntze, Orobanchaceae

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Present on Pacific Islands?  no

Primarily a threat at high elevations?  no

Other Latin names:  Buchnera asiatica L.; Striga lutea Lour.

Common name(s): [more details]

Chinese: du jiao jin

English: Asiatic witchweed, witchweed

Habit:  herb

Description:  "Erect, branched annual herb to 30 cm tall; root parasite on a wide range of hosts, with shallow roots connected to host by haustoria.  Stems terete below ground, square above, bristly.  Leaves green, sessile, linear, 10-40 - 1-4 mm, scabrid-hairy; lower leaves opposite, upper becoming scattered.  Inflorescence an erect, terminal spike 10-15 cm long.  Flowers sessile or shortly stalked, subtended by scabrid, linear bracts.  Calyx to 6 mm long, ribbed, unequally lobed.  Corolla to 11 mm long, lobed, 2-lipped; tube recurved and narrowing upwards, shortly hairy.  Flower colour varies from yellow through white to pink or red, with a tendency for regional colours (e.g. red in Africa).  Capsules black, ellipsoidal, 4 - 2 mm, 2-valved  Seeds minute, 0.2-0.3 mm long, ribbed, brown."  (Waterhouse & Mitchell, 1998; pp. 97-98).

See also Striga angustifolia.

Habitat/ecology:  "The weed frequents light soils, but it will grow well and produce seeds on soils ranging from coarse sands to heavy clays; and infestations are found on peat and muck as well.  The parasite cannot succeed in wet, high rainfall areas" (Holm et al., 1977; p. 458).  "Grassland and cultivated crops on wide range of soil types. Does not grow in wet conditions. Infests a wide range of grass crops (maize, millet, rice, sorghum, sugarcane) and some broadleaf crops (e.g. sunflower, tomatoes, some legumes)." (Waterhouse & Mitchell, 1998; pp. 97-98).

Propagation:  "Immense numbers of tiny dust-like seeds dispersed by wind, water and as a contaminant of farm implements and grain" (Smith, 2002; p. 97).

Native range:  Asia (Waterhouse & Mitchell, 1998; pp. 97-98).

Presence:

Pacific
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
Palau Palau (main island group)	Babeldaob Island	introduced invasive	Space, James C./Lorence, David H./LaRosa, Anne Marie (2009) (p. 5) At the Badrulchau overlook on the north extension of the Compact Road. Voucher: Lorence 9895 (PTBG, BNM, NY, US)
Palau Palau (main island group)	Babeldaob Island		National Tropical Botanical Garden (U.S.A. Hawaii. Kalaheo.) (2008) (voucher ID: PTBG 188) Taxon name on voucher: Striga asiatica (L.) Kuntze
Palau Palau (main island group)	Koror Island	introduced invasive	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1979) (p. 251) As Striga lutea Lour.
Papua New Guinea Papua New Guinea (eastern New Guinea Island)	Papua New Guinea (eastern New Guinea Island)		Holm, Leroy G./Plucknett, D. L./Pancho, J. V./Herberger, J. P. (1977) (p. 459)
Philippines Philippine Islands	Philippine Islands	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
Philippines Philippine Islands	Philippine Islands	native	Merrill, Elmer D. (1923) (pp. 442-443) In open grasslands, parasitic on grass roots, chiefly at medium altitudes.

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	Holm, Leroy G./Plucknett, D. L./Pancho, J. V./Herberger, J. P. (1977) (p. 459)
Cambodia Cambodia	Cambodia (Kingdom of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
China China	China (People's Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
China China	Hong Kong	native	Wu, Te-lin (2001) (p. 248) On grassland.
Indonesia Indonesia	Indonesia (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
Japan Japan	Japan (country)		Holm, Leroy G./Plucknett, D. L./Pancho, J. V./Herberger, J. P. (1977) (p. 459)
Malaysia Malaysia	Malaysia (country of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
Singapore Singapore	Singapore (Republic of)		Waterhouse, B. M./Mitchell, A. A. (1998) (p. 98)
Singapore Singapore	Singapore (Republic of)	uncertain if introduced invasive	Chong, Kwek Yan/Tan, Hugh T. W./Corlett, Richard T. (2009) (p. 82) Weed of uncertain origin
Thailand Thailand	Thailand (Kingdom of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
Vietnam Vietnam	Vietnam (Socialist Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)

Indian Ocean
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
British Indian Ocean Territory Chagos Archipelago	Diego Garcia Island		Stoddart, D. R./Taylor, J. D., eds. (1971) (p. 158) Voucher cited: Stoddart 784 (K, US)
British Indian Ocean Territory Chagos Archipelago	Diego Garcia Island	introduced invasive	Whistler, W. Arthur (1996) (p. 29)
British Indian Ocean Territory Chagos Archipelago	Diego Garcia Island		National Tropical Botanical Garden (U.S.A. Hawaii. Kalaheo.) (1995) (voucher ID: PTBG 23861) Taxon name on voucher: Striga asiatica
La Réunion (France) La Réunion Island	La Réunion Island	introduced invasive	MacDonald, I. A. W./Thebaud, C./Strahm, W. A./Strasberg, D. (1991) (pp. 51-61)
Mauritius Mautitius Islands (Mauritius and Rodrigues)	Mauritius Island	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
Seychelles Seychelles Islands	Agalega Island	native	Fosberg, F. R./Sachet, Marie-Hélène/Stoddart, D. R. (1983) (p. 137) Vouchers cited: Procter 4183, Stoddart 7229 (US), Stoddart 7284 (US)
Seychelles Seychelles Islands	Alphonse Island		Robertson, I. A. D./Robertson, S. A./Fosberg, F. R. (1983) (p. 183) Voucher cited: Robertson 2859 (K)
Seychelles Seychelles Islands	Coetivy Island		Robertson, S. A./Fosberg, F. R. (1983) (p. 155) Voucher cited: Robertson 3062 (K)
Seychelles Seychelles Islands	D'Arros Island		Stoddart, D. R./Coe, M. J./Fosberg, F. R. (1979) (p. 25) Vouchers cited: Gwynne & Wood 939 (EA), Stoddart 7217 (US)
Seychelles Seychelles Islands	Frégate Island		Robertson, S. A./Todd, D. M. (1983) (p. 60) Vouchers cited: Procter 4163, Robertson 2733
Seychelles Seychelles Islands	Platte Island		Robertson, S. A./Fosberg, F. R. (1983) (p. 163) Voucher cited: Robertson 3031 (K)
Seychelles Seychelles Islands	Poivre Island		Robertson, S. A./Fosberg, F. R. (1983) (p. 174) Voucher cited: Robertson 2348 (K)
Seychelles Seychelles Islands	St. Joseph Island		Stoddart, D. R./Coe, M. J./Fosberg, F. R. (1979) (p. 47) Vouchers cited: Gwynne & Wood 969 (EA), Stoddart 7156 (US)

Comments:  "A serious weed in India, South Africa, USA. A principal weed in Mauritius, Zimbabwe, Uganda, Pakistan and Zambia. Heavy infestation can cause complete crop loss" (Waterhouse & Mitchell, 1998; pp. 97-98).

Additional information:
Information from the Global Invasive Species Database.
Species profile from the U.S. Department of Agriculture's National Invasive Species Information Center.

Additional online information about Striga asiatica is available from the Hawaiian Ecosystems at Risk project (HEAR).

Information about Striga asiatica as a weed (worldwide references) may be available from the Global Compendium of Weeds (GCW).

Taxonomic information about Striga asiatica may be available from the Germplasm Resources Information Network (GRIN).

References:

Chong, Kwek Yan/Tan, Hugh T. W./Corlett, Richard T. 2009. A checklist of the total vascular plant flora of Singapore: native, naturalised and cultivated species. Raffles Museum of Biodiversity Research, National University of Singapore. 273 pp.

Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce. 1979. A geographical checklist of the Micronesian dicotyledonae. Micronesica 15:1-295.

Fosberg, F. R./Sachet, Marie-Hélène/Stoddart, D. R. 1983. List of the recorded vascular flora of Agalega. In: Sachet, M. H., D. R. Stoddart, and F. R. Fosberg. Floristics and ecology of Western Indian Ocean islands. Atoll Research Bulletin No. 273. Smithsonian Institution, Washington. 253 pp.

Holm, Leroy G./Plucknett, D. L./Pancho, J. V./Herberger, J. P. 1977. The world’s worst weeds: distribution and biology. East-West Center/University Press of Hawaii. 609 pp.

MacDonald, I. A. W./Thebaud, C./Strahm, W. A./Strasberg, D. 1991. Effects of alien plant invasions on native vegetation remnants on La Reunion (Mascarenes Islands, Indian Ocean). Environmental Conservation 18 (1):51-61.

Merrill, Elmer D. 1923. An enumeration of Philippine flowering plants, vol. 3 [reprint]. Bureau of Printing, Manila. 628 pp.

National Tropical Botanical Garden (U.S.A. Hawaii. Kalaheo.). 2008. Voucher specimen #PTBG188(David H. Lorence 9895).

Robertson, I. A. D./Robertson, S. A./Fosberg, F. R. 1983. List of plants collected on Alphonse Island, Amirantes. In: Sachet, M. H., D. R. Stoddart, and F. R. Fosberg. Floristics and ecology of Western Indian Ocean islands. Atoll Research Bulletin No. 273. Smithsonian Institution, Washington. 253 pp.

Robertson, S. A./Fosberg, F. R. 1983. List of plants collected on Coetivy Island, Seychelles. In: Sachet, M. H., D. R. Stoddart, and F. R. Fosberg. Floristics and ecology of Western Indian Ocean islands. Atoll Research Bulletin No. 273. Smithsonian Institution, Washington. 253 pp.

Robertson, S. A./Fosberg, F. R. 1983. List of plants collected on Platte Island, Seychelles. In: Sachet, M. H., D. R. Stoddart, and F. R. Fosberg. Floristics and ecology of Western Indian Ocean islands. Atoll Research Bulletin No. 273. Smithsonian Institution, Washington. 253 pp.

Robertson, S. A./Fosberg, F. R. 1983. List of plants of Poivre Island, Seychelles. In: Sachet, M. H., D. R. Stoddart, and F. R. Fosberg. Floristics and ecology of Western Indian Ocean islands. Atoll Research Bulletin No. 273. Smithsonian Institution, Washington. 253 pp.

Robertson, S. A./Todd, D. M. 1983. Vegetation of Frégate Island, Seychelles. In: Sachet, M. H., D. R. Stoddart, and F. R. Fosberg. Floristics and ecology of Western Indian Ocean islands. Atoll Research Bulletin No. 273. Smithsonian Institution, Washington. 253 pp.

Space, James C./Lorence, David H./LaRosa, Anne Marie. 2009. Report to the Republic of Palau: 2008 update on Invasive Plant Species. USDA Forest Service, Hilo, Hawai‘i. 227 pp.

Stoddart, D. R./Coe, M. J./Fosberg, F. R. 1979. D'Arros and St. Joseph, Amirante Islands. Atoll Research Bulletin No. 223. The Smithsonian Institution, Washington, D.C. 48 pp.

Stoddart, D. R./Taylor, J. D., eds. 1971. Geography and ecology of Diego Garcia Atoll, Chagos Archipelago. Atoll Research Bulletin No. 149. Smithsonian Institution, Washington. 237 pp.

Thaman, R. R. 1999. Wedelia trilobata: Daisy invader of the Pacific Islands. IAS Technical Report 99/2. Institute of Applied Science, University of the South Pacific, Suva, Fiji. 12 pp.

U.S. Dept. Agr., Agr. Res. Serv. 2011. National Genetic Resources Program. Germplasm Resources Information Network (GRIN). Online searchable database.

U.S. Dept. Agr., Nat. Res. Cons. Serv. 2011. The PLANTS Database. National Plant Data Center, Baton Rouge, LA 70874-4490 USA.

Waterhouse, B. M./Mitchell, A. A. 1998. Northern Australia Quarantine Strategy: weeds target list. Second edition. Australian Quarantine & Inspection Service, Miscellaneous Publication No. 6/98. 110 pp.

Whistler, W. Arthur. 1996. Botanical survey of Diego Garcia, Chagos Archipelago, British Indian Ocean Territory. Isle Botanica. 49 pp.

Wu, Te-lin. 2001. Check List of Hong Kong Plants. Hong Kong Herbarium and the South China Institute of Botany. Agriculture, Fisheries and Conservation Department Bulletin 1 (revised). 384 pp.

Zhengyi, Wu/Raven, Peter H./Deyuan, Hong. 2011. Flora of China (online resource).