Paspalum dilatatum Poir., Poaceae

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Present on Pacific Islands?  yes

Primarily a threat at high elevations?  no

Risk assessment results: 

Reject, score: 9 (Go to the risk assessment (Australia))
High risk, score: 12 (Go to the risk assessment (Pacific))

Common name(s): [more details]

Chinese: mao hua que bai

English: Leichardt grass, caterpillar grass, dallis grass, golden crown grass, paspalum, water grass, water paspalum

French: herbe codaya, herbe de dallis, herbe de miel, herbe sirop, millet bâtard, paspalum, paspalum dilaté

Japanese: shimasuzumenohie

Niuean: hiku nua

Spanish: camalote, chepica gigante, grama de agua, gramilla, pasto dallis, pasto miel, zacate dilación

Habit:  grass

Description:  "Tufted perennials [grass] to 180 cm tall, mostly less; culms mostly erect; glabrous; sheaths compressed, lower ones pubescent basally, upper ones glabrous; ligules to 3-4 mm long, membranous; blades 6-25 (rarely to 35) cm long, (3-) 5-15 mm wide; flat, pubescent at base, margins slightly scabrous; racemes usually 3-5, nodding, 4-10 cm long; rachises narrowly winged, 1-1.2 mm wide; spikelets paired, 3-4 mm long, green or purplish, plano-convex, ovate, acute; glume and sterile lemma alike, 5-9-nerved, apiculate, margins ciliate, obscurely pubescent on the back; fertile lemma 2.5 x 2 mm, indurated; caryopsis 2 mm long, reddish-brown, elliptic" (Stone, 1970; pp. 216-217).

Description from GrassBase.

Habitat/ecology:  "Grass- and heathland, forests, freshwater wetlands, riparian habitats.  A native of moist grassland, this species grows best in moist soils of high fertility.  The dense growth habit smothers all ground flora and prevents recruitment of native shrubs and trees.  Established plants are drought tolerant and tolerate heavy grazing"  (Weber, 2003; p. 304).  "Occasional to locally common on roadsides and sometimes in croplands, but it is not a major pest of crops" (Whistler, 1983; p. 92). "The species prefers wet situations but on low ground may extend from rather dry prairies to marshy meadows.  The plant succeeds on light soils or heavy clay soils and is drought-resistant and frost-sensitive"  (Holm et al., 1977; p. 358).

In New Caledonia, "répandu et apprécié comme espèce fourragère; commun aussi spontané" (MacKee, 1994; p. 60).

Propagation:  "It produces large quantities of seeds which are dispersed by water and animals  (Weber, 2003; p. 304).

Native range:  Tropical America but widely introduced as a forage species.

Presence:

Pacific
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
American Samoa Tutuila Islands	Tutuila Island	introduced invasive	Space, James C./Flynn, Tim (2000) (p. 37)
Australia (Pacific offshore islands) Lord Howe Island	Lord Howe Island	introduced	Pickard, J. (1984) (p. 205)
Australia (Pacific offshore islands) Lord Howe Island	Lord Howe Island	introduced invasive cultivated	Orchard, Anthony E., ed. (1994) (p. 22) "Introduced as a pasture grass and now common, with a tendency to weediness". Vouchers cited: P.S. Green 2036 (K), L.M. Bingley 5(K), R.D. Hoogland 8752 (CANB)
Australia (Pacific offshore islands) Norfolk Islands	Norfolk Island	introduced invasive cultivated	Orchard, Anthony E., ed. (1994) (p. 12) "Introduced as a pasture grass and now common, with a tendency to weediness". Vouchers cited: P.S. Green 1479 (A), M. Lazarides 8052 (CANB), W.R. Sykes NI 444 (CHR)
Cook Islands Southern Cook Islands	Mangaia Island		National Tropical Botanical Garden (U.S.A. Hawaii. Kalaheo.) (2002) (voucher ID: PTBG 346) Taxon name on voucher: Paspalum dilatatum
Cook Islands Southern Cook Islands	Ma‘uke Island		McCormack, Gerald (2013)
Cook Islands Southern Cook Islands	Miti‘aro Island		McCormack, Gerald (2013)
Cook Islands Southern Cook Islands	Rarotonga Island		Sykes, Bill (year unknown)
Fiji Fiji Islands	Kandavu Island	introduced invasive	Smith, Albert C. (1979) (pp. 337-338) Vouchers cited: DA 9059, DA 2989
Fiji Fiji Islands	Rambi Island	introduced invasive	Smith, Albert C. (1979) (pp. 337-338) Voucher cited: DA 5743
Fiji Fiji Islands	Taveuni Island	introduced invasive	Smith, Albert C. (1979) (pp. 337-338) Voucher cited: DA 8918
Fiji Fiji Islands	Vanua Levu Island	introduced invasive	Smith, Albert C. (1979) (pp. 337-338) Voucher cited: DA 8730
Fiji Fiji Islands	Viti Levu Island	introduced invasive	Smith, Albert C. (1979) (pp. 337-338) Vouchers cited: Greenwood Mar. 1921, DA 11841, DA 7839, DA 7891, Gillespie 3606, DA 3967, DA 7965, DA 7507, DA 7387, DA 8026, DA 1672, DA 7690, DA 7484
French Polynesia Marquesas Islands	Nuku Hiva (Nukahiva) Island	introduced invasive abo. intro.	Lorence, David H./Wagner, Warren L. (2013)
French Polynesia Marquesas Islands	Nuku Hiva (Nukahiva) Island		National Tropical Botanical Garden (U.S.A. Hawaii. Kalaheo.) (2004) (voucher ID: PTBG 42444) Taxon name on voucher: Paspalum dilatatum
French Polynesia Society Islands	Raiatea (Havai) Island		National Tropical Botanical Garden (U.S.A. Hawaii. Kalaheo.) (1981) (voucher ID: PTBG 38276) Taxon name on voucher: Paspalum dilatatum Poir.
French Polynesia Society Islands	Tahiti Island		Fosberg, F. R. (1997) (p. 104)
French Polynesia Society Islands	Tahiti Island	introduced cultivated	Florence, J./Chevillotte, H./Ollier, C./Meyer, J.-Y. (2013) Cultivée
French Polynesia Society Islands	Tupai Island	native	Fosberg, F. R. (1997) (p. 104)
Guam Guam Island	Guam Island	introduced cultivated	Stone, Benjamin C. (1970) (pp. 216-217) Voucher cited: Stone 4080 (GUAM), Stone 4716 (GUAM), MacGregor 516
Guam Guam Island	Guam Island	introduced	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1987) (p. 54)
State of Hawaii Hawaiian Islands	Hawai‘i (Big) Island	introduced invasive	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 1576) Voucher cited: Forbes 205.H (BISH)
State of Hawaii Hawaiian Islands	Kaua‘i Island	introduced invasive	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 1576)
State of Hawaii Hawaiian Islands	Lāna‘i Island	introduced invasive	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 1576)
State of Hawaii Hawaiian Islands	Maui Island	introduced invasive	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 1576)
State of Hawaii Hawaiian Islands	Moloka‘i Island	introduced invasive	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 1576)
State of Hawaii Hawaiian Islands	O‘ahu Island	introduced invasive	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 1576)
Japan (offshore islands) Ogasawara (Bonin) Islands	Bonin (Ogasawara) Islands	introduced	Kato, Hidetoshi (2007)
New Caledonia Îles Loyauté (Loyalte Islands)	Îles Loyauté (Loyalty Islands)	introduced invasive	Tassin, Jacques (2005)
New Caledonia Îles Loyauté (Loyalte Islands)	Îles Loyauté (Loyalty Islands)	introduced invasive cultivated	MacKee, H. S. (1994) (pp. 60-61)
New Caledonia New Caledonia	New Caledonia Islands		Swarbrick, John T. (1997) (p. 95)
New Caledonia New Caledonia Archipelago	Île Grande Terre	introduced invasive	Tassin, Jacques (2005)
New Caledonia New Caledonia Archipelago	Île Grande Terre	introduced invasive cultivated	MacKee, H. S. (1994) (pp. 60-61) Voucher cited: Franc 2190
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 cultivated	MacKee, H. S. (1994) (pp. 60-61)
New Zealand (offshore islands) Kermadec Islands	Kermadec Islands	introduced invasive	Edgar, E./Connor, H. (2000) (p. 556) "Shingly roadsides, waste land, ditch banks, pasture, consolidated sand dunes".
New Zealand (offshore islands) Kermadec Islands	Raoul Island	introduced invasive	Sykes, W. R. (1977) (pp. 173-174)
Niue Niue	Niue Island		Sykes, W. R. (1970) (p. 248) Voucher cited: CHR 168806
Niue Niue	Niue Island	introduced invasive	Whistler, W. A. (1988) (p. 54)
Niue Niue	Niue Island	introduced invasive	Yuncker, T. G. (1943) (p. 22) Vouchers cited: Yuncker 9721 (BISH), Yuncker 9868 (BISH) "Occasional in waste areas".
Niue Niue	Niue Island	introduced invasive	Space, James C./Waterhouse, Barbara M./Newfield, Melanie/Bull, Cate (2004) (p. 45)
Papua New Guinea Papua New Guinea (eastern New Guinea Island)	Papua New Guinea (eastern New Guinea Island)		Waterhouse, D. F. (1997) (p. 64)
Philippines Philippine Islands	Philippine Islands	introduced invasive	Holm, Leroy G./Plucknett, D. L./Pancho, J. V./Herberger, J. P. (1977) (pp. 358-361)
Samoa Western Samoa Islands	Upolu Island		Whistler, W. A. (1988) (p. 54)
Solomon Islands Solomon Islands	Solomon Islands		Swarbrick, John T. (1997) (p. 95)
Solomon Islands Solomon Islands	Solomon Islands	introduced invasive	Hancock, I. R./Henderson, C. P. (1988) (p. 97)
Tonga Tongatapu Group	Tongatapu Island		Whistler, W. A. (1992) (p. 101) Voucher cited: Soakai 181
Tonga Tongatapu Group	Tongatapu Island		Yuncker, T. G. (1959) (pp. 58-59) Vouchers cited: Hürlimann 305, Yuncker 15160
United States (other Pacific offshore islands) Johnston Atoll	Johnston Island	introduced invasive	Amerson, A. Binion, Jr./Shelton, Philip C. (1976) (p. 53)
Vanuatu New Hebrides Islands	Vanuatu (Republic of)		Swarbrick, John T. (1997) (p. 95)

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. 361)
China China	China (People's Republic of)		Hafliger, Ernst/Scholz, Hildemar (1980) (p. 96)
China China	Hong Kong	introduced cultivated	Wu, Te-lin (2001) (p. 342) On grasslands.
Indonesia Indonesia	Indonesia (Republic of)	introduced invasive	Holm, Leroy G./Plucknett, D. L./Pancho, J. V./Herberger, J. P. (1977) (pp. 358-361)
Japan Japan	Japan	introduced invasive	Holm, Leroy G./Plucknett, D. L./Pancho, J. V./Herberger, J. P. (1977) (pp. 358-361)
Japan Japan	Japan	introduced	Mito, Toshikazu/Uesugi, Tetsuro (2004) (p. 192)
Malaysia Malaysia	Malaysia (country of)	introduced invasive	Holm, Leroy G./Plucknett, D. L./Pancho, J. V./Herberger, J. P. (1977) (pp. 358-361)
Mexico Mexico	Mexico (United Mexican States)		Hafliger, Ernst/Scholz, Hildemar (1980) (p. 96)
New Zealand New Zealand	New Zealand (country)	introduced invasive	Edgar, E./Connor, H. (2000) (p. 566) "Shingly roadsides, waste land, ditch banks, pasture, consolidated sand dunes".
South America (Pacific rim) South America (Pacific rim)	Chile (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
South America (Pacific rim) South America (Pacific rim)	Colombia		Holm, Leroy G./Plucknett, D. L./Pancho, J. V./Herberger, J. P. (1977) (p. 361)
Taiwan Taiwan Island	Taiwan Island	introduced invasive	Holm, Leroy G./Plucknett, D. L./Pancho, J. V./Herberger, J. P. (1977) (pp. 358-361)
Vietnam Vietnam	Vietnam (Socialist Republic of)	introduced invasive	Holm, Leroy G./Plucknett, D. L./Pancho, J. V./Herberger, J. P. (1977) (pp. 358-361)

Indian Ocean
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
Mascarene Islands Mascarene Islands (Mauritius, La Reunion, Rodrigues)	Mascarene Islands	introduced	Weber, Ewald (2003) (p. 304)
Mauritius Mautitius Islands (Mauritius and Rodrigues)	Mauritius Island		Holm, Leroy/Pancho, Juan V./Herberger, James P./Plucknett, Donald L. (1979) (p. 267)

Comments:  A problem species in Hawai‘i and New Zealand.

Control: 

Physical:  "Small plants can be dug out, rhizomes must be removed to prevent regrowth.  Plants regenerate rapidly after cutting, so mowing is best combined with chemical control".

Chemical:  "An effective herbicide for young plants is paraquat, mature plants are best sprayed with glyphosate"  (Weber, 2003; p. 304).