Latin name

Leersia hexandra Sw.

Family

Poaceaea

Common name(s)

Southern cutgrass, clubhead cutgrass, rice grass, tiger's tongue grass, and swamp rice grass

Synonym(s)

Leersia abyssinica Hochst. ex A. Rich., L. capensis Müll. Hal., L. luzonensis J. Presl, L. mexicana Kunth., L. mexicana (Kunth) Döll, Oryza hexandra (Sw.) Döll, Homalocenchrus hexandra (Sw.) Kuntze

Geographical distribution

Asia: China.

South and Southeast Asia: Bangladesh, Brunei, Cambodia, India, Indonesia, Lao PDR, Malaysia, Myanmar, Nepal, Pakistan, Philippines, Sri Lanka, Thailand, and Vietnam.

Rest of the world: Australia, Bolivia, Colombia, Costa Rica, Ecuador, El Salvador, Guatemala, Madagascar, Mexico, Nicaragua, Nigeria, Papua New Guinea, Paraguay, Peru, Tanzania, Uganda, United States, Venezuela, West Africa, Zambia, and Zimbabwe.

Morphology

A slender, creeping or ascending, tufted, aquatic or swampy perennial grass up to 50—cm—long.

Stem: ascending branched, rooting at base; as long as 50—100—cm; nodes swollen and collar of white hairs; long rhizomes forming a dense mat.

Leaf: thin, rather rough, linear lanceolate, 15—30—cm—long; back of the midrib has pointed spines; ligule long, round, thin, rather stiff, and hairy.

Inflorescence: an open terminal panicle, 5—15—cm—long; short spiny bristles are visible along the margins of the spikelets; spkelets 3—4.5—mm—long.

Biology and ecology

Leersia hexandra prefers wetlands, drains, and shallow water channels. Propagates by rhizomes and seeds, and by division of rootstocks. Flowering occurs throughout the year, but each plant flowers only once.

Agricultural importance

Can be a difficult weed to manage: spines on leaves can cut skin while hand weeding and perennial nature may necessitate repeated control measures.

Leersia hexandra is host to several pests of economic importance. It can harbor insect pests such as Dicladispa armigera (Olivier), Nephotettix spp., Nilaparvata lugens, (Stål), Orseolia oryzae (Wood-Mason), and Sogatella furcifera (Horvath), and diseases such as Magnaporthe sp., Xanthomonas sp., Cochliobolus sp., rice grassy stunt, tungro, and rice yellow dwarf, and nematodes such as Ditylenchus sp.

Management

Cultural control: rotovating and puddling rice fields under inundated or dry conditions.

Chemical control: Glyphosate applied before land preparation.

Selected references

Hafliger E, Scholz H. 1981. Grass weeds 2. Basle (Switzerland): CIBA-GEIGY Ltd. 137 p.

Holm LG, Plucknett DL, Pancho JV, Herberger JP. 1977. The world's worst weeds: distribution and biology. Honolulu, Hawaii (USA): University of Hawaii Press. 609 p.

Hsu C. 1978. Gramineae (Poaceae). Flora of Taiwan. 5:373-783.

Moody K. 1981. Major weeds of rice in South and Southeast Asia. Manila (Philippines): International Rice Research Institute. 79 p.

Moody K. 1989. Weeds reported in rice in South and Southeast Asia. Manila (Philippines): International Rice Research Institute. 442 p.

Moody K, Munroe CE, Lubigan RT, Paller Jr. EC. 1984. Major weeds of the Philippines. Weed Science Society of the Philippines. College, Laguna (Philippines): University of the Philippines at Los Baños. 328 p.

Pancho JV, Obien SR. 1995. Manual of ricefield weeds in the Philippines. Muñoz, Nueva Ecija (Philippines): Philippine Rice Research Institute. 543 p.

Soerjani M, Kostermans AJGH, Tjitrosoepomo G. 1987. Weeds of rice in Indonesia. Jakarta (Indonesia): Balai Pustaka. 716 p.

Contributors

JLA Catindig, RT Lubigan, and DE Johnson