Latin name

Cyperus haspan L.

Family

Cyperaceae

Common name(s)

Sedge

Synonym(s)

Cyperus halpan L.

Geographical distribution

Asia: China (including Hong Kong and Taiwan), Korea, and Japan.

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

Rest of the world: Argentina, Benin, Botswana, Brazil, Congo, Fiji, Ghana, Honduras, Peru, Senegal, Sudan, Suriname, United States, West Africa, Zambia, and Zimbabwe.

Morphology

A perennial with short rhizome and reddish roots.

Stem: slender and weak, tufted, smooth and triangular, up to 40—cm—tall.

Leaf: linear, 2—20—cm—long; sheath to 6—cm—long.

Inflorescence: umbel, simple to compound, loose or dense up to 15—cm across; primary rays up to 20; 2—3 unequal involucral bracts, longest to 10—cm.

Biology and ecology

Thrives in open and wet places although it is also found in drier locations.

Propagates by seeds and growth from rhizomes. Produces large quantities of seeds and reported to produce up to 50,000 seeds per plant.

Agricultural importance

Common weed of lowland rice. An alternate host for nematodes such as Criconemella onoensis and Pratylenchus indicus and also for Rhizoctonia solani, which causes rice sheath blight.

Management

Cultural control: can be controlled by hand pulling or hoe.

Chemical control: 2,4-D or MCPA in rice.

Selected references

Galinato MI, Moody K, Piggin CM. 1999. Upland rice weeds of South and Southeast Asia. Los Baños (Philippines): International Rice Research Institute. 156 p.

Holm L, Pancho JV, Herberger JP, Plucknett DL. 1979. A geographical atlas of world weeds. New York (USA): John Wiley & Sons, Inc. 391 p.

Kern JH. 1974. Cyperaceae. Flora Malesiana Ser. 1 7(3): 435-753.

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

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

Contributors

JLA Catindig, RT Lubigan, and DE Johnson