• Latin name
• Family
• Common name(s)
• Synonym(s)
• Geographical distribution
• Morphology
• Biology and ecology
• Agricultural importance
• Management
• Selected references
• Contributors

Monochoria vaginalis

Monochoria vaginalis is a fleshy aquatic herb with ovate or lanceolate leaves and dark blue flowers (IRRI).

Latin name

Monochoria vaginalis (Burm. f.) Presl C. ex Kunth

Family

Pontederiaceae

Common name(s)

Monochoria and pickerel weed

Synonym(s)

Monochoria vaginalis (Burm. f.) Presl C., Pontederia vaginalis Burm. f. (basionym), P. linearis Hassk., P. pauciflora Blume, P. ovata Hook & Arn.

Geographical distribution

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

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 and United States (Hawaii).

Morphology

A hairless, fleshy, erect, annual or perennial herb, 5—50—cm—tall.

Stem: leaf petioles clump in form of rosette.

Leaf: very variable, young, or submerged leaves may be without lamina: older leaves broadly ovate or lanceolate.

Inflorescence: few-to many-flowered raceme; flowers dark blue, up to 1—cm—long with less than 1—cm pedicels. 

Biology and ecology

Aquatic weed in lowland rice fields and swampy areas.

Single plants can produce up to 61,000 seeds and also 4 suckers. Germination requires submerged soil temperature of 28—35º C and germination can be induced by submergence at 1—cm water depth.

Agricultural importance

Monochoria vaginalis is an important weed in lowland rice fields and in taro. In rice, 80 plants per m2 of M. vaginalis can reduce yield of rice by 25%. 

Management

Cultural control: hand weeding is commonly used to control this weed in transplanted lowland rice.

Chemical control: preemergence application of butachlor or postemergence application of 2,4-D. 

Selected references

Backer CA. 1951. Pontederiaceae. Flora Malesiana Ser. 1 4:255 - 261.

Bariuan FV. 1986. Selected studies on biology and competitive efficiency of Monochoria vaginalis. Natl. Crop Prot. Cent. Newsl. 1(3):3-4.

Civico RSA, Moody K. 1979. The effect of the time and depth of submergence on growth and development of some weed species. Philipp. J. Weed Sci. 6:41-49.

Holm L, Plucknett DL, Pancho JV, Herberger JP. 1979. The world's worst weeds: distribution and biology. Honolulu, Hawaii (USA): University Press of Hawaii. 609 p.

Lamid Z. 1981. Biology and response of Monochoria vaginalis (Burm. f.) Presl to selective herbicides at different growth stages. College, Laguna, (Philippines): M.S. thesis. University of the Philippines at Los Baños. 74 p.

Lubigan RT, Vega MR. 1971. The effect of the competition of rice with Echinochloa crus-galli (L.) Beauv. and Monochoria vaginalis (Burm. f. ) Presl. Philipp. Agric. 15: 210-215.

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

Moody K. 1992. Weeds of cropped areas in the Philippines. Philipp. J. Weed Sci. 19:31-78.

Pablico PP, Moody K. 1986. A dry season lowland rice (Oryza sativa) weed survey in Central and Southern Luzon, Philippines. Philipp. J. Weed Sci. 13:39-49.

Pancho JV, Soerjani M.1978. Aquatic weeds of Southeast Asia: a systematic account of common Southeast Asian aquatic weeds. Bogor (Indonesia): SEAMEO Regional Center for Tropical Biology. 130 p.

Contributors

JLA Catindig, RT Lubigan, and DE Johnson