Ageratum conyzoides L. - ASTERACEAE - Dicotyledon

Common name : tropical ageratum.

Botany Biology Phenology Ecology Distribution Agricultural importance Cultural control Chemical control

Botany :

Description :

Terrestrial, annual, erect herb, up to 120 cm tall. Taproot white or brown. Stem rounded, solid, hairy. Stipules absent. Leaves simple, not divided or lobed, opposite, stalked, ovate, hairy or not on both sides, margin coarsely dentate, apex acute, base rounded or truncate, pinnately veined. Flowers bisexual, grouped together in a terminal head, consisting of tubular flowers only, sessile, white or blue, petals 5. Fruit an achene, pappus present.

Biology :

Reproduction by seeds. Seeds are dispersed by wind and water.

Phenology :

Flowering all the year round and may produce up to 40 000 seeds per plant.

Ecology :

Moister areas in agricultural land, waste places, compounds, roadsides, plantations of all kinds; up to 3000 m alt. Upland rice fields.

Distribution :

Tropical Africa, Indian continent, S.E.Asia, Malesia, naturalized in tropical America.

Agricultural importance :

May become troublesome in plantations after grasses have been suppressed.

Cultural control :

Ageratum conyzoides can be readily controlled when young by hand pulling or hoeing.

Chemical control :

Seedlings and young stages readily controlled by 2,4-D, MCPA and other growth regulators that are used on cereal crops.

Uses :
This species is sometime used as a medicinal plant.

References :
- Marita I.G., Keith Moody, Colin M. Piggin. 1999. Upland Rice Weeds of Southeast Asia, IRRI.
- Soerjani M., Kostermans A. J. G. H., Tjitrosoepomo G. 1987. Weeds of rice in Indonesia. Balai Pustaka. Jakarta.

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