Fimbristylis miliacea (L.) Vahl - CYPERACEAE - Monocotyledon

Basionym : Scirpus miliaceus L.

Common name : grass-like fimbristylis, lesser frimbrstylis, hoorah grass.

Botany Biology Phenology Distribution Agricultural importance Cultural control Biological control Chemical control

Botany :

Description :

Terrestrial, annual or perennial, tufted herb. Roots fibrous, white or brown. Stems erect, flat, solid, glabrous. The stem transversal section is four or five-angled and somewhat flattened. Stipules absent. Leaves simple, not lobed or divided, sessile, linear, more than 2 cm long/wide, margin entire, apex acute, base clasping. Leaf sheath present, rounded or compressed in cross section. Flowers bisexual, grouped together in a terminal umbel, sessile, green or brown, petals absent. Fruit a nut.

Biology :

F. miliacea is very competitive in rice. Because it is a prolific seed producer, it soon becomes widespread when it enters new area of rice production.
A very important work on the biology of this species was done in Japan during sixties; we summarize some results of their studies. This species has the unique ability to keep seedlings emerging in the field throughout the entire culture period. This accounts in part for its increasing importance as the use of herbicides become more widespread. A single treatment will affect only the crop of seedlings present at the time, and the many plants which appear later can escape the herbicide. This permits both competition and seed production. As other species are removed with herbicides, F. miliacea can compete more effectively.
F. miliacea had many more seedlings than did any other weed emerging in the driest soil. There were twice as many seedlings coming up from the the dry soil as from the submerged soil and this was true in both the early and and usual planting seasons.
F. miliacea is eaten by cattle, the seeds passing through their digestive tracts mostly undigested and germinating near droppings.
Studies of the growth of root systems in rice fields in India have shown that roots of F. miliacea spread much more rapidly than do the roots of rice. The roots of the weed spread vigorously in all directions, growing between the rice roots and eventually surrounding them and competing seriously with them for nutrients.

Phenology :

Flowering and fruiting throughout the year.

Distribution :

Pantropical, originating from tropical America.

Agricultural importance :

It is one of the most harmful weeds in rice fields. It increases with the advent of herbicides.

Cultural control :

Keeping a layer of water (15cm) on rice in Surinam is said to suppress germination of F. miliacea completely.

Biological control :

Very little is known about natural enemies of this sedge; the fungi, Corticum sasaki , and the nematode Meloidogyne graminicola, may be considered for biological control.

Chemical control :

Pre-emergence application of Pretilachlor 1.0 kg/ha or Post-emergence application of 2_4-D at 500 /ha or Almix at 4 g/ha.

References :
-Holm L. G., Plucknett D. L., Pancho J. V., Herberger J. P. 1991. The world’s worst weeds. Distribution and Biology. East-West Center by the University Press. Hawaii.
-Waterhouse D. F. 1994. Biological control of weeds: Southeast Asian prospects. ACIAR Monograph No. 26, 302pp.

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