Eleusine indica (L.) Gaertn. ssp. indica

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Graminae

Common names

Crow's foot grass (Australia), goose grass (United States), grama de caballo (Cuba), pate de gallina (Peru), rapoka grass, crab grass (South Africa), Indian goose grass, kavoronaisivi (Fiji), mangrasi (Suriname).

Description

Coarse, caespitose annual, branching at the base, 30-60 cm tall, the culms ascending or prostrate, smooth, compressed; leaf-sheaths smooth, blades linear, flat or folded, 3-8 mm wide. Two to six spikes, digitate, sessile, 4-15 cm long, with usually one inserted lower on the culm, the rachis prominently flattened with the spikelets loosely imbricate and secund. Spikelets sessile with three to 15 flowers, 3-4 mm long. Glumes rather unequal, the lower narrow, oblong, obtuse, one-nerved, the upper lanceolate or ovate-lanceolate, three-nerved, rather acute. Lemmas lanceolate, rather acute, sometimes keeled, 3 mm long. Pericarp persistent, very loose and membranous, enclosing the rugose seed (Gardner, 1952). Distinguished from Chloris and Dactyloctenium by having awnless spikes. It has a particularly tough root system and is hard to pull out. Subspecies africana is a tetraploid, larger, with larger spikelets and a ligule that has a definite ciliate fringe (Chippendall & Crook, 1976). At low densities it can compensate by producing more tillers (Jones & Aliyu, 1976).

Distribution

Tropical and subtropical regions.

Season of growth

Summer.

Altitude range

Sea-level to 2 000 m.

Rainfall requirements

It commonly grows in the 500-1 200 mm rainfall range.

Drought tolerance

Its extensive root system allows it to forage for moisture well during its annual growth.

Tolerance to herbicides

To control this grass use cultivation, but if chemical control is needed use a pre-emergent spray of 2,4-D sodium salt at 9.5 kg/ha of an 840 g AI/kg product (e.g. Hormicide). No wetting agent is required when used as a pre-emergent spray. Use a minimum of 340 litres of water per hectare. Seedlings up to the four-leaf stage can be controlled by paraquat at 570 ml of a 200 g AI/litre product (e.g. Gramoxone) per 200 litres of water plus a surfactant at 250 ml/200 litres water. Spray until spray material runs off leaves (Tilley, 1977). In lawns in the United States potassium thiocyanate and disodium methylarsonate are recommended as effective control measures (Ivens, 1967). E. indica was killed in P. maximum and B. decumbens pastures on the Atherton Tableland, Queensland by atrazine above a strength of 0.9 kg AI/ha (Hawton, 1976). Setaria sphacelata seed crops can be selectively rid of E. indica by pre- emergence treatment with methabenzthiazuron at 1-2 kg/ha. S. sphacelata is susceptible to atrazine, simazine and terbutryne (Hawton, personal communication), Jones and Aliyu (1976) had some success with pre-emergent spraying of trifluralin at rates of 0.56 kg/ha AI in Leucaena leucocephala but yield of the legume was affected. Activated charcoal and Dacthal gave some control but more research is needed to clarify the effect.

Seedling vigour

Seedlings have exceptional vigour and quickly establish themselves.

Vigour of growth and growth rhythm

On the Atherton Tableland vigorous growth occurs between 8 September and 16 January at the expense of Setaria sphacelata seed crops (Hawton, 1979).

Suitability for hay and silage

It can be made into coarse hay and silage.

Toxicity

It often contains prussic acid (Cyanogenetic glucoside), the main concentration being in the seeds varying from 0.015 to 0.019 percent, just below the theoretical potential danger level (Everist, 1974).

Cultivars

There are no cultivars registered. Bogdan (1977) records a subspecies africana (Kennedy and O'Byrne), Phillips, a more robust form, a tetraploid with 2n=36, from East Africa occurring at higher altitudes than ssp. indica.

Main attributes

Its aggressiveness and its easy establishment for stabilizing sandy soils.

Main deficiencies

Its problem as a weed, its occasional toxicity.

Optimum temperature for growth

The optimum mean temperature for seed germination was 23°C at Kairi (lat. 17°18'S, altitude 700 m) on the Atherton Tableland, Queensland (Hawton, 1979).G

Minimum temperature for growth

Hawton (1979) found mean temperatures below 23°C restricted germination, but it could occur at temperatures as low as 20°C.

Palatability

It is eaten when young; when older the foliage is very tough.

Natural habitat

Widespread weed of disturbed land.

Genetics and reproduction

2n= 18, 36 (Fedorov, 1974).

Economics

A worldwide weed of the tropics. It is one of the worst weeds of maize in Zimbabwe and South Africa (Ivens, 1967). It is the major weed problem in swards of Panicum maximum, Setaria sphacelata and Brachiaria decumbens grown for seed production on the Atherton Tableland, Queensland (Hawton 1976, 1978) and in the establishment of the browse legume Leucaena leucocephala at Samford, Queensland (Jones & Aliju, 1976). In India the seeds of E. indica are eaten by humans in times of drought.

Animal production

No figures have been cited.