Digitaria eriantha Steudel

 

Home
Photo1.jpg (1333 bytes)

Gramineae

 

Synonyms
  • Digitaria smutsii Stent (1924),
  • Digitaria decumbens Stent (1930),
  • Digitaria pentzii Stent (1930),
  • Digitaria valida Stent (1930),
  • Digitaria pentzii Stent var. stolonifera (Stapf) Henrard (1950);
  • Digitaria eriantha Steudel with 4 subspecies: ssp. eriantha, ssp. pentzii (Stent) P.D.F. Kok (1981), ssp. stolonifera (Stapf) P.D.F. Kok (1981), ssp. transvaalensis P.D.F. Kok (1981).
Author: L.’t Mannetje

Common names

Common finger grass, Smuts finger grass, digit grass (also used for other spp.), pangola or pongola grass (Digitaria decumbens) (En).

Origin and geographic distribution

D. eriantha is a species of subtropical southern Africa. A single clone, commonly referred to as pangola grass, is now widespread in grazing areas throughout the world's humid tropics and subtropics, including South-East Asia, having been extensively planted from the 1960s to the 1980s. Many other lines have been distributed for evaluation.

Description

More or less robust perennial, growing either as a dense tussock, with or without extended stolons or as a continuous stoloniferous sward. Stolon internodes with or
without hairs. Culms erect or ascending, sometimes rooting at the nodes, to 1.5 m tall. Leaf-sheath scabridulous, glabrous to hairy; ligule subtriangular, 2-4 mm long, shortly ciliate; leaf-blade linear, 5-60 cm x 1.5-12 mm, glabrous or hairy, but minutely scaberulous on both surfaces. Inflorescence a racemose panicle, composed of 3-14 erect racemes 6-18 cm long, borne in loose whorls and with some racemes single on an axis up to 7 cm long; spikelets 2-4 mm long, conspicuously hairy; lower glume to 0.5 mm long, the upper as long as the spikelet and appressed hairy; lower lemma minutely hairy, characteristically with 7 smooth rather than scabrous nerves. Many clones are sterile or almost sterile (Hacker 1992). D. eriantha is extremely diverse but it is probable that 80% of agronomic publications are concerned with a single genotype. Performance data should therefore not be generalized for the species as a whole. D. eriantha is closely related to the tropical D. milanjiana from which it may only be distinguished by the absence of scabrosity on nerves of the lower lemma, a characteristic which may be difficult to determine, even with a lens. Frequently in the agronomic literature, accessions are described simply as Digitaria sp., which is of little help when documenting species characteristics. Kok (1984) reduced the four earlier recognized subspecies for the South African taxa, to synonyms of the whole species complex. Two seed-producing cultivars, 'Premier' and 'Advance', belonging to D. eriantha ssp. eriantha (in the sense of Kok), have recently been released in Australia. Pangola grass belongs to D. eriantha ssp. pentzii (in the sense of Kok), and cultivars 'Taiwan', 'Transvala' and 'Slenderstem' have been developed in the United States from southern African introductions of this subspecies.

Use

It is utilized extensively as a grass for grazing, hay or silage (Meeske et al. 1999) making, mostly with N fertilization rather than a companion legume.

Properties

D. eriantha is often considered to be one of the higher quality tropical grasses. Pangola grass has an N concentration of (0.5-)1.5-2.0(-4.0)%. Phosphorus concentration can be too low for livestock on low-P soils in the absence of P fertilizer. Dry matter digestibility varies between 45-70%. Pangola grass has relatively high concentrations of Na in its tissues, compared with many other tropical grasses.

Toxicity

None has been reported.

Ecology

Accessions of ssp. pentzii (in the sense of Kok) (pangola, 'Slenderstem') are recommended in Malaysia and the Philippines for poorly drained soils. They are tolerant of flooding, and any areas where the grass dies out are rapidly re-invaded by stolons from the surrounding sward. Pangola grass is intolerant of shade and is therefore not suitable for integrating with plantation agriculture. Seed producing cultivars 'Premier' and 'Advance' are adapted to sub-humid subtropical conditions and they have markedly better cool-season growth than other cultivars. In subtropical areas, pangola grass flowers in mid-summer; flowering time differs with other genotypes, with cultivar 'Premier' (ssp. eriantha in the sense of Kok) flowering in late spring and again in autumn (Hacker 1992).

Soil requirements

Pangola grass can grow on a wide range of soil types from sands to heavy clays. However, the seed-producing lines tend to be better adapted to sandy loam soils as seedling establishment can be difficult on heavier soils, but, once satisfactorily established, they also grow vigorously on clays.

Propagation and planting

Stoloniferous genotypes are planted vegetatively. Actively growing swards are allowed to become stemmy and are then cut and the material spread on a cultivated surface at 0.5-2 t of green matter per hectare. This is then disked in, or trampled in by cattle if the ground is too wet for implements. Seed-producing cultivars such as 'Premier' and 'Advance' require a reasonable seed-bed for establishment and an absence of serious competition in the early stages. Once established, however, they have the capacity to thicken up and spread from the sown area (Hacker 1992).

Growth and development

In warm moist environments vegetatively planted swards establish rapidly and in general weeds are suppressed. Stoloniferous cultivars can become sodbound and may benefit from periodic renovation by disking.

Diseases and pests

Susceptibility to the rust Puccinia oahuensis, a widespread disease occurring in the Americas and Australia, varies between genotypes, with 'Transvala' showing some resistance. The most serious disease of D. eriantha is pangola stunt virus, a dwarfing disease which has seriously reduced the usefulness of pangola since it was first reported in Surinam in 1960. The disease is transmitted by an aphid, Sogatella furcifera, or in Australia by the related S. kolophon. 'Transvala' has some resistance to this disease but trials in Australia on a number of lines of digit grasses failed to show any resistance. Insects which cause damage include spittlebugs (Tomaspis flavopicta, T. humeralis, Prosapia bicincta) in Brazil and Taiwan, Rhodes grass mealy bug (Antonina graminis) (also in Brazil and Taiwan), chinch bug (Blissus leucopterus) in Taiwan, sugar-cane aphid (Sipha flava) in the Caribbean region and Taiwan, army worms (Laphigma spp., Spodoptera spp. and Mocis spp.), and the root-knot nematodes Belonolaimus longicaudatus and Platylenchus brachyurus in the Americas (Hacker 1992). Pangola grass is infected by smut fungi in South Africa (Vanky 1999).

Performance

D. eriantha is an aggressive species and does not generally combine well with pasture legumes. Herbage DM yields as high as 36 t/ha per year have been reported, but production is more normally in the range 11-22 t/ha per year. Once established, D. eriantha tolerates heavy stocking rates. Beef production from N fertilized pangola can exceed 1000 kg/ha per year. Grown with tropical legumes, 'Transvala' digit grass produced an average liveweight gain of 350 kg/ha under continuous grazing at a stocking rate of 2.6 steers/ha in Malaysia. From ssp. eriantha (in the sense of Kok) in South Africa, beef production ranged from 84-110 kg/head per season at a stocking rate of 7.5 animals per hectare. Milk yields of 6000 kg/ha per year have been obtained from well-fertilized pangola grass pastures (Hacker 1992). Seed production by fertile genotypes averages about 190 kg/ha (Ramirez and Hacker 1996).

Links

References

Hacker J.B. (1992); Kok P.D.F. (1984); Meeske R. et al. (1999); Ramirez L. and Hacker J.B. (1996); Vanky K.(1999)