Digitaria sanguinalis
(large crabgrass)

Annual
Grass / sedge
Herbaceous
Seed propagated

Originally native to Europe, D. sanguinalis is now found throughout temperate and warm regions of the world, though with a more temperate distribution than D. ciliaris.

D. sanguinalis is a noxious weed particularly common in maize, beet, vegetable crops, orchards and vineyards. It is found on sands and wet loams in warmer places (Behrendt and Hanf, 1979) and is one of the major weeds found in early-sown rice (Choi et al., 1998). It is also found on waste ground, railway embankments, neglected lawns and grassy ridges. Kwon et al. (1996) noted that in gladiolus, D. sanguinalis was the dominant weed, particularly in the late stages of gladiolus growth.

D. sanguinalis is an annual, late spring-and summer-germinating plant. Tillering initiates after emergence of the fourth leaf. Mature plants cover extensive areas developing a 'mulch' or 'tuft' 40-60 cm deep (Kissman and Groth, 1993).

One isolated plant can bear more than 150,000 'seeds' (caryopses). Seeds are dormant when shed. Seedling emergence can occur from 6 cm depth in the soil; seed-germination is not light-sensitive, but is favoured by alternating temperatures (Holm et al., 1977). D. sanguinalis is a C4 plant (Kissman and Groth, 1993). The minimum temperature for germination is 10-15°C, and the normal germination depth is 0.5-2 cm (Laudien and Koch., 1972). The minimum temperature for germination is 10-15°C, and the normal germination depth is 0.5-2 cm (Laudien and Koch, 1972). Suitable temperature, soil moisture and seed depth for emergence of this species are 25-35°C, 80-100% and 0-2 cm, respectively (Li et al., 1999).

King and Oliver (1994) evaluated the influence of temperature and water potential on water uptake, germination and emergence of D. sanguinalis in order to predict emergence in the field. Maximum germination at 15°C was 12% at 0 kPa and 60% at 25°C at 0 to -200 kPa osmotic potential. Maximum emergence (77%) occurred at 25°C and at soil water potential of -30 kPa. The model predicted the time of onset of germination and the time to reach maximum emergence.

In a 13-year survey in Toulouse (France) crop rotation, irrigation and soil type all had marked effect on the quantitative and qualitative composition of the soil seedbank. Echinochloa crus-galli and D. sanguinalis predominated where continuous maize and sorghum had been grown under irrigated conditions (Debaeke et al., 1990). D. sanguinalis is one of the more frequent Poaceae in soils of the flat Pampa in Argentina. The average seed population in the soil is 2,900 seeds/m² in a wheat-soyabean-maize rotation (Leguizamón et al., 1981) and 3,900 seeds/m² under a continuous maize crop (Leguizamón and Cruz, 1981).

A test of the water balance showed that water loss through cuticular transpiration was greatest in D. sanguinalis compared with four broad-leaved weeds, although the length of time drought-stressed leaves were able to survive was greater in D. sanguinalis than Papaver rhoeas, Matricaria perforata and Alopecurus myosuroides (Kazinczi and Hunyadi, 1992).The water potential of rice was nearly always significantly lower than D. sanguinalis among other weed species (IRRI, 1979).

Size and composition of the weed seed bank were evaluated after 5 years of maize continuous cropping under four crop management systems in sowing. Weed seed bank size was largest under an organic system and smallest under a conventional system. D. sanguinalis showed differential responses to tillage and weed control methods carried out within maize management systems. It was one of the most troublesome weeds for the cropping system under study (Barberi et al., 1998)

In a long-term study where tillage systems were compared in different rotations, Puricelli and Tuesca, (1997) found that the population density of D. sanguinalis was greater in no-tillage than in conventional tilled plots. In a soyabean-maize rotation, D. sanguinalis was the dominant summer annual showing an increase in density during the course of the experiment in no-tillage plots.

Nisensohn et al. (1997) studied the effect of different tillage systems on the soil seed bank composition and weed seedling emergence in a soyabean-maize rotation. D. sanguinalis was the dominant species in both tillage systems but it was significantly more dense in no tillage systems. Similar results were reported by Zanin et al. (1997).

Correlations between seed bank and seedling densities of D. sanguinalis were significant in no-tillage but not in mouldboard plough systems (Cardina et al., 1996).

The following organisms have been reported on D. sanguinalis:

Insects: Poanes melane (Barbehenn, 1994); Empoasca fabae (Smith et al., 1994; Lamp et al., 1984); Mayetiola destructor (Zeiss et al., 1993) and Spodoptera frugiperda (Pencoe and Martin., 1981). The Argentine stem weevil (Listronotus bonariensis) uses D. sanguinalis as an alternative host for oviposition (Firth et al., 1993).

Nematodes: Meloidogyne arenaria and M. incognita were recovered from D. sanguinalis in tobacco fields (Tedford and Fortnum, 1988). Bendixen (1982) lists 11 nematodes species and two arthropod species. Pratylenchus penetrans has been found in D. sanguinalis roots in Florida, USA, by Lehman (1990). In greenhouse and field studies, D. sanguinalis showed tolerance to Meloidogyne spp. (Kim et al., 1998).

Fungi: Magnaporthe grisea, a serious rice pest, uses D. sanguinalis as an alternative overwintering host (Yaegashi and Asaga, 1981). M. grisea isolates were collected on D. sanguinalis in paddy fields in China. It has been suggested that weed hosts of the rice blast pathogen might be epidemiologically important and have a direct bearing on the disease cycle (Du et al., 1997).

D. sanguinalis was identified as a host for Rhizoctonia solani in soyabean-producing regions of Louisiana, USA (Black et al., 1996, 1998).

Dissanayake et al. (1997) suggested that D. sanguinalis can serve as hosts for Pythium arrhenomanes and may play roles in the epidemiology of Pythium root rot on sugarcane fields in Louisana, USA.

Viruses: Rice black-streaked dwarf virus (Choi et al., 1989) and maize rough dwarf virus associated with Rio IV Disease [mal de Rio Cuarto disease] in Argentinian maize (Nome and Teyssandier, 1984) are both cited as infecting D. sanguinalis.

Chen et al. (1998) found that D. sanguinalis and its transformants were sensitive to maize streak monogeminivirus (MSV); the weed is, therefore, an ideal model system for testing genetically engineered resistance to MSV.

Many of the species listed as natural enemies are better known as polyphagous pests of graminaceous and other crops. Others require evaluation before they can be considered as potential biological control agents.

Animal feed, fodder, forage

• Fodder/animal feed
• Forage

There are about 200 species of Digitaria, all superficially similar with digitate or sub-digitate inflorescences. Precise identification requires at least x10 hand-lens or ideally a low-power microscope, for close observation of the details and arrangement of the spikelets. Some species are perennial, have distinct growth habits or have spikelets in groups of three rather than two. Otherwise annual species are mainly distinguished on the basis of the shape, lengths and hairiness of the glumes and lemmas.

The species closest to D. sanguinalis is D. ciliaris, which differs in mainly having a longer upper glume, normally more than half the length of the spikelet, and in not having the lateral nerves of the upper lemma scabrid towards the tip of the spikelet. Neither of these characters is very distinct and intermediates occur. In the USA, D. ciliaris is said to differ in having leaf blades only sparsely hairy while those of D. sanguinalis are hairy (papillose-pilose) near the throat on the upper surface, often densely so (Gleason and Cronquist, 1991). In North America, D. ciliaris is known as southern crabgrass and has a more southern distribution (D. ciliaris). Bor (1960) remarks that Indian specimens of D. ciliaris are more robust than D. sanguinalis.

Each region of the world has other annual species which commonly occur as weeds and which can also be confused with D. sanguinalis. These include D. horizontalis in Africa and America, with more racemes, shorter, narrower spikelets and a slightly hairy rachis. D. nuda, mainly in Africa, differs with smaller spikelets and absence of lower glume. In Asia, D. timorensis differs mainly in having narrower spikelets with lower glume less than half as long as the spikelet.

Due to the variable regulations around (de)registration of pesticides, your national list of registered pesticides or relevant authority should be consulted to determine which products are legally allowed for use in your country when considering chemical control. Pesticides should always be used in a lawful manner, consistent with the product's label.

Allelophatic effects on D. sanguinalis

There is evidence for allelopathic effects of varieties of Festuca arundinacea on D. sanguinalis and other species. Tjis was determined using extracts made from 10 g of F. arundinacea leaves soaked in 100 ml of water for 24 hours (Peters and Mohammed-Zam, 1981).

Hwang et al. (1997) found that water extracts from lilac (Syringa vulgaris) leaves inhibited seed germination and root growth of D. sanguinalis.

Water extracts from Ginkgo biloba leaves, collected during different seasons, markedly inhibited the germination and growth of D. sanguinalis indicating the presence of biologically active substances (Nam et al., 1997).

Cultural Control

The use of trash as mulch and of mechanical weeding have proved to be successful in controlling D. sanguinalis in sugarcane (Mann and Chakor, 1993).

The effects of solarization have been investigated using different grades of transparent polythylene film. All thicknesses, ranging from 150-400 µm, were suitable for effective control of D. sanguinalis, although the film should be kept in place for 30-45 days to achieve high control levels (Nasr, 1993; Vizantinopoulos and Katranis, 1993).

On-row flaming and hoeing in a single operation has been tested with a machine designed in Italy for arable and vegetable crops (Casini et al., 1994).

Mechanical Control

Mechanical control of D. sanguinalis may be achieved with any of the tools used in conventional farming or where row crops are grown.

Chemical Control

D. sanguinalis may be chemically controlled under a variety of agroecosystems. Preplanting herbicides such as dinitroanilines (pendimethalin) may be used in maize, soyabean and cotton. Pre-emergence herbicides such as the amides or acetanilides (metolachlor) are effective in control of D. sanguinalis in soyabean, maize, sweet potato and sugarcane. Post-emergence herbicides clethodim, fenoxaprop-ethyl and sethoxydim may be used in lucerne, soyabean and sunflower.

Chemical control of D. sanguinalis may also be achieved in beans, broccoli, cabbage and cauliflower with sethoxydim. Sulfonylurea compounds, such as rimsulfuron, are effective for weed control in maize. Fenoxaprop-ethyl is used in sugarbeet. In rice, oxadiazon and quinclorac are used in many areas, whereas chlorthal and pendimethalin have been successfully tested in flower bulb nurseries.

In nursery trials of Pyrus, Zelkova, Acer and Fraxinus, Kuhns et al. (1998) found that oxyfluorfen and thiazopyr reduced D. sanguinalis cover.

DPX-PE 350 (sodium 2-chloro-6-(4,5-dimethoxypyrimidin-2-ythio) benzoate) reduced the control of D. sanguinalis when mixed with fluazifop-P, sethoxydim, chlethodim and quizalofop-P at recommended rates. Tank-mix combinations of sethoxydim + bentazone-Na, imazaquin and chlorimuron-ethyl were antagonistic in the control of D. sanguinalis, Eleusine indica and Panicum dichotomiflorum (Holshouser and Coble, 1990).

Culpepper and York (1998) compared weed control in glyphosate-tolerant cotton with various glyphosate and traditional herbicide systems. The standard system of trifluralin pre-plant incorporated and fluometuron pre-emergence followed by fluometuron plus MSMA post-emergence directed 3 to 4 weeks after planting and cyanazine plus MSMA post-emergence directed 6 to 7 weeks after planting controlled D. sanguinalis by at least 98% at late season. Glyphosate applied once did not adequately control D. sanguinalis.

In maize, the efficacy of nicosulfuron on D. sanguinalis was affected by the weed size. Control decreased dramatically at the 7-leaf stage. According to the economic threshold of D. sanguinalis control in maize, nicosulfuron should be applied at the 3-, 4- and 5-leaf stages (Wu et al., 1999)

Mixing bromoxynil with clethodim or sethoxydim had no effect on control of D. sanguinalis but the rate of fluazifop-P, fluazifop-P plus fenoxaprop-P, or quizalofop-P required for 80% control was increased by 180% to 290%. Antagonism of D. sanguinalis control with mixtures of quizalofop-P and bromoxynil increased as the rate of bromoxynil increased. Antagonism was alleviated by applying bromoxynil 6 days before the graminicides or 3 or 6 days after the graminicides (Culpepper et al., 1998, 1999).

Fenoxaprop, 2,4-D, pendimethalin, MSMA, quinclorac and their mixtures gave a good level of control of D. sanguinalis on an established stand of Kentucky bluegrass (Poa pratensis) (Street and Stewart, 1997).

In imidazolinone-resistant maize, imazethapyr provided less than 43% control of D. sanguinalis (Krausz and Kapusta, 1998).

Gimenez et al. (1998) studied annual grass control by glyphosate plus bentazone, chlorimuron, fomesafen, or imazethapyr mixtures. Neither D. sanguinalis or Brachiaria platyphylla were controlled by bentazone, fomesafen or chlorimuron. Imazethapyr controlled D. sanguinalis and B. platyphylla by 30 and 72%, respectively. Glyphosate controlled both grasses by 100%.

In no-till narrow-row soyabean production, the reduction of the D. sanguinalis population was greater with sequential preplant metolachlor + imazaquin followed by early post-emergence or post-emergence imazethapyr than with pre-plant metolachlor + imazaquin or early post-emergence/post-emergence imazethapyr alone (Johnson et al., 1998).

In a tall fescue (Festuca arundinacea) turf, an application of prodiamine, sequential applications of oxadiazon in late February, followed by fenoxaprop in June resulted in 85-96% D. sanguinalis control in late August. Control was similar in mid-August, when pendimethalin, dithiopyr or oryzalin was followed by fenoxaprop, but control was 74% by late August. Better weed control was found in combinations with fenoxaprop than in combinations with MSMA (Johnson, 1997).

Guery et al. (1996) studied the effects of herbicides applied pre-budburst in field trials in vineyards. Treatments assessed included single applications of simazine + diuron in combination with isoxaben, oryzalin or norflurazon, and simazine and diuron as single or two split applications. Single applications of simazine + diuron gave inadequate control of D. sanguinalis but split applications often gave more or less satisfactory control. The other combinations gave good control of this weed and the norflurazon combination gave good control of most grassy weeds.

In maize, Sanchis et al. (1996) determined the efficacy of weed control of single post-emergence applications of rimsulfuron + wetter. Results indicated that >95% control of D. sanguinalis was achieved 15 days after treatment with the rimsulfuron treatment and this was significantly better than the results achieved with pre-emergence herbicides.

In gladiolus fields, the most effective herbicides for controlling D. sanguinalis were simazine, napropamide, linuron and pendimethalin. These herbicides gave excellent weed control with very slight injury at the early stage of gladiolus growth but no injury to flowers (Kwon et al., 1996).

In potato fields, rimsulfuron applied PRE or POST gave 92% control of D. sanguinalis. Reduced rates of rimsulfuron plus metribuzin, applied pre- or post-, gave poor control of this species (Robinson et al., 1996).

Resistance to herbicides

A few cases of chloroplastic resistance biotypes to atrazine has been reported from maize fields in Portugal (Monteiro and Rocha, 1992). Increasing resistance to atrazine was noted in populations of D. sanguinalis in France (Grignac, 1978).

Wiederholt and Stoltenberg (1995) found a D. sanguinalis accession that showed 337- and 59-fold resistance to sethoxyidim and fluazifop-P, respectively, relative to a susceptible accession. The resistance to fenoxaprop, haloxyfop, quizalofop, and diclofop ranged from 18- to 29-fold and this accession was only 7-fold resistant to clethodim. In another study Wiederholt and Stoltenberg (1996) reported similar fitness between D. sanguinalis accessions resistant or susceptible to acetyl-coenzyme A carboxylase inhibitors.

Resistance to fluazifop has also been reported from both the USA and Australia (Heap, 1997). Hidayat and Preston (1997) found a D. sanguinalis biotype from Australia that showed resistance to fluazifop-P-butyl. This population also had a 9-fold resistance to haloxyfop-ethoxyethyl and a 6-fold resistance to quizalofop-P-ethyl; it also exhibited some resistance to sethoxydim.

Integrated Management

The effect of various weed control treatments and different row spacings (narrow = 30 cm, wide = 60 cm) for soyabean was investigated in India (Singh and Sharma, 1989). Uptake of N, P and K by weeds, particularly Echinochloa colonum, D. sanguinalis and Eleusine indica, was reduced at narrow row spacing of the crop.