Digitaria insularis (L.) Fedde Family -Poaceae Common Names(s) - sour grass, barba de indio, rabo de zorra Synonym(s) - Andropogon insularis L. (basionym); Panicum leucophaeum Kunth; Tricachne insularis (L.) Nees; Valota insularis (L.) Chase

Answer

Score

1.01

Is the species highly domesticated?

y=-3, n=0

n

0

1.02

Has the species become naturalized where grown?

y=1, n=-1

1.03

Does the species have weedy races?

y=-1, n=-1

2.01

Species suited to tropical or subtropical climate(s) (0-low; 1-intermediate; 2-high) – If island is primarily wet habitat, then substitute “wet tropical” for “tropical or subtropical”

See Append 2

2

2.02

Quality of climate match data (0-low; 1-intermediate; 2-high) see appendix 2

2

2.03

Broad climate suitability (environmental versatility)

y=1, n=0

y

1

2.04

Native or naturalized in regions with tropical or subtropical climates

y=1, n=0

y

1

2.05

Does the species have a history of repeated introductions outside its natural range?

y=-2, ?=-1, n=0

y

3.01

Naturalized beyond native range y = 1*multiplier (see Append 2), n= question 2.05

y

2

3.02

Garden/amenity/disturbance weed y = 1*multiplier (see Append 2)

n=0

y

2

3.03

Agricultural/forestry/horticultural weed y = 2*multiplier (see Append 2)

n=0

y

4

3.04

Environmental weed y = 2*multiplier (see Append 2)

n=0

n

0

3.05

Congeneric weed y = 1*multiplier (see Append 2)

n=0

y

2

4.01

Produces spines, thorns or burrs

y=1, n=0

n

0

4.02

Allelopathic

y=1, n=0

4.03

Parasitic

y=1, n=0

n

0

4.04

Unpalatable to grazing animals

y=1, n=-1

y

1

4.05

Toxic to animals

y=1, n=0

n

0

4.06

Host for recognized pests and pathogens

y=1, n=0

4.07

Causes allergies or is otherwise toxic to humans

y=1, n=0

n

0

4.08

Creates a fire hazard in natural ecosystems

y=1, n=0

y

1

4.09

Is a shade tolerant plant at some stage of its life cycle

y=1, n=0

4.10

Tolerates a wide range of soil conditions (or limestone conditions if not a volcanic island)

y=1, n=0

y

1

4.11

Climbing or smothering growth habit

y=1, n=0

n

0

4.12

Forms dense thickets

y=1, n=0

y

1

5.01

Aquatic

y=5, n=0

n

0

5.02

Grass

y=1, n=0

y

1

5.03

Nitrogen fixing woody plant

y=1, n=0

n

0

5.04

Geophyte (herbaceous with underground storage organs -- bulbs, corms, or tubers)

y=1, n=0

n

0

6.01

Evidence of substantial reproductive failure in native habitat

y=1, n=0

n

0

6.02

Produces viable seed.

y=1, n=-1

y

1

6.03

Hybridizes naturally

y=1, n=-1

6.04

Self-compatible or apomictic

y=1, n=-1

6.05

Requires specialist pollinators

y=-1, n=0

n

0

6.06

Reproduction by vegetative fragmentation

y=1, n=-1

y

1

6.07

Minimum generative time (years) 1 year = 1, 2 or 3 years = 0, 4+ years = -1

See left

1

1

7.01

Propagules likely to be dispersed unintentionally (plants growing in heavily trafficked areas)

y=1, n=-1

y

1

7.02

Propagules dispersed intentionally by people

y=1, n=-1

n

-1

7.03

Propagules likely to disperse as a produce contaminant

y=1, n=-1

y

1

7.04

Propagules adapted to wind dispersal

y=1, n=-1

y

1

7.05

Propagules water dispersed

y=1, n=-1

n

-1

7.06

Propagules bird dispersed

y=1, n=-1

n

-1

7.07

Propagules dispersed by other animals (externally)

y=1, n=-1

n

-1

7.08

Propagules survive passage through the gut

y=1, n=-1

8.01

Prolific seed production (>1000/m2)

y=1, n=-1

8.02

Evidence that a persistent propagule bank is formed (>1 yr)

y=1, n=-1

y

1

8.03

Well controlled by herbicides

y=-1, n=1

y

-1

8.04

Tolerates, or benefits from, mutilation, cultivation, or fire

y=1, n=-1

y

1

8.05

Effective natural enemies present locally (e.g. introduced biocontrol agents)

y=-1, n=1

Total score:

20

Notes

Source

1.01

No evidence.

1.02

1.03

2.01

(1) Native to: United States (Florida, Texas, Arizona); Belize; Costa Rica; El Salvador; Guatemala; Honduras; Nicaragua; Panama; Antigua; Bahamas; Cuba; Grenada; Guadeloupe; Hispaniola; Jamaica; Martinique; Montserrat; French Guiana; Guyana; Suriname; Venezuela; Brazil; Bolivia; Colombia; Ecuador; Peru; Argentina; Paraguay; Uruguay.

(1) http://www.ars-grin.gov/cgi-bin/npgs/html/taxon.pl?14028 [Cited 2009 November 13].

2.02

(1) Native to: United States (Florida, Texas, Arizona); Belize; Costa Rica; El Salvador; Guatemala; Honduras; Nicaragua; Panama; Antigua; Bahamas; Cuba; Grenada; Guadeloupe; Hispaniola; Jamaica; Martinique; Montserrat; French Guiana; Guyana; Suriname; Venezuela; Brazil; Bolivia; Colombia; Ecuador; Peru; Argentina; Paraguay; Uruguay.

(1) http://www.ars-grin.gov/cgi-bin/npgs/html/taxon.pl?14028 [Cited 2009 November 13].

2.03

(1) Digitaria insularis is known from 0-2000 m in Bolivia. It inhabits dry valleys; tucuman; rain; campos; chiquitano and dry chaqueo. (2) Digitaria insularis has been collected from areas of Arizona, USA and Mexico from elevations from 450 -1450 m.

(1) http://www.efloras.org/florataxon.aspx?flora_id=40&taxon_id=242430670 [Cited 2009 November 13]. (2) http://74.125.155.132/search?q=cache:77zOnPUCbC0J:loco.biosci.arizona.edu/herbarium/db/spec_csv.php%3Fsql%3DSELECT
%2Bs.observation_id%2BAS%2Bspec_id%252C%2Bs.accession_number%2BAS%2Baccnum%252C%2Bs.collector
%252C%2B%250A%2509s.collection_number%2BAS%2Bcollnum%252C%2Bs.other_collectors%252C%2Bs.taxon_id
%252C%2Bs.taxon%2BAS%2Btaxon%252C%2BIF(s.taxon%2BLIKE%2B%27%2525aceae%27%252CNULL%
252Cs.taxon)%2BAS%2Btaxon_display%252C%2Bs.author%2BAS%2Bauthor%252C%250A%2509s.orig_family%2BAS
%2Bfamily%252C%2Bs.family%2BAS%2Baccepted_family%252C%2Bs.collection_date%2BAS%2Bcolldate%252C%2B%250A
%2509s.country%252C%2Bs.state_province%252C%2Bs.county_parish%252C%2Bs.locality_description
%2BAS%2Blocality%252C%250A%2509s.habitat%252C%2Bs.associated_species
%2BAS%2Bassoc_species%252C%2Bs.specimen_description%2BAS%2Bplant_description%252C%2B%
250A%2509s.latitude%2BAS%2Blat%252C%2Bs.longitude%2BAS%2Blng%252C%2Bs.elev_m%2BAS%2Belevation

2.04

(1) Native to: United States (Florida, Texas, Arizona); Belize; Costa Rica; El Salvador; Guatemala; Honduras; Nicaragua; Panama; Antigua; Bahamas; Cuba; Grenada; Guadeloupe; Hispaniola; Jamaica; Martinique; Montserrat; French Guiana; Guyana; Suriname; Venezuela; Brazil; Bolivia; Colombia; Ecuador; Peru; Argentina; Paraguay; Uruguay.

(1) http://www.ars-grin.gov/cgi-bin/npgs/html/taxon.pl?14028 [Cited 2009 November 13]. (2) Wagner, W.L., Herbst, D.R., Sohmer, S.H., 1999. Manual of the Flowering Plants of Hawaii. Bishop Museum Press, Honolulu.

2.05

(1) Digitaria insularis was introduced to Hawaii and Malesia as a weed. [most likely introduced as an agricultural contaminant, see 3.03]

(1) Rua, G.H. 2003. Growth forms, branching patterns, and inflorescence structure in Digitaria sect. Trichachne (Poaceae, Paniceae). Flora 198:178-187.

3.01

(1) In Hawaii, naturalized in abandoned fields, disturbed sites, and along roadsides, 0-340 m on all the main islands except Niihau

(1) Wagner, W.L., Herbst, D.R., Sohmer, S.H., 1999. Manual of the Flowering Plants of Hawaii. Bishop Museum Press, Honolulu.

3.02

(1) "Forms dense stands in mesic pastures and disturbed forests.  Infests disturbed areas in mesic and dry natural areas, roadsides, and waste areas" (2) In Hawai‘i, "naturalized in abandoned fields, disturbed sites, and along roadsides, 0-340 m"

(1) Motooka, P., Castro, L., Nelson, D., Nagai, G., Ching, L., 2003. Weeds of Hawaii's Pastures and Natural Areas; An Identification and Management Guide. College of Tropical Agriculture and Human Resources, University of Hawaii at Manoa, Honolulu.

3.03

(1) Digitaria insularis is a weed in hardwood nurseries. (2) D. insularis invades soybean crops in Brazil and Paraguay. (3) A weed of rice in Belize. (4) Digitaria insularis adversely affects pasture production in the Markham and Ramu Valleys of Papua New Guinea.

(1) http://www.fs.fed.us/rm/pubs/rmrs_p058/rmrs_p058_080_084.pdf [Cited 2009 November 14]. (2) http://www.weedscience.org/Case/Case.asp?ResistID=5350[Cited 2009 November 14]. (3) http://www.fao.org/agriculture/crops/core-themes/theme/biodiversity/weeds/db-countries/b/en/[Cited 2009 November 14]. (4) Chadhokar, P.A., 1976. Control of Digitaria insularis (L.) Mez in Tropical Pastures. Tropical Pest Management 22, 79 - 85.

3.04

No evidence.

3.05

(1) Digitaria velutina is a quickly invading common weed of arable land in Africa. (2) "Digitaria ternata is a very widespread and successful weed, recorded by Holm et al. (1979) as a “principal” weed in Israel and Jordan and a “common” weed in Australia, Lebanon and Morocco. It can be abundant in upland rice in Indonesia (Kostermans et al., 1987), is common in cereal crops in Ethiopia (Stroud and Parker, 1989) and can be serious in cereal crops in East Africa (Terry, 1984). Reed (1977) notes it as a weed of arable land, frequently invading pastures. Wells et al. (1986) list it as behaving as a ruderal, agrestal, and pasture weed in South Africa, competitive and able to replace other vegetation."

(1) http://keys.lucidcentral.org/keys/FNW/FNW%20grasses/html/fact%20sheets/Digitaria%20velutina.htm [Cited 2009 November 14]. (2) http://keys.lucidcentral.org/keys/FNW/FNW%20grasses/html/fact%20sheets/Digitaria%20velutina.htm [Cited 2009 November 14].

4.01

(1) No spines, burrs or thorns.

(1) Wagner, W.L., Herbst, D.R., Sohmer, S.H., 1999. Manual of the Flowering Plants of Hawaii. Bishop Museum Press, Honolulu.

4.02

Unknown

4.03

(1) Not parasitic.

(1) Wagner, W.L., Herbst, D.R., Sohmer, S.H., 1999. Manual of the Flowering Plants of Hawaii. Bishop Museum Press, Honolulu.

4.04

(1) Avoided by livestock. (2) Unpalatable to livestock.

(1) http://www.ctahr.hawaii.edu/deFrankJ/Weed_ID_website/images/BLACK%20AND%20
WHT%20SCANS%20HHW/grassy%20weed%20scans/pages/digitaria%20insularis.htm [Cited 2009 November 14]. (2) Chadhokar, P.A., 1976. Control of Digitaria insularis (L.) Mez in Tropical Pastures. Tropical Pest Management 22, 79 - 85.

4.05

(1) No evidence of toxicity listed in PubMed. (2) No evidence of toxicity listed in ToxNet.

(1) http://www.ncbi.nlm.nih.gov/sites/entrez [Cited 2009 November 13]. (2) http://toxnet.nlm.nih.gov/cgi-bin/sis/search [Cited 2009 November 13].

4.06

Unknown (1) Herrbaspirillum rubrisubalicans has been isolated from Digitaria insularis.

(1) http://books.google.com/books?id=9cwgo-9IyTUC&pg=PA631&lpg=PA631&dq=digitaria+insularis+%2B+%22soil%22&source=bl&ots=lQwdbfshYy&sig=rfPwfmEUlNjbFc_Z
f5PGkqzmxuE&hl=en&ei=eMYBS4T1HJXKsAOEqtiHCw&sa=X&oi=book_result&ct=result&resnum
=3&ved=0CA8Q6AEwAg#v=onepage&q=digitaria%20insularis%20%2B%20%22soil%22&f=false [Cited 2009 November 13].

4.07

(1) No evidence of toxicity listed in PubMed. (2) No evidence of toxicity listed in ToxNet.

(1) http://www.ncbi.nlm.nih.gov/sites/entrez [Cited 2009 November 13]. (2) http://toxnet.nlm.nih.gov/cgi-bin/sis/search [Cited 2009 November 13].

4.08

(1) "The purpose of this study was to assess the feasibility of restoring an indigenous Heteropogon grassland at the Puukohola Heiau National Historic Site, where introduced Buffel grass (Cenchrus ciliaris) is now dominant. Heteropogon seeds (50 seedlings/m2) were added to replicate plots within a Cenchrus grassland. Some plots were subjected to one-time herbicide or hand-pulling treatments to remove established Cenchrus. Because Hawaiians historically used fire to promote Heteropogon grasslands, the plots were burned biennially." Water supplementation in the plots promoted the growth of Digitaria insularis from the seedbank. "Digitaria cover was significantly greater in the burn + herbicide treatment than in the unburned treatment. However after supplemental watering was terminated in March 2002, Digitaria quickly declined, and by June 2002 it had become rare in all treatments." (2) Digitaria insularis is one of several grass species that dominate in fire-induced grasslands occurring after fires in the Chaco forest in the southwest part of Santiago del Estero.

(1) Daehler, C.C., Goergen, E.M. 2005. Experimental restoration of an indigenous Hawaiian grassland after invasion by Buffel grass (Cenchrus ciliaris). Restoration Ecology 13 (2):380-389. (2) Kunst, C., Monti, E., Pérez, H., Godoy, J. 2006. Assessment of the rangelands of southwestern Santiago del Estero, Argentina, for grazing management and research. Journal of Environmental Management. 80:248-265.

4.09

(1) The genus Digitaria is shade adapted.

(1) Kunst, C., Monti, E., Pérez, H., Godoy, J. 2006. Assessment of the rangelands of southwestern Santiago del Estero, Argentina, for grazing management and research. Journal of Environmental Management. 80:248-265.

4.10

(1) Digitaria insularis has been collected from sandy, alkali, clay, granite, and rocky soils in Arizona, USA and Mexico.

(1) http://74.125.155.132/search?q=cache:77zOnPUCbC0J:loco.biosci.arizona.edu/herbarium/db/spec_csv.php%3Fsql%3DSELECT
%2Bs.observation_id%2BAS%2Bspec_id%252C%2Bs.accession_number%2BAS%2Baccnum%252C%2Bs.collector%252C%2B%250A
%2509s.collection_number%2BAS%2Bcollnum%252C%2Bs.other_collectors%252C%2Bs.taxon_id%252C%2Bs.taxon%2BAS%2Btaxon
%252C%2BIF(s.taxon%2BLIKE%2B%27%2525aceae%27%252CNULL
%252Cs.taxon)%2BAS%2Btaxon_display%252C%2Bs.author%2BAS%2Bauthor%252C%250A%2509s.orig_family%2
BAS%2Bfamily%252C%2Bs.family%2BAS%2Baccepted_family%252C%2Bs.collection_date%2BAS%2Bcolldate%252C%2B%250A%2509s.country
%252C%2Bs.state_province%252C%2Bs.county_parish%252C%2Bs.locality_description%2BAS%2Blocality%252C%250A%2509s.
habitat%252C%2Bs.associated_species%2BAS%2Bassoc_species%252C%2Bs.specimen_description%2BAS%2Bplant_description
%252C%2B%250A%2509s.latitude%2BAS%2Blat%252C%2Bs.longitude%2BAS%2Blng%252C%2Bs.elev_m%2BAS%2
Belevation_m%252C%2B%250A%2509s.determiner%252C%2Bs.determination_date%2BAS%2Bdet_date%252C%2Bs.is_proper_type

4.11

(1) Tufted perennials 100-150 cm tall.

(1) Wagner, W.L., Herbst, D.R., Sohmer, S.H., 1999. Manual of the Flowering Plants of Hawaii. Bishop Museum Press, Honolulu.

4.12

(1) "Once established it spreads rapidly and forms almost solid stands." Upright perennial 3-5 feet high.

(1) http://www.ctahr.hawaii.edu/deFrankJ/Weed_ID_website/images/BLACK%20AND%20WHT%20SCANS
%20HHW/grassy%20weed%20scans/pages/digitaria%20insularis.htm [Cited 2009 November 14].

5.01

(1) Terrestrial

(1) Wagner, W.L., Herbst, D.R., Sohmer, S.H., 1999. Manual of the Flowering Plants of Hawaii. Bishop Museum Press, Honolulu.

5.02

(1) Poaceae

(1) Wagner, W.L., Herbst, D.R., Sohmer, S.H., 1999. Manual of the Flowering Plants of Hawaii. Bishop Museum Press, Honolulu.

5.03

(1) Perennial grass.

(1) Wagner, W.L., Herbst, D.R., Sohmer, S.H., 1999. Manual of the Flowering Plants of Hawaii. Bishop Museum Press, Honolulu.

5.04

(1) Perennial grass.

(1) Wagner, W.L., Herbst, D.R., Sohmer, S.H., 1999. Manual of the Flowering Plants of Hawaii. Bishop Museum Press, Honolulu.

6.01

No evidence.

6.02

(1) Propagated by seed and runners.

(1) http://www.ctahr.hawaii.edu/deFrankJ/Weed_ID_website/images/BLACK%20AND%20WHT%20SCANS
%20HHW/grassy%20weed%20scans/pages/digitaria%20insularis.htm [Cited 2009 November 14].

6.03

Unknown

6.04

Unknown

6.05

(1) Poaceae. Wind-pollinated.

(1) Wagner, W.L., Herbst, D.R., Sohmer, S.H., 1999. Manual of the Flowering Plants of Hawaii. Bishop Museum Press, Honolulu.

6.06

(1) Propagated by seed and runners.

(1) http://www.ctahr.hawaii.edu/deFrankJ/Weed_ID_website/images/BLACK%20AND%20WHT%20SCANS
%20HHW/grassy%20weed%20scans/pages/digitaria%20insularis.htm [Cited 2009 November 14].

6.07

(1) In this experiment, Digitaria insularis flowered in 105 days or less under, 11, 13, and 15 photoperiods.

(1) Pyon, J.Y., Whitney, A.S., Nishimoto, R.K., 1977. Biology of Sourgrass and Its Competition with Buffelgrass and Guineagrass. Weed Science 25, 171-174.

7.01

(1) In Hawaii, naturalized in abandoned fields, disturbed sites, and along roadsides, 0-340 m on all the main islands except Niihau (2) Digitaria insularis was introduced to Hawaii and Malesia as a weed.

(1) Wagner, W.L., Herbst, D.R., Sohmer, S.H., 1999. Manual of the Flowering Plants of Hawaii. Bishop Museum Press, Honolulu. (2) Rua, G.H. 2003. Growth forms, branching patterns, and inflorescence structure in Digitaria sect. Trichachne (Poaceae, Paniceae). Flora 198:178-187.

7.02

(1) In Hawaii, naturalized in abandoned fields, disturbed sites, and along roadsides, 0-340 m on all the main islands except Niihau (2) Digitaria insularis was introduced to Hawaii and Malesia as a weed.

(1) Wagner, W.L., Herbst, D.R., Sohmer, S.H., 1999. Manual of the Flowering Plants of Hawaii. Bishop Museum Press, Honolulu. (2) Rua, G.H. 2003. Growth forms, branching patterns, and inflorescence structure in Digitaria sect. Trichachne (Poaceae, Paniceae). Flora 198:178-187.

7.03

(1) Digitaria insularis is a weed in hardwood nurseries. (2) D. insularis invades soybean crops in Brazil and Paraguay. (3) A weed of rice in Belize. (4) Digitaria insularis adversely affects pasture production in the Markham and Ramu Valleys of Papua New Guinea.

(1) http://www.fs.fed.us/rm/pubs/rmrs_p058/rmrs_p058_080_084.pdf [Cited 2009 November 14]. (2) http://www.weedscience.org/Case/Case.asp?ResistID=5350[Cited 2009 November 14]. (3) http://www.fao.org/agriculture/crops/core-themes/theme/biodiversity/weeds/db-countries/b/en/[Cited 2009 November 14]. (4) Chadhokar, P.A., 1976. Control of Digitaria insularis (L.) Mez in Tropical Pastures. Tropical Pest Management 22, 79 - 85.

7.04

(1) Seeds are wind-dispersed.

(1) http://www.ctahr.hawaii.edu/deFrankJ/Weed_ID_website/images/BLACK%20AND%20WHT%20SCANS
%20HHW/grassy%20weed%20scans/pages/digitaria%20insularis.htm [Cited 2009 November 14].

7.05

(1) Seeds are wind-dispersed.

(1) http://www.ctahr.hawaii.edu/deFrankJ/Weed_ID_website/images/BLACK%20AND%20WHT%20SCANS
%20HHW/grassy%20weed%20scans/pages/digitaria%20insularis.htm [Cited 2009 November 14].

7.06

(1) Seeds are wind-dispersed.

(1) http://www.ctahr.hawaii.edu/deFrankJ/Weed_ID_website/images/BLACK%20AND%20WHT%20SCANS
%20HHW/grassy%20weed%20scans/pages/digitaria%20insularis.htm [Cited 2009 November 14].

7.07

(1) Seeds are wind-dispersed.

(1) http://www.ctahr.hawaii.edu/deFrankJ/Weed_ID_website/images/BLACK%20AND%20WHT%20SCANS
%20HHW/grassy%20weed%20scans/pages/digitaria%20insularis.htm [Cited 2009 November 14].

7.08

Unknown

8.01

(1) D. insularis produces large quantities of viable seeds.

(1) http://www.ctahr.hawaii.edu/deFrankJ/Weed_ID_website/images/BLACK%20AND%20WHT%20SCANS
%20HHW/grassy%20weed%20scans/pages/digitaria%20insularis.htm [Cited 2009 November 14].

8.02

(1) "The purpose of this study was to assess the feasibility of restoring an indigenous Heteropogon grassland at the Puukohola Heiau National Historic Site, where introduced Buffel grass (Cenchrus ciliaris) is now dominant. Heteropogon seeds (50 seedlings/m2) were added to replicate plots within a Cenchrus grassland. Some plots were subjected to one-time herbicide or hand-pulling treatments to remove established Cenchrus. Because Hawaiians historically used fire to promote Heteropogon grasslands, the plots were burned biennially." Water supplementation in the plots promoted the growth of Digitaria insularis from the seedbank. "Digitaria cover was significantly greater in the burn + herbicide treatment than in the unburned treatment. However after supplemental watering was terminated in March 2002, Digitaria quickly declined, and by June 2002 it had become rare in all treatments." Areas within a 200 m radius of the restoration site were surveyed and no Digitaria plants were found. The seedlings appeared in the plots after supplemental watering was applied. "The large number of seedlings germinating (sometimes >100 seedlings/m²) indicated that they must have been present in the soil seed bank"

(1) Daehler, C.C., Goergen, E.M. 2005. Experimental restoration of an indigenous Hawaiian grassland after invasion by Buffel grass (Cenchrus ciliaris). Restoration Ecology 13 (2):380-389.

8.03

(1) " Biotypes of Digitaria insularis have evolved resistance to Group G/9 herbicides in Brazil and Paraguay. Group G/9 herbicides are known as Glycines (Inhibition of EPSP synthase). Research has shown that these particular biotypes are resistant to glyphosate and they may be cross-resistant to other G/9 herbicides."(2) "Experiments revealed that on heavily infested pasture and fallow cultivated land it can be controlled successfully and further infestation restricted by establishing improved pastures. Proper management of both pastures and cultivated land is essential for continuing control. In productive pastures with light or patchy infestations it can be controlled by spot spraying of dalapon. Dalapon at 4-6 kg/ha (a.i.) on young stands (1-5 years) and at 6-8 kg/ha on old stands (5-10 years) in 1125 l/ha water sprayed on 3-4 week old regrowth after slashing or burning gave complete control. Higher rates are required if plants are sprayed without slashing or burning. Dalapon is most effective if applied when the plants are actively growing, with plenty of green foliage, usually after good rains." (3) "Total weed control is not always possible under no-till desiccation leading to perennial and increased number of weeds. In no-till cultivation areas with predominant occurrence of Digitaria insularis sprouts, nicosulfuron alone (60 g ha-1) and in tank mix with atrazine (40 + 1.500 g ha-1), foramsulfuron + iodosulfuron-methyl (45 + 3 g ha-1) and mesotrione in tank mix with atrazine (144 + 1.500 g ha-1) were tested in a randomized block design, with four replications. Each plot was 6 x 4 m, containing six corn culture rows. The herbicides were applied with a back spray at a constant pressure of 30 lbf pol-2, using 200 L ha-1 solution. Herbicide efficacy and toxicity were evaluated at 7, 15 and 30 days after application. During harvest, reinfesting plant cover and its degree of mechanized harvest were assessed, as well as culture yield. It can be inferred that the best control of D. insularis sprouts was obtained with nicosulfuron alone at 60 g ha-1."

(1) http://www.weedscience.org/Case/Case.asp?ResistID=5350[Cited 2009 November 14]. (2) Chadhokar, P.A., 1976. Control of Digitaria insularis (L.) Mez in Tropical Pastures. Tropical Pest Management 22, 79 - 85. (3) Timossi, P.C., 2009. Management of Digitaria insularis sprouts under no-till corn cultivation. Planta Daninha 27, 175-179. 

8.04

(1) "The purpose of this study was to assess the feasibility of restoring an indigenous Heteropogon grassland at the Puukohola Heiau National Historic Site, where introduced Buffel grass (Cenchrus ciliaris) is now dominant. Heteropogon seeds (50 seedlings/m2) were added to replicate plots within a Cenchrus grassland. Some plots were subjected to one-time herbicide or hand-pulling treatments to remove established Cenchrus. Because Hawaiians historically used fire to promote Heteropogon grasslands, the plots were burned biennially." Water supplementation in the plots promoted the growth of Digitaria insularis from the seedbank. "Digitaria cover was significantly greater in the burn + herbicide treatment than in the unburned treatment. However after supplemental watering was terminated in March 2002, Digitaria quickly declined, and by June 2002 it had become rare in all treatments." (2) Digitaria insularis is one of several grass species that dominate in fire-induced grasslands occurring after fires in the Chaco forest in the southwest part of Santiago del Estero.

(1) Daehler, C.C., Goergen, E.M. 2005. Experimental restoration of an indigenous Hawaiian grassland after invasion by Buffel grass (Cenchrus ciliaris). Restoration Ecology 13 (2):380-389. (2) Kunst, C., Monti, E., Pérez, H., Godoy, J. 2006. Assessment of the rangelands of southwestern Santiago del Estero, Argentina, for grazing management and research. Journal of Environmental Management. 80:248-265.

8.05

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