Research directed by C. Daehler (UH Botany) with funding from the Kaulunani Urban Forestry Program and US Forest Service

Information on Risk Assessments
Original risk assessment

Pennisetum clandestinum (kikuyu grass)

Answer

1.01

Is the species highly domesticated?

y=-3, n=0

n

1.02

Has the species become naturalized where grown?

y=-1, n=-1

y

1.03

Does the species have weedy races?

y=-1, n=-1

n

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

2.04

Native or naturalized in regions with tropical or subtropical climates

y=1, n=0

y

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

3.02

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

n=0

y

3.03

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

n=0

y

3.04

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

n=0

n

3.05

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

n=0

y

4.01

Produces spines, thorns or burrs

y=1, n=0

n

4.02

Allelopathic

y=1, n=0

y

4.03

Parasitic

y=1, n=0

n

4.04

Unpalatable to grazing animals

y=1, n=-1

n

4.05

Toxic to animals

y=1, n=0

n

4.06

Host for recognized pests and pathogens

y=1, n=0

n

4.07

Causes allergies or is otherwise toxic to humans

y=1, n=0

n

4.08

Creates a fire hazard in natural ecosystems

y=1, n=0

n

4.09

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

y=1, n=0

n

4.1

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

y=1, n=0

y

4.11

Climbing or smothering growth habit

y=1, n=0

n

4.12

Forms dense thickets

y=1, n=0

y

5.01

Aquatic

y=5, n=0

n

5.02

Grass

y=1, n=0

y

5.03

Nitrogen fixing woody plant

y=1, n=0

n

5.04

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

y=1, n=0

n

6.01

Evidence of substantial reproductive failure in native habitat

y=1, n=0

n

6.02

Produces viable seed.

y=1, n=-1

y

6.03

Hybridizes naturally

y=1, n=-1

6.04

Self-compatible or apomictic

y=1, n=-1

y

6.05

Requires specialist pollinators

y=-1, n=0

n

6.06

Reproduction by vegetative fragmentation

y=1, n=-1

y

6.07

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

See left

1

7.01

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

y=1, n=-1

y

7.02

Propagules dispersed intentionally by people

y=1, n=-1

y

7.03

Propagules likely to disperse as a produce contaminant

y=1, n=-1

n

7.04

Propagules adapted to wind dispersal

y=1, n=-1

7.05

Propagules water dispersed

y=1, n=-1

n

7.06

Propagules bird dispersed

y=1, n=-1

n

7.07

Propagules dispersed by other animals (externally)

y=1, n=-1

n

7.08

Propagules survive passage through the gut

y=1, n=-1

y

8.01

Prolific seed production (>1000/m2)

y=1, n=-1

n

8.02

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

y=1, n=-1

y

8.03

Well controlled by herbicides

y=-1, n=1

y

8.04

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

y=1, n=-1

y

8.05

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

y=-1, n=1

Total score:

18

Source

Notes

1.01

No evidence.

1.02

(1)Native to Africa and widely naturalized in tropics and subtropics. (2)From Zaire and Kenya the grass has been introduced widely in tropical areas, especially Costa Rica, Colombia, Hawaii, Australia and southern Africa. 

(1)http://www.ars-grin.gov/cgi-bin/npgs/html/taxon.pl?27178 (2)http://www.fao.org/ag/AGP/AGPC/doc/Gbase/DATA/Pf000298.htm

1.03

No evidence.

2.01

Native to Africa and widely naturalized in tropics and subtropics.

http://www.ars-grin.gov/cgi-bin/npgs/html/taxon.pl?27178

2.02

2.03

(1)Elevation: between 0 and 328 feet in California. (2)It is found on all major islands from 500-2,000 m in dry and mesic habitats. It will also invade wet environments when the forest is disturbed. (3)Sea-level to 3 500 m and latitude range is mean 27°N and S

(1)http://www.calflora.org/cgi/calflora_query?one=T&where-calrecnum=6132 (2)http://www.botany.hawaii.edu/faculty/cw_smith/pen_cla.htm (3)http://www.fao.org/ag/AGP/AGPC/doc/Gbase/DATA/Pf000298.htm

2.04

Native to Africa and widely naturalized in tropics and subtropics.

http://www.ars-grin.gov/cgi-bin/npgs/html/taxon.pl?27178

2.05

Native to Africa and widely naturalized in tropics and subtropics.

http://www.ars-grin.gov/cgi-bin/npgs/html/taxon.pl?27178

3.01

Naturalized and a noxious weed in the U.S.

http://plants.usda.gov/cgi_bin/topics.cgi

3.02

(1) 'A toublesome weed in orchards and gardens in southern California.' (2)It will also invade wet environments when the forest is disturbed.

(1)Hitchcock, A.S. 1950. Manual of the grasses of the United States. United States government printing office Washington. (2)http://www.botany.hawaii.edu/faculty/cw_smith/pen_cla.htm

3.03

(1)It is a serious weed in Costa Rica, Kenya, Peru, Uganda and Uruguay. It is a principal weed in Australia, Brazil, Columbia, Hawaii, India, New Zealand and Tanzania. (2)It is an agricultural weed in California. (3)P. clandestinum was identified for the first time in Chile in Apr. 1985. It is invading fruit orchards, vineyards and pastures in the coastal areas and in the irrigated fields of Copiapó (Region III), Elqui and Limarí (Region IV). It has also been found in some localities of Valparaíso (Region V) and around Melipilla (Metropolitan Region). (4)Listed on the Federal and California state noxious weed list. 5) weed of potatoes

(1) Holm, L, Pancho, J.V.,Herberger,J.P. and Plucknett, D.L. 1979. A geogrpahical atlas of world weeds. John Wiley and sons. New York. (2)http://www.calflora.org/cgi/calflora_query?one=T&where-calrecnum=6132 (3)Nitsche M., J. . 1986. Kikuyo grass (Pennisetum clandestinum Hochst ex Chiov.) a new weed in Chile. El kikuyo (Pennisetum clandestinum Hochst ex Chiov.) maleza nueva para Chile. Agricultura Técnica Vol.46, No.2, pp.225-226.
4)http://elib.cs.berkeley.edu/cgi/calflora_query?special=calflora&where-calrecnum=6132&one=T 5)http://www.kari.org/Narp/dfid%20theme%205/177e.html

3.04

(1)It is a serious pest in forests…shading out shrubs and herbs --(statement is of unknown orign or basis. This species can occur in large forest gaps and edges, requires high light and is best classified as a disturbance weed (3.02))

(1)http://www.hear.org/pier/pecla.htm

3.05

P. macroururm, P. pedicellatum, P. polystachyon are listed on the federal noxious weed list.

http://plants.usda.gov/cgi_bin/topics.cgi

4.01

No evidence of spines, thorns or burrs.

Wagner,W. L., D. R. Herbst & S. H. Sohmer. 1990. Manual of flowering plants of Hawaii.University of Hawaii at Press. Honolulu.

4.02

(1)The grass produces allelopathic substances which may have a detrimental effect on the persistence of mixed pastures in which kikuyu is a component. (2)It is a serious pest in forests because, apart from shading out shrubs and herbs, it releases allelopathic substances which kill almost all other species in the vicinity

(1) Marais, J. P. 2001. Factors affecting the nutritive value of kikuyu grass (Pennisetum clandestinum ) - a review. Tropical Grasslands Vol.35, No.2, pp.65-84.
(2)http://www.botany.hawaii.edu/faculty/cw_smith/pen_cla.htm

4.03

No evidence.

4.04

Palatability is very high. 

http://www.fao.org/ag/AGP/AGPC/doc/Gbase/DATA/Pf000298.htm

4.05

USUALLY NOT TOXIC. FUNGAL ENDOPHYTE MAYBE (1)'In the late summer and autumn of 1980 kikuyu poisoning of cattle was diagnosed on 9 farms in New South Wales resulting in 213 deaths among 1370 cattle at risk.' 'Evidence from the isolation of pasture fungi has not suggested a mycotic cause of kikuyu poisoning. The epidemiological evidence of lush growth following drought-breaking rains suggests that a plant toxin may be involved.' (2) However, under certain conditions kikuyugrass can accumulate high levels of nitrates and soluble oxalates that are toxic to livestock when ingested.

(1)Wong, PTW, Roth, IJ snf Jackson, ARB. 1987. Kikuyu poisoning of cattle in New South Wales and its relationship to pasture fung on Kikuyu grass (Pennisetum clandestinum). Australian Veterinary Journal Vol 64 no 8. 229-232 (2)http://pi.cdfa.ca.gov/weedinfo/PENNISET2.html

4.06

(1)This website lists 59 species of fungi that are found on P. clandestinum (don’t know whether they are economically important.) (2) '...C. lunata [Cochliobolus lunatus ] was identified from P. clandestinum seed samples from the USA. Pathogenicity was confirmed.' (3)A phycomycete resembling a species of Achlya was isolated from leaves of kikuyugrass (Pennisetum clandestinum) in Australia. Leaves become uniformly yellow with brown flecking. Roots become yellowish brown and rotted. No information is available concerning its pathogenicity to pearl millet or other Pennisetum species. (4)Larvae of the pasture scarab beetle (Rhopea magnicornis), Tarsonemus mites and soldier fly (Atlermetapomia rubiceps) have caused temporary damage to Kikuyu in Australia, but the effects are short-lived (Mears, 1970). In Hawaii, the hunting bull bug (Sphenophorus vestitis) and grass webworm (Herpetogramma licarsicalis) cause damage (Plucknett, 1970). [I found none of the above pests and pathogens to be of economic importan

(3)http://www.ars.usda.gov/is/np/pearlmillet/qky.htm (4)http://www.fao.org/ag/AGP/AGPC/doc/Gbase/DATA/Pf000298.htm

4.07

no evidence

4.08

(1)Where Kikuyu thrives there should be little fire risk, but in dry times the green top growth may hide a dry basal layer of dead leaves which can support a creeping fire. (2)It burns very slowly and generally retards fire.

(1)http://www.botany.hawaii.edu/faculty/cw_smith/pen_cla.htm (2)http://www.fao.org/ag/AGP/AGPC/doc/Gbase/DATA/Pf000298.htm

4.09

(1)Can tolerate light shade. (2)Kikuyu does not grow well in shade.

(1)http://pi.cdfa.ca.gov/weedinfo/PENNISET2.html (2)http://www.fao.org/ag/AGP/AGPC/doc/Gbase/DATA/Pf000298.htm

4.1

(1)Can grown on most soil types. (2)Its natural occurrence is mainly on deep latosolic soils of good fertility, and it has quickly adapted to similar soils elsewhere. It also thrives on alluvial soils and on moist, sandy soils where the fertility has been raised by animal excrete or mineral fertilizer.

(1)http://pi.cdfa.ca.gov/weedinfo/PENNISET2.html (2)http://www.fao.org/ag/AGP/AGPC/doc/Gbase/DATA/Pf000298.htm

4.11

It is a perennial grass and not a vine.

4.12

Forms dense, tall stands

http://www.botany.hawaii.edu/faculty/cw_smith/pen_cla.htm

5.01

5.02

Perennial grass.

http://plants.usda.gov/cgi_bin/topics.cgi

5.03

5.04

6.01

No evidence.

6.02

'In Queensland, 60 percent germinable seed of 93 percent purity ..'.

http://www.fao.org/ag/AGP/AGPC/doc/Gbase/DATA/Pf000298.htm

6.03

No information.

6.04

Apomictic (asexual reproduction where embryos develop without fertilization) and to a smaller degree, out-crossing. Pollination is required for apomictic seed development

http://pi.cdfa.ca.gov/weedinfo/PENNISET2.html

6.05

Probably not - flower morphology does not reveal any adaptation to a specialist pollinator. Most grasses are wind-pollinated.

6.06

(1)The grass reproduces vegetatively and by means of seed (2)Produces seed. Pieces of rhizome break off and sprout.

(1) Marais-J-P {a}. 2001.Factors affecting the nutritive value of kikuyu grass (Pennisetum clandestinum): A review. Tropical-Grasslands. 35 (2): 65-84. (2)http://www.boprc.govt.nz/www/green/weed72.htm

6.07

Fast-growing herbaceous grass.

7.01

1) accientally spread by "dumping" of plant fragments

1) http://www.bushcare.org.au/WeedControl.htm

7.02

P. clandestinum has pasture and ornamental value - it is cultivated as a pasture and lawn grass and hence likely to be introduced intentionally.

Russell, GE, Watson, L et al. 1991. Grasses of Southern Africa. National Botanical gardens. South Africa.

7.03

The large seed (2 mm long) is dark brown, flat or ellipsoidal with a prominent style - hence less likely to be introduces as a produce contaminant. Rarely seeds.

http://www.ipm.ucdavis.edu/PMG/WEEDS/kikuyugrass.html

7.04

No obvious structural adaptations, but spikels could be carried by wind.

7.05

7.06

7.07

Propagules do not have any means of attachment.

7.08

(1)'seeds of kikuyu eaten during grazing are passed out intact in the dung which provides an excellent medium for establishment. By this means kikuyu can be easily introduced into other pastures by grazing animals.' (2)Seeds may be long-lived under field conditions and can survive ingestion by sheep.

(1)Quinla, T. J.,Shaw K. A., and Edgley, WHR. 1975. Kikuyu grass. Queensland Agricultural journal Vol 101(6):737-749. (2)http://pi.cdfa.ca.gov/weedinfo/PENNISET2.html

8.01

The seeds are 1/8 inch long and are shiny dark brown. (2)Caryposis 2.5-3mm long. (3)The large seed (2 mm long) is dark brown, flat or ellipsoidal with a prominent style. (4)up to 500 kg/ha from established swards - with about 40,000 seeds per Kg. (Rarely seeds)

(3)http://www.ipm.ucdavis.edu/PMG/WEEDS/kikuyugrass.html (4)http://www.fao.org/ag/AGP/AGPC/doc/Gbase/DATA/Pf000298.htm

8.02

Seeds may be long-lived under field conditions and can survive ingestion by sheep. Seedlings typically emerge from soil depths up to ~ 6 cm (2.25 in).

http://pi.cdfa.ca.gov/weedinfo/PENNISET2.html (3)http://www.fao.org/ag/AGP/AGPC/doc/Gbase/DATA/Pf000298.htm

8.03

(1) 'Chemical Control
Spray with Roundup (without Pulse), or Gallant. Best results spraying new growth, spring and autumn. Spot spraying of regrowth is necessary.
(i) Roundup. Use of Pulse when spraying kikuyu may cause poor results.
Rate - Handgun 1 liter Roundup/100 liters water. Knapsack 100 mils Roundup/10 liters water.
(ii) Gallant (Controls grasses and some sedges; ineffective on broadleaf spp.)
Rate - Handgun 500 mls Gallant/100 liters water. Knapsack 50 mls Gallant/10 liters water. (2)The grass can be eradicated by spraying with 0.5% glyphosate (Gardner and Kageler 1983) or Dalapon (Hosaka 1958).
(3)Treatment with MSMA, triclopyr, and quinclorac did not control kikuyugrass as single applications, but when applied at 4- to 5-wk intervals over a 5-mo period, kikuyugrass was reduced. Sequential applications of two-way combinations of these herbicides in 1991 resulted in reductions of kikuyugrass from 80% to less than 1% of the sward.

(1) http://www.boprc.govt.nz/www/green/weed72.htm (2)http://www.botany.hawaii.edu/faculty/cw_smith/pen_cla.htm (3)Cudney-David-W {a}; Downer-James-A; Gibeault-Victor-A; Henry-J-Michael; Reints-John-S. 1993. Kikuyugrass (Pennisetum clandestinum) management in turf. Weed-Technology. 7 (1) 180-184. (4)Rozanski, A. 1982. Elimination of Kikuyu grass (Pennisetum clandestinum (L.) Rich. Hochst.) with dalapon and glyphosate. Erradicação do capim-quicuio (Pennisetum clandestinum (L.) Rich. Hochst.) com dalapon e glyphosate. Abstracts of the XIV Brazilian congress on herbicides and herbaceous weeds (SBHED) and the VI congress of the Latin American Weed Association (ALAM), Campinas pp.169-170. (5)Londono, W.; Cruz K., R. G. 1976. Evaluation of five herbicides for control of Kikuyu grass (Pennisetum clandestinum Hochst). Evaluacion de cinco herbicidas en el control de "kikuyo" (Pennisetum clandestinum Hochst) o

8.04

Where Kikuyu thrives there should be little fire risk, but in dry times the green top growth may hide a dry basal layer of dead leaves which can support a creeping fire. The plants soon recover. 

http://www.fao.org/ag/AGP/AGPC/doc/Gbase/DATA/Pf000298.htm

8.05

Two insect pests, Sphenophorus ventus vestitus and Herpetogramma licarsicalis plus one rust fungus are present in Hawai‘i

http://www.hear.org/pier/pecla.htm