Cenchrus longispinus Risk – California Invasive Plant Council

Created by: Kristina Wolf
Created on: Monday, Apr 11th, 2016

Evaluation Summary

Summary:

General Evaluation Information

Date of Evaluation:

April 11, 2016

Evaluation Time (hrs):

3 Hours

Evaluation Status:

Completed

Plant Information

Plant:

Cenchrus longispinus

Plant Material:

If the plant is a cultivar, and if the cultivar's behavior differs from its parent's (behavior), explain how:

Regional Information

Region Name:

California

Climate Matching Map

These maps were built using a toolkit created in collaboration between GreenInfo Network, PlantRight, Cal-IPC, and Agricultural Sustainability Institute at UC Davis.

Link to Climate Matching Map:

Climate Matching Maps PDF:

Invasive History and Climate Matching

1. Has the species (or cultivar or variety, if applicable; applies to subsequent "species" questions) become naturalized where it is not native?

Yes or No:

Yes

Points:

Confidence Level:

Medium

Answer / Justification:

It has formed naturalized populations in western Europe, Africa, and Australia (Grasses of Iowa). Naturalized in California (Calflora).

Reference(s):

Iowa State University (0). Grasses of Iowa.

Calflora (2015). Calflora.

2. Is the species (or cultivar or variety) noted as being naturalized in the US or world in a similar climate?

Yes or No:

Yes

Points:

Confidence Level:

Medium

Answer / Justification:

It has formed naturalized populations in western Europe, Africa, and Australia (Grasses of Iowa). Naturalized in California (Calflora).

Reference(s):

Iowa State University (0). Grasses of Iowa.

Calflora (2015). Calflora.

3. Is the species (or cultivar or variety) noted as being invasive in the U.S. or world?

Yes or No:

Yes

Points:

Confidence Level:

High

Answer / Justification:

Longspine sandbur is a troublesome weed in many irrigated crops in the westem United States (Time of emergence and seed production of longspine sandbur (Cenchrus longispinus) and puncturevine (Tribulus terrestris)). It is a noxious weed in Europe, Australia and New Zealand where it was introduced (Wikipedia). Considered a noxious weed in California and Washington (Go Botany).

Reference(s):

Boydston, R. A. (1990). Time of emergence and seed production of longspine sandbur (Cenchrus longispinus) and puncturevine (Tribulus terrestris). Weed Science. 16–21.

Wikipedia (2015). Wikipedia.

New England Wild Flower Society (2016). Go Botany.

4. Is the species (or cultivar or variety) noted as being invasive in the US or world in a similar climate?

Yes or No:

Yes

Points:

Confidence Level:

High

Answer / Justification:

It is a noxious weed in Europe, Australia and New Zealand where it was introduced (Wikipedia). Considered a noxious weed in California and Washington (Go Botany; CDFA).

Reference(s):

Wikipedia (2015). Wikipedia.

New England Wild Flower Society (2016). Go Botany.

CDFA (0). CDFA's Division of Plant Health's Pest Ratings and Proposals.

5. Are other species of the same genus (or closely related genera) invasive in a similar climate?

Yes or No:

Yes

Points:

Confidence Level:

Very High

Answer / Justification:

Cenchrus echinatus is considered invasive in California; Similar exotic species: Cenchrus ciliaris (FloraBase: The Western Australia Flora). Cenchrus spinifex is an aggressive invader in Arizona (Invasive Plants and Weeds of the National Forests and Grasslands in the Southwestern Region 2nd edition). C. echinatus is considered a noxious weed in Arizona (USDA-NRCS Plants Database), Australia (Wikipedia). It can grow in many habitats and is found in dry and moist regions in rainfed and irrigated crops and has been reported as a weed of 18 crops in 35 countries, mostly in cereals, pulses, vineyards, plantation crops and pastures. C. echinatus occurs as a weed in many crops worldwide. It is common in cultivated fields, pastures, fallows, orchards, vineyards, coffee, vegetables, bananas, coconuts and lawns, where it can withstand repeated defoliation. It can be found along roadsides and beaches, in open ground and waste places. Crops competing for nutrients with C. echinatus typically have smaller leaf areas and lower growth rates and yields (CABI; Crop Science). Invasive in many regions throughout the world, especially tropical regions, and Australia, China, Japan, and New Zealand (PIER).

Reference(s):

Coleman, H., Brown K., & Bettink K. (2014). FloraBase: The Western Australia Flora.

United States Department of Agriculture, Forest Service (2013). Invasive Plants and Weeds of the National Forests and Grasslands in the Southwestern Region 2nd edition.

[Anonymous] (2014). USDA-NRCS Plants Database.

Bayer CropScience AG (2016). Crop Science.

[Anonymous] (2007). CABI Invasive Species Compendium.

PIER (0). Pacific Island Ecosystems at Risk (PIER) Risk Assessments.

Wikipedia (2015). Wikipedia.

6. Is the species (or cultivar or variety) found predominately in a climate matching the region of concern?

Yes or No:

Yes

Points:

Confidence Level:

High

Answer / Justification:

Native to central and eastern U.S. (Jepson). Present in central U.S., Mediterranean region and other parts of Europe, central Australia (CABI).

Reference(s):

Jepson Flora Project (2015). The Jepson Herbarium Online.

[Anonymous] (2007). CABI Invasive Species Compendium.

Impact on Native Plants and Animals

7. Does this plant displace native plants and dominate (overtop or smother) the plant community in areas where it has established?

Yes or No:

Points:

Confidence Level:

Medium

Answer / Justification:

Plants often form large mats and can grow to 2 feet (0.6 m) in length (UC IPM). Can spread rapidly and has a tendency to develop into dense infestations in favourable conditions (NSW Weedwise). Given the mat-forming tendencies of this species, it is likely that native plants could be displaced in areas of severe infestation, but an exhaustive Google/Google Scholar search did not reveal evidence of this, and this defaults to a "no" answer.

Reference(s):

Regents of the University of Calfornia (2014). University of California Agriculture and Natural Resources Statewide Integrated Pest Management Program (UC IPM).

NSW Department of Primary Industries, Primary Industries Agriculture, New South Wales Department of Primary Industries (2014). NSW Weedwise.

8. Is the plant noted as promoting fire and/or changing fire regimes?

Yes or No:

Points:

Confidence Level:

Medium

Answer / Justification:

An exhaustive Google/Google Scholar search did not reveal any evidence of fire promotion or changes to fire regimes, and this defaults to a "no" answer.

Reference(s):

9. Is the plant a health risk to humans or animals/fish? Has the species been noted as impacting grazing systems?

Yes or No:

Yes

Points:

Confidence Level:

Very High

Answer / Justification:

Immature sandburs provide good forage for livestock. However, when they mature they develop fruit with stiff spines that can injure the mouths of animals and the hands and feet of people (UC IPM). Mature burrs cause a range of problems such as: injury to stock causing swellings and ulcers in the mouth; injury to people and dogs; clinging to wool and penetrating the skin of stock, reducing the value of both; shearing difficulties, which often attracts penalty rates as working with contaminated wool requires leather gloves and/or aprons; inconvenience and discomfort to workers in irrigated crops such as vegetables, vines and citrus, and; contamination of dried fruit and hay (NSW Weedwise). The weed is also a contaminant in dried fruit and may infest lucerne hay (Agriculture Victoria).

Reference(s):

Regents of the University of Calfornia (2014). University of California Agriculture and Natural Resources Statewide Integrated Pest Management Program (UC IPM).

NSW Department of Primary Industries, Primary Industries Agriculture, New South Wales Department of Primary Industries (2014). NSW Weedwise.

Department of Environment, Victoria Primary Industries (2015). Agriculture Victoria (VRO).

10. Does the plant produce impenetrable thickets, blocking or slowing movement of animals, livestock, or humans?

Yes or No:

Yes

Points:

Confidence Level:

High

Answer / Justification:

Plants often form large mats and can grow to 2 feet (0.6 m) in length (UC IPM). The spines of spiny burr grass can easily puncture the skin of animals and has the potential to injure fauna. Spines may also injure humans.Burrs are present for much of the year. The plant does not pose any restrictions to human movement except when burrs are present (Agriculture Victoria).

Reference(s):

Regents of the University of Calfornia (2014). University of California Agriculture and Natural Resources Statewide Integrated Pest Management Program (UC IPM).

Department of Environment, Victoria Primary Industries (2015). Agriculture Victoria (VRO).

Reproductive Strategies

11. Does this species (or cultivar or variety) reproduce and spread vegetatively?

Yes or No:

Points:

Confidence Level:

Medium

Answer / Justification:

An exhaustive Google/Google Scholar search did not reveal any evidence of reproduction by asexual means, and this defaults to a "no" answer.

Reference(s):

12. If naturally detached fragments from this plant are capable of producing new plants, is this a common method of reproduction for the plant?

Yes or No:

Points:

Confidence Level:

Medium

Answer / Justification:

An exhaustive Google/Google Scholar search did not reveal any evidence of reproduction by asexual means or fragmentation, and this is a terrestrial grass that is unlikely to fragment, so this defaults to a "no" answer.

Reference(s):

13. Does the species (or cultivar or variety) commonly produce viable seed?

Yes or No:

Yes

Points:

Confidence Level:

High

Answer / Justification:

Reproduces by seed (NSW Weedwise; UC IPM).

Reference(s):

NSW Department of Primary Industries, Primary Industries Agriculture, New South Wales Department of Primary Industries (2014). NSW Weedwise.

Regents of the University of Calfornia (2014). University of California Agriculture and Natural Resources Statewide Integrated Pest Management Program (UC IPM).

14. Does this plant produce copious viable seeds each year (> 1000)?

Yes or No:

Yes

Points:

Confidence Level:

Very High

Answer / Justification:

Can produce over 5600 burs per plant. Assuming an average of two seed per bur, plants produced approximately 133,000, 49,000, 5,000, and 40 seed per plant from May, June, July, and August plantings in 1986, respectively (Time of emergence and seed production of longspine sandbur (Cenchrus longispinus) and puncturevine (Tribulus terrestris)).

Reference(s):

Boydston, R. A. (1990). Time of emergence and seed production of longspine sandbur (Cenchrus longispinus) and puncturevine (Tribulus terrestris). Weed Science. 16–21.

15. Is there significant germination (>25%) of seeds the next growing season, with no requirement of an infrequent environmental condition for seeds to germinate (i.e. fire) or long dormancy period?

Yes or No:

Yes

Points:

Confidence Level:

Very High

Answer / Justification:

Fall-planted longspine sandbur began to emerge in April, peaked in late April or May, and continued at low levels through October. During the first year after seeding, 98% of the total seedlings emerged prior to June. Longspine sandbur germinates more readily from cultivated sites than from undisturbed sites, and (Time of emergence and seed production of longspine sandbur (Cenchrus longispinus) and puncturevine (Tribulus terrestris)). 84% of seasonal emergence occurred within a 4 week period from May 25 to June 15, but continued into August (Longspine sandbur (Cenchrus longispinus) ecology and interference in irrigated corn (Zea mays)).

Reference(s):

Boydston, R. A. (1990). Time of emergence and seed production of longspine sandbur (Cenchrus longispinus) and puncturevine (Tribulus terrestris). Weed Science. 16–21.

Anderson, R. L. (1997). Longspine sandbur (Cenchrus longispinus) ecology and interference in irrigated corn (Zea mays). Weed technology. 667–671.

16. Does this plant produce viable seed within the first three years (for an herbaceous species) to five years (for a woody species) after germination?

Yes or No:

Yes

Points:

Confidence Level:

Very High

Answer / Justification:

Annual plant (Time of emergence and seed production of longspine sandbur (Cenchrus longispinus) and puncturevine (Tribulus terrestris)).

Reference(s):

Boydston, R. A. (1990). Time of emergence and seed production of longspine sandbur (Cenchrus longispinus) and puncturevine (Tribulus terrestris). Weed Science. 16–21.

17. Does this plant continuously produce seed for >3 months each year or does seed production occur more than once a year?

Yes or No:

Points:

Confidence Level:

High

Answer / Justification:

Flowering takes place from July through September (UC IPM; Calflora).

Reference(s):

Regents of the University of Calfornia (2014). University of California Agriculture and Natural Resources Statewide Integrated Pest Management Program (UC IPM).

Calflora (2015). Calflora.

Dispersal

18. Are the plant’s propagules frequently dispersed long distance (>100 m) by mammals or birds or via domestic animals?

Yes or No:

Yes

Points:

Confidence Level:

High

Answer / Justification:

Burs disperse in many ways such as by clinging to animals, shoes, clothing, tires, machinery, and floating on water (UC IPM).

Reference(s):

Regents of the University of Calfornia (2014). University of California Agriculture and Natural Resources Statewide Integrated Pest Management Program (UC IPM).

19. Are the plant’s propagules frequently dispersed long distance (>100 m) by wind or water?

Yes or No:

Yes

Points:

Confidence Level:

Medium

Answer / Justification:

Burs disperse in many ways such as by clinging to animals, shoes, clothing, tires, machinery, and floating on water (UC IPM).

Reference(s):

Regents of the University of Calfornia (2014). University of California Agriculture and Natural Resources Statewide Integrated Pest Management Program (UC IPM).

20. Are the plant’s propagules frequently dispersed via contaminated seed (agriculture or wildflower packets), equipment, vehicles, boats or clothing/shoes?

Yes or No:

Yes

Points:

Confidence Level:

Very High

Answer / Justification:

Burs disperse in many ways such as by clinging to animals, shoes, clothing, tires, machinery, and floating on water (UC IPM). The weed is also a contaminant in dried fruit and may infest lucerne hay (Agriculture Victoria).

Reference(s):

Regents of the University of Calfornia (2014). University of California Agriculture and Natural Resources Statewide Integrated Pest Management Program (UC IPM).

Department of Environment, Victoria Primary Industries (2015). Agriculture Victoria (VRO).

Evaluation Notes

CDFA source added for Q4; confidence level changed to High. Nothing else changed. Reviewed by Elizabeth Brusati (edbrusati@cal-ipc.org, Cal-IPC).

Websites consulted for this screen included:

CDFA: https://www.cdfa.ca.gov/plant/ipc/encycloweedia/weedinfo/winfo_table-sci...

Tropicos: http://www.tropicos.org/Name/25511770; GBIF: no record for this species; UC IPM: http://www.ipm.ucdavis.edu/PMG/WEEDS/longspine_sandbur.html; ARS GRIN: https://npgsweb.ars-grin.gov/gringlobal/taxonomydetail.aspx?103625; USU Herbarium: http://www.herbarium.usu.edu/webmanual/info.asp?name=Cenchrus_longispinu... NWCB: http://www.nwcb.wa.gov/detail.asp?weed=24; USDA PLANTS: http://plants.usda.gov/core/profile?symbol=CELO3; Anderson 1997: http://www.ars.usda.gov/SP2UserFiles/Place/30100000/1990-1999documents/3... Wikipedia: https://en.wikipedia.org/wiki/Cenchrus_longispinus; NSW Weeds: http://weeds.dpi.nsw.gov.au/Weeds/Details/131; Calflora: http://www.calflora.org/cgi-bin/species_query.cgi?where-calrecnum=1842; Jepson: http://herbaria4.herb.berkeley.edu/eflora_display.php?tid=18557; Agriculture Victoria: http://agriculture.vic.gov.au/agriculture/pests-diseases-and-weeds/weeds... http://vro.agriculture.vic.gov.au/dpi/vro/vrosite.nsf/pages/invasive_spi... Go Botany: https://gobotany.newenglandwild.org/species/cenchrus/longispinus/; Iowa State University: http://www.eeob.iastate.edu/research/IowaGrasses/speciespages/CenchLongi...