Tag Archives: Asteraceae

Gymnocoronis spilanthoides | Senegal tea plant

5399455-SenegalTeaPlant-by-Robert-VidekiDoronicumKft-Bugwood
California Pest Rating for
Family: Asteraceae
Gymnocoronis spilanthoides – Senegal tea plant
Synonym- Alomia splanthoides (D. Don ex Hook & Arnott)
Pest Rating: A |  Proposed Seed Rating: P

 


PEST RATING PROFILE
Initiating Event:

This plant was recently intercepted by a county dog team in a USPS shipment from Arizona. The species has been listed as noxious by Australia due to its invasion potential in wet habitats and is under investigation by USDA APHIS.

History & Status:

Senegal tea plant is a long lived aquatic, broadleaved and herbaceous perennial plant that grows on damp ground or in shallowly submerged soil. It forms a rounded clump or a tangled mass of vegetation along waterways. Senegal tea plant is a weed of wetter tropical, sub-tropical and warm temperate environments. It is particularly problematic along streams, around lakes and dams, in swamps, wetlands and along drains and channels. It has been introduced into Australia and India by the Aquarium industry, as this plant is sometimes used for aquaria2.

Senegal tea plant is native to South America (Brazil, Peru, Argentina, Paraguay and Uruguay) and Mexico3. It grows very rapidly, up to 15 cm per week and its floating mats cover water bodies, block drainage channels and degrade natural wetlands2. The Weed Science Society of America (WSA) has noted that it is one of the 16 weeds not yet present in the United States that poses the greatest potential threat to its ecosystems2.

Official Control: Senegal tea plant is recognized as a harmful weed in the Republic of Korea6. It has been classified as a noxious weed in New Zealand and in Australia. It has been put on North American Plant Protection Organization’s (NAPPO) Phytosanitary Alert List. Importation of Senegal tea plant to Australia and New Zealand is not permitted because of the risk of further spread3. It has not yet established in California.

California Distribution: Senegal tea plant is not found spontaneously in California at this time.

California Interceptions: State exterior quarantine inspectors have intercepted this plant once in a shipment from Arizona10. It has not been found in the natural environment of California.

United States Distribution: Senegal tea plant is present in the United State aquarium trade and is sold online in the U.S.7. It has not been found in the natural environment in the United States.

International Range: Senegal tea plant is a native to South America (Brazil, Peru, Argentina, Paraguay and Uruguay) and Mexico. It is naturalized in Senegal, Hungary and parts of Asia, South America and Oceania. Recently, it is reported to be naturalized in irrigation canals and rice fields in Italy1.

This risk Senegal tea plant would pose to California is evaluated below.

Consequences of Introduction:

1) Climate/Host Interaction: Risk is High (3). Senegal tea plant grows in humid tropics, subtropics and warm temperate regions where it forms dense floating mats, rooted in damp soil. It grows over the surface of slow moving or stationary water bodies, in wet marshy soils, wetlands and in degraded waterways. California’s Mediterranean climate with rainy winters and dry summers is similar to climate in Western Australia where this weed is recognized as invasive2. Senegal tea plant can become established if it is introduced to California through aquarium and nursery trade.

Score: 3

Evaluate if the pest would have suitable hosts and climate to establish in California.

Low (1) Not likely to establish in California; or likely to establish in very limited areas.

Medium (2) may be able to establish in a larger but limited part of California.

High (3) likely to establish a widespread distribution in California.

2) Known Pest Host Range: Risk is High (3) .Senegal tea plant does not require any one host, but grows where ecological conditions are favorable. It has the potential to grow in California due to its affinity to grow in regions with 20-100 inch precipitation and warmer summers7.

Score: 3

Evaluate the host range of the pest.

Low (1) has a very limited host range.

Medium (2) has a moderate host range.

High (3) has a wide host range.

3) Pest Dispersal Potential: Risk is High (3). Senegal tea plant reproduces by seeds and vegetative means. It produces roots at the joints along the stems enabling new plants to grow from stems fragments. Seeds and stem fragments spread mainly by water. Seeds can accidentally spread in mud attached to the feet of animals. Stem fragments can also be spread easily by transport and machinery (e.g. boats, trailers, and lawnmowers). Another means of introduction to new areas is through unwise disposal (dumping) of aquarium plants in fresh water2, 4, 8.

Score: 3

Evaluate the natural and artificial dispersal potential of the pest.

Low (1) does not have high reproductive or dispersal potential.

Medium (2) has either high reproductive or dispersal potential.

High (3) has both high reproduction and dispersal potential.

4) Economic Impact: Risk is Medium (2). Senegal tea plant infestation can cause blockage of water ways and drainage channels leading to increased damage caused by flooding. When large amount of this plant die off and rot under water, the quality of water is compromised6. This plant is hard to kill, as herbicides can kill only the upper parts of the plant and plant parts beneath water are not killed. Below water plant material and silt can be removed by heavy machines3. Senegal tea plant is a rarely encountered aquarium plant and some plants from Southeast Asia are sold in California. Given the small number of plants involved, the income generated from such sales on an annual basis are unlikely to be significant, much less approaching the potential control costs following the successful invasion of California by this plant.

Score: 2

Evaluate the likely economic impacts of the pest to California using the criteria below.

A. The pest could lower crop yield.

B. The pest could lower crop value (includes increasing crop production costs).

C. The pest could trigger the loss of markets (includes quarantines).

D. The pest could negatively change normal cultural practices.

E. The pest can vector, or is vectored, by another pestiferous organism.

F. The organism is injurious or poisonous to agriculturally important animals.

G. The organism can interfere with the delivery or supply of water for agricultural uses.

Score the pest for Environmental Impact:

Low (1) causes 0 or 1 of these impacts.

Medium (2) causes 2 of these impacts.

High (3) causes 3 or more of these impacts.

5) Environmental Impact: Risk is High (3). Senegal tea plant can easily invade and degrade natural wetland ecosystems and waterways. It competes strongly with slower growing native plants and can eventually replace them. This in turn can affect wetland birds and animals which are dependent on these native plants for food and shelter. Senegal tea plant poses a significant threat to entire wetland ecosystems in Australia. This weed can quickly takes over wetlands and can detract from their environmental value, natural beauty and recreation potential. Since it’s found mainly in water, the herbicides used for control can potentially impact non target plants and animals4,8.

Score: 3

Evaluate the environmental impact of the pest on California using the criteria below:

A. The pest could have a significant environmental impact such as lowering biodiversity, disrupting natural communities, or changing ecosystem processes.

B. The pest could directly affect threatened or endangered species.

C. The pest could impact threatened or endangered species by disrupting critical habitats.

D. The pest could trigger additional official or private treatment programs.

E. The pest significantly impacts cultural practices, home/urban gardening or ornamental plantings.

   Score the pest for Environmental Impact:

Low (1) causes none of the above to occur.

Medium (2) causes one of the above to occur.

High (3) causes two or more of the above to occur.

Consequences of Introduction to California for Senegal tea plant:

Add up the total score and include it here. (14)

Low = 5-8 points

Medium = 9-12 points

High = 13-15 points

6) Post Entry Distribution and Survey Information: Only official records identified by a taxonomic expert and supported by voucher specimens deposited in natural history collections should be considered. Pest incursions that have been eradicated, are under eradication, or have been delimited with no further detections should not be included.

Score: 0

Not established (0) Pest never detected in California, or known only from incursions.

Low (-1) Pest has a localized distribution in California, or is established in one suitable climate/host area (region).

Medium (-2) Pest is widespread in California but not fully established in the endangered area, or pest established in two contiguous suitable climate/host areas.

High (-3) Pest has fully established in the endangered area, or pest is reported in more than two contiguous or non-contiguous suitable climate/host areas.

Final Score:

The final score is the consequences of introduction score minus the post entry distribution and survey information. Final score: 14

Uncertainty:  

California is suitable for the establishment of Senegal tea plant. However, the exact habitat for its establishment is not yet known. Based on the USDA APHIS weed risk assessment, this plant is in the aquarium trade and is cultivated in the United States (Anonymous, 2012; Extra Plant, 2012). This plant has the ability of rapid growth and spread in places with warm summers, rainy winter’s and the Marine West Coast.

Conclusion and Rating Justification:

Senegal tea plant is recognized as high alert weed in Australia and New Zealand. The European and Mediterranean Plant Protection Organization (EPPO) added this weed to its alert list in 2009.   It qualifies for an A rating, as it has invaded habitats in Australia that are similar to those found in California.

References:

1Ardenghi, N. M. G., G. Barcheri, C. Ballerini, P. Cauzzi, and F. Guzzon. 2016. Gymnocoronis spilanthoides (Asteraceae, Eupatorieae), a new naturalized and potentially invasive aquatic alien in S Europe. Willdenowia 46:265-273. Last accessed 11/01/2016
http://www.bioone.org/doi/pdf/10.3372/wi.46.46208.

2Invasive species compendium; Assessed date: 10/12/2016
http://www.cabi.org/isc/datasheet/26246

3Weed Management Guide: Senegal Tea Plant- Gymnocoronis spilanthoides; Assessed date:10-12-2016
https://www.environment.gov.au/biodiversity/invasive/weeds/publications/guidelines/alert/pubs/g-spilanthoides.pdf

4Environmental weeds of Australia for Biosecurity Queensland: Gymnocoronis spilanthoides; Assessed Date:10-12-2016
http://keyserver.lucidcentral.org/weeds/data/media/Html/gymnocoronis_spilanthoides.htm

5European and Mediterranean Plant protection Organization: Assessed date:10/12/2016
https://www.eppo.int/INVASIVE_PLANTS/observation_list/Gymnocoronis_spilanthoides.htm

6USDA PCIT PeXD; Assessed Date: 10/12/2016
https://pcit.aphis.usda.gov/PExD/faces/PExDReport.jsp

7Weed Risk Assessment for Gymnocoronis spilanthoides (D. Don ex Hook. & Arn.) DC. (Asteraceae) – Senegal Tea Plant; Assessed Date: 10/12/2016
https://www.aphis.usda.gov/plant_health/plant_pest_info/weeds/downloads/wra/Gymnocoronis_spilanthoides_WRA.pdf

8Global invasive species database; Assessed Date: 10/12/2016
http://www.iucngisd.org/gisd/species.php?sc=863

9Fact sheet of Gymnocoronis spilanthoides – Weed Science Society of America, Assessed Date: 10/12/2016
http://wssa.net/wp-content/uploads/Gymnocoronis-spilanthoides.pdf

10Pest and Damage Report Database; Plant Health and Pest Prevention Services, California Department of Food and Agriculture: Assessed Date: 10/12/2016

Worldwide distribution of Gymnocoronis spilanthoides (G. Fowler, USDA-APHIS-PPQ, Center for Plant Health Science and Technology)

WorldwideDistribution-Gymnocoronis-spilanthhoides

Source: Weed Science Society of America (www.wssa.net)


Responsible Party:

Raj Randhawa, Senior Environmental Scientist; California Department of Food and Agriculture; 1220 N Street, Sacramento, CA 95814; Tel. (916) 654-0317; plant.health[@]cdfa.ca.gov.


Comment Period:  CLOSED

45-day comment period: Nov 2 – Dec 17, 2016


Pest Rating: A |  Proposed Seed Rating: P


Posted by ls 

Parthenium hysterophorus L. | Santa Maria feverfew

2100033-Parthenium-hysterophorusL_CharlesTBryson-USDA-AgResearchService-Bugwood.org
California Pest Rating for
Family: Asteraceae
Parthenium hysterophorus L. – Santa Maria feverfew
Pest Rating: A |  Seed Rating: P

 


PEST RATING PROFILE
Initiating Event:

This plant has been rated as “Q” on the CDFA Plant Pest Rating List after a find in a greenhouse growing in coir from Sri Lanka. There have been two detections of this plant in Orange County in 2016.

Synonym:

Parthenium lobatum Buckley

History & Status:

Santa Maria feverfew is an aggressive, annual, herbaceous weed of highly negative economic importance. This erect, ephemeral herb is known for its vigorous growth and high fecundity, especially in warmer climates. It is native to the southern United States, Mexico, Central and South America; however the native range north of Mexico is not clear. Santa Maria feverfew is a prolific weed belonging to the daisy family (Asteraceae), producing thousands of small flower heads each yielding several single-seeded fruits on reaching maturity. Within the past century it has found its way to Africa, Australia, Asia and many Pacific Islands. It has now become one of the world’s seven most serious weeds in warm climates. It is found on abandoned lands, residential areas, railway tracks, road right-of-ways, drainage and irrigation canals, lawn edges, and other disturbed areas. It has wide adaptability, drought tolerance, high seed production ability and a long-lived soil seed bank. This weed invades established gardens, plantations and vegetable crops. Due to its high fecundity, a single plant can produce 10,000 to 15,000 viable seeds in one year and the fruits can disperse and germinate to cover large areas.

Official Control: Santa Maria feverfew is recognized as invasive weed in certain countries of Asia, Africa and Oceania. In 2014, it was added to the California list of noxious weeds (CCR Section 4500).

Much research has been carried out in South Asia on the control of this plant, including biological control. It has not yet established in California and no work has been done here.

California Distribution: One population was found on the U.C. Campus in Riverside in 1981. This population is evidently gone (Andrew Sanders, pers. comm.). Populations of Santa Maria feverfew have been found growing in two areas of California recently in Orange County (in 2016) and it has not yet naturalized in California.

California Interceptions:  Santa Maria feverfew has not been intercepted at California borders.

United States Distribution: Santa Maria feverfew has a native range in in the subtropical regions of North and South America and has been found in many Eastern states. It is now well established in the Southern United States

International Range: Santa Maria feverfew is native to Mexico, Central and South America. It is distributed in parts of Asia, Africa, North America, the Caribbean, Europe and Oceania.

This risk Santa Maria feverfew would pose to California is evaluated below.

Consequences of Introduction: 

1) Climate/Host Interaction: Santa Maria feverfew is a weed of semi-arid subtropical, tropical and warmer temperate regions. It is often found in riparian zones. It is able to invade natural ecosystems and has the ability to cause habitat changes in native grasslands and open woodlands. The climate in inland regions of California is more continental with some semi-arid areas. The Central Valley has hotter summers with a mediterranean style climate. This weed is likely to establish in small areas of California. Score: 2

Evaluate if the pest would have suitable hosts and climate to establish in California.  Score: 2

Low (1) Not likely to establish in California; or likely to establish in very limited areas.

Medium (2) may be able to establish in a larger but limited part of California.

High (3) likely to establish a widespread distribution in California.

2) Known Pest Host Range: Risk is High (3) as weeds do not require any one host, but grow wherever ecological conditions are favorable. Score: 3

Evaluate the host range of the pest.

Low (1) has a very limited host range.

Medium (2) has a moderate host range.

High (3) has a wide host range.

3) Pest Dispersal Potential: Risk is High (3). The plant produces via numerous seeds that are able to spread rather quickly. Santa Maria feverfew can be dispersed through water, farm machinery, industrial machinery, feral animals, humans, vehicles, stock fodder, and movement of stock, grain and seed (PAG 2000). It can also be spread by wind due to its small and light seed size (Navie et al., 1996; Taye, 2002). Score: 3

Evaluate the natural and artificial dispersal potential of the pest. Score: 3

Low (1) does not have high reproductive or dispersal potential.

Medium (2) has either high reproductive or dispersal potential.

High (3) has both high reproduction and dispersal potential.

4) Economic Impact: Risk is high (3) as the plant can lower range productivity and land value. Santa Maria feverfew has been known to impact pastoral regions and can replace forage plants. This weed is considered to be a cause of allergic respiratory problems, contact dermatitis, and mutagenicity in human and livestock. Crop production is drastically reduced in infested fields owing to its ability to suppress growth of other plants (allelopathy). Santa Maria feverfew can also impact crop production indirectly by serving as an alternate hosts for other plant pests and disease causing organisms. It is estimated that in heavily infested crops, the cultivation costs may be doubled because the prepared ground must be re-worked to eliminate the emergent parthenium weed seedlings (Chippendale and Penetta). Score: 3

Evaluate the likely economic impacts of the pest to California using the criteria below. Score: 3

A. The pest could lower crop yield.

B. The pest could lower crop value (includes increasing crop production costs).

C. The pest could trigger the loss of markets (includes quarantines).

D. The pest could negatively change normal cultural practices.

E. The pest can vector, or is vectored, by another pestiferous organism.

F. The organism is injurious or poisonous to agriculturally important animals.

G. The organism can interfere with the delivery or supply of water for agricultural uses.

Score the pest for Environmental Impact:

Low (1) causes 0 or 1 of these impacts.

Medium (2) causes 2 of these impacts.

High (3) causes 3 or more of these impacts.

5) Environmental Impact: Risk is high (3) as the plant can disrupt natural communities and cultural plants in a landscape. It can cause prolonged toxic effects on the soil environment. The invasive ability and its allelopathy have given Santa Maria feverfew the ability to disrupt ecosystems by replacing dominant flora and suppressing natural vegetation, thereby becoming a threat to biodiversity. Sparse vegetation is seen in infested areas. Santa Maria feverfew has an adverse effect on native plants. It has been reported to cause irreversible habitat change in native Australian grasslands, open woodlands, river banks and flood plains. Santa Maria feverfew rapidly invade new surroundings and often replaces indigenous species. Score: 3

Evaluate the environmental impact of the pest on California using the criteria below:

A. The pest could have a significant environmental impact such as lowering biodiversity, disrupting natural communities, or changing ecosystem processes.

B. The pest could directly affect threatened or endangered species.

C. The pest could impact threatened or endangered species by disrupting critical habitats.

D. The pest could trigger additional official or private treatment programs.

E. The pest significantly impacts cultural practices, home/urban gardening or ornamental plantings.

   Score the pest for Environmental Impact:

Low (1) causes none of the above to occur.

Medium (2) causes one of the above to occur.

High (3) causes two or more of the above to occur.

Consequences of Introduction to California for Santa Maria feverfew:

Add up the total score and include it here. (14)

Low = 5-8 points

Medium = 9-12 points

High = 13-15 points

6) Post Entry Distribution and Survey Information: Only official records identified by a taxonomic expert and supported by voucher specimens deposited in natural history collections should be considered. Pest incursions that have been eradicated, are under eradication, or have been delimited with no further detections should not be included. Score: -1

Not established (0) Pest never detected in California, or known only from incursions.

Low (-1) Pest has a localized distribution in California, or is established in one suitable climate/host area (region).

Medium (-2) Pest is widespread in California but not fully established in the endangered area, or pest established in two contiguous suitable climate/host areas.

High (-3) Pest has fully established in the endangered area, or pest is reported in more than two contiguous or non-contiguous suitable climate/host areas.

Final Score:

The final score is the consequences of introduction score minus the post entry distribution and survey information. Final score: 13

Uncertainty:

The extent of suitable habitat in CA is not clear, but this plant has shown itself to be capable of wide invasion where warmth and some summer water are available.

Conclusion and Rating Justification:

A very bad weed. Despite its limited adaptability to California, it deserves an A rating, as it is so harmful and as it has invaded similar habitats in Australia.

References:

Adkins, S.W. and S.C. Navie. 2006. Parthenium weed: a potential major weed for agro-ecosystems in Pakistan. Pak. J. Weed Sci. Res. 12: 19-36.

Consortium of California Herbaria (ucjeps.berkeley.edu/consortium/).

Flora of North America Editorial Committee, eds.  1993+.  Flora of North America North of Mexico.  16+ vols.  New York and Oxford.

Lakshmi C. & C. R. Srinivas. 2007. Parthenium: A wide angle view. Indian J. Dermatol Venereol Leprol. 73:296–306.

Patel, S. 2011. Harmful and beneficial aspects of Parthenium hysterophorus: an update. 3 Biotech. 1: 1–9.

National Plant Germplasm System: GRIN database: USDA APHIS

https://npgsweb.ars-grin.gov/gringlobal/taxonomydetail.aspx?id

Weeds of the United States and Canada: Southern Weed Science Society (USDA Natural Resource Conservation) http://plants.usda.gov/core/profile?symbol=PAHY

Invasive Species Compendium: Parthenium hysterophorus http://www.cabi.org/isc/datasheet/45573

PAG, 2000. Parthenium weed. Parthenium Action Group Information Document. CSIRO, Australia.

http://www.chris.tag.csiro.au/parthenium/information.html.

Navie SC, McFadyen RE, Panetta FD, Adkins SW, 1996. The biology of Australian weeds. 27. Parthenium hysterophorus L. Plant Protection Quarterly, 11(2):76-88; 4 pp. of ref.

Taye T, 2002. Investigation of pathogens for biological control of parthenium (Parthenium hysterophorus L) in Ethiopia. PhD Thesis. Humboldt University of Berlin, Germany.

Chippendale JF, Panetta FD, 1994. The cost of parthenium weed to the Queensland cattle industry. Plant Protection Quarterly, 9(2):73-76; 14 ref.

Distribution of Santa Maria feverfew in 1994 (Adkins and Navie, 2006)
Distribution of Santa Maria feverfew in 1994 (Adkins and Navie, 2006)

Responsible Party:

Dean G. Kelch, Primary Botanist; California Department of Food and Agriculture; 1220 N Street, Sacramento, CA 95814; Tel. (916) 654-0317; plant.health[@]cdfa.ca.gov.


Comment Period:  CLOSED

45-day comment period: Nov 2 – Dec 17, 2016


Pest Rating: A |  Proposed Seed Rating: P


Posted by ls 

 

Chrysanthemoides monilifera: Bitou bush

California Pest Rating for
Chrysanthemoides monilifera: Bitou bush
Asterales: Asteraceae
Pest Rating: A  |  Proposed Seed Rating: R

 


PEST RATING PROFILE
Initiating Event:

This plant has been recently discovered spreading from a single population in Orange County.

History & Status:

Background:  Bitou bush is a small shrub (to 2 meters) native the Cape Region of South Africa. It is a semi-succulent plant with ascending candelabra-like branches and elliptical leaves without a petiole about 80 mm long. The flowers heads are borne in summer through fall. The ray flowers and disk flowers are bright yellow. Although it most likely arrived in CA as a garden plant, it is no longer available in the trade (except rarely as seed). Its distribution is limited by cold, as it is intolerant of frost.

Official Control: Bitou bush has not been subject to official control.

California Distribution:  Known from 3 historic populations in Orange and San Diego Counties. These most likely are or were persisting from cultivation.

California Interceptions:  None.

United States:  Bitou bush has been reported from California only.

International:  Bitou bush is native to South Africa. It is reported as naturalized and as an environmental weed in Australia and New Zealand where millions of dollars have been spent on control efforts.

This risk Bitou bush would pose to California is evaluated below.

Consequences of Introduction:

1)  Climate/Host Interaction: The plant has had at least 3 introductions in CA. One of these populations is beginning to spread. It is very invasive in eastern Australia in areas with a similar climate to parts of California. Therefore Bitou bush receives a High (3) in this category.

Evaluate if the pest would have suitable hosts and climate to establish in California. Score:

Low (1) Not likely to establish in California; or likely to establish in very limited areas.
Medium (2) may be able to establish in a larger but limited part of California.
High (3) likely to establish a widespread distribution in California.

2)  Host Range:  Risk is High (3) as weeds do not require any one host, but grow wherever ecological conditions are favorable.

Evaluate the host range of the pest. Score:

Low (1) has a very limited host range.
Medium (2) has a moderate host range.
High (3) has a wide host range.

3)  Pest Dispersal Potential:  Bitou bush produces via numerous achenes (“seeds”) that are enclosed in a fleshy fruit dispersed by birds. Bird dispersal is an efficient means of plants establishing new populations. The seed bank is moderately persistent. Known populations have not spread until recently. Bitou bush receives a Medium (2) in this category.

Evaluate the natural and artificial dispersal potential of the pest. Score:

Low (1) does not have high reproductive or dispersal potential.
Medium (2) has either high reproductive or dispersal potential.
High (3) has both high reproduction and dispersal potential.

4)  Economic Impact:  Bitou bush does not persist well in grazed areas due to browsing and trampling. Bitou bush receives a Low (1) in this category.

Evaluate the economic impact of the pest to California using the criteria below. Score:

A.   The pest could lower crop yield.
B.   The pest could lower crop value (includes increasing crop production costs).
C.   The pest could trigger the loss of markets (includes quarantines).
D.   The pest could negatively change normal cultural practices.
E.   The pest can vector, or is vectored, by another pestiferous organism.
F.   The organism is injurious or poisonous to agriculturally important animals.
G.   The organism can interfere with the delivery or supply of water for agricultural uses.

Low (1) causes 0 or 1 of these impacts.
Medium (2) causes 2 of these impacts.
High (3) causes 3 or more of these impacts.

5)  Environmental Impact:  Chrysanthemoides monilifera out competes native vegetation in coastal environments in Australia and New Zealand, and invasion can lead to a decline in both floral and faunal diversity, changing ecosystem composition. It changes ecosystem processes by altering nutrient cycling, particularly nitrogen cycling, at the expense of native species and creating heavy shade in normally high light areas. It is considered a “weed of national significance” in Australia and has replaced entire stands of native species. This species is tolerant of saline conditions near coastal areas. In addition, it can create a favorable environment for other invasive weeds. Rare taxa that might be affected include strand species such as Laguna Beach dudleya (Dudleya stolonifera) and sagebrush scrub species such as California gnatcatcher (Polioptila californica). Because it forms dense patches, it could interfere with recreation along the coast and invade expensive coastal properties requiring control. Bitou bush receives a High (3) in this category.

Evaluate the environmental impact of the pest on California using the criteria below.

A.   The pest could have a significant environmental impact such as lowering biodiversity, disrupting natural communities, or changing ecosystem processes.
B.   The pest could directly affect threatened or endangered species.
C.   The pest could impact threatened or endangered species by disrupting critical habitats.
D.   The pest could trigger additional official or private treatment programs.
E.   The pest significantly impacts cultural practices, home/urban gardening or ornamental plantings.

Score the pest for Environmental Impact. Score:

Low (1) causes none of the above to occur.
Medium (2) causes one of the above to occur.
High (3) causes two or more of the above to occur.

Consequences of Introduction to California for Bitou bush: Medium (12)

Add up the total score and include it here.

–  Low = 5-8 points
–  Medium = 9-12 points
–  High = 13-15 points

6)  Post Entry Distribution and Survey Information:  Bitou bush is very local in CA. It receives a Low (-1) in this category.

Evaluate the known distribution in California. Only official records identified by a taxonomic expert and supported by voucher specimens deposited in natural history collections should be considered. Pest incursions that have been eradicated, are under eradication, or have been delimited with no further detections should not be included.

–  Not established (0) Pest never detected in California, or known only from incursions.
–  Low (-1) Pest has a localized distribution in California, or is established in one suitable climate/host area (region).
–  Medium (-2) Pest is widespread in California but not fully established in the endangered area, or pest established in two contiguous suitable climate/host areas.
–  High (-3) Pest has fully established in the endangered area, or pest is reported in more than two contiguous or non-contiguous suitable climate/host areas.

Final Score:

The final score is the consequences of introduction score minus the post entry distribution and survey information score: Medium (11)

Uncertainty:

As Bitou bush has invaded Australia and is beginning to spread in CA, uncertainty is low.

Conclusion and Rating Justification:

A potentially bad weed in CA.  Bitou bush merits an “A” rating to prevent its further spread in California. It has a low risk as a potential seed contaminant, so it should be restricted in seed for planting.

References:

Adamson, R. S. & T. M. Salter 1950. Flora of the Cape Peninsula. Juta & Co. Cape Town.

Baldwin, B. G., D. H. Goldman, D. J. Keil, R. Patterson, T. J. Rosatti, & D. H. Wilken, editors. 2012. The Jepson manual: vascular plants of California, second edition. University of California Press, Berkeley.

Bond, P. & P. Goldblatt 1984. Plants of the Cape Flora: A descriptive catalogue. National Botanic Gardens of South Africa, Kirstenbosch.

Consortium of California Herbaria accessed 1/21/2015: ucjeps.berkeley.edu/consortium/

Coutts-Smith, A. J., & P. O. Downey. 2006. Impact of weeds on threatened biodiversity in NSW. CRC for Australian Weed Management, Adelaide, Australia.

Flora of North America Editorial Committee, eds. 1993+. Flora of North America North of Mexico. 16+ vols. New York and Oxford.

Grice, A. C., S. Campbell, R. Breaden, F. Bebawi, & W. Vogler. 2008. Habitat management guide-Rangelands: Ecological principles for the strategic management of weeds in rangeland habitats. CRC for Australian Weed Management, Adelaide, Australia.

Lindsay, E. A., & K. French. 2005. Litterfall and nitrogen cycling following invasion by Chrysanthemoides monilifera ssp. rotundata in coastal Australia. Journal of Applied Ecology 42: 556-566.

USDA Weed Risk Assessment of Chrysanthmoides monilifera accessed 1/21/2015: http://www.aphis.usda.gov/plant_health/plant_pest_info/weeds/downloads/wra/Chrysanthemoides_monilifera_WRA.pdf

Responsible Party:

Dean G. Kelch, Primary Botanist; California Department of Food and Agriculture; 1220 N Street, Sacramento, CA 95814; Tel. (916) 654-0312; plant.health[@]cdfa.ca.gov.


Comment Period: CLOSED

The 45-day comment period opened on Monday, March 16, 2015 and closed on Thursday, April 30, 2015.


Pest Rating: A  |  Proposed Seed Rating: R


Posted by ls