Tag Archives: weeds

Slender Russian Thistle | Salsola collina

California Pest Rating for
Click on image for photo citation.
Slender Russian Thistle  |  Salsola collina Pallas
Caryophyllales: Chenopodiaceae
Pest Rating: A  |  Proposed Seed Rating: P

 


PEST RATING PROFILE

Initiating Event:

Salsola collina Pallas is a listed as a noxious weed in California . It is regarded as an invasive weed in Colorado. It has widespread distribution in many U.S. states and Canada. This plant has been introduced in lower 48 states and is considered a major noxious weed in North America. It has not been reported growing in natural environment of California. Currently, it has been rated as “A”. A pest risk proposal is required to evaluate this rating.

History & Status:

BackgroundSalsola collina is an erect annual forb in the goosefoot family. It is a round, bushy, much branched plant growing 1-3.5 feet high. The branches are slender and soft when young and woody when mature. The leaves are alternate. Flowers are small, green white or pink in color. It produces about 30 seeds per seed head (Swearingen & Bargeron, 2016).

Salsola collina was reported for the first time in North America from Minnesota by J.W. Moore in 1938. Later it was discovered in Colorado, Iowa and Missouri. Reports of S. collina for Arizona and New York are based on specimen cited by S. Rilke in 1999. Its actual distribution seems to be underestimated because of its confusion with deviant forms of S. tragus. (Flora of North America).

Slender Russian thistle typically grows in sandy soils on dry plains, in cultivated fields, roadsides, waste places, grain growing areas and disturbed plant communities. It prefers light to medium soils but can also grow in vary alkaline and saline soils. The only limitation is that it cannot grow in shade (USDA Forest Services, 2006).

Worldwide DistributionSalsola collina is native to eastern Europe and Asia. It is considered as a Eurasian import and has become a dominant tumble weed in North America. This species is reported to be widespread in Midwestern states of United States and Canada. It is currently present in Colorado, Iowa, Illinoise, Kansas, Kentucky, Massachusetts, Minnesota, Missouri, Montana, North Dakota, Nebraska, Oklahoma, South Dakota, Utah, West Virginia and Wyoming. In Canada, it is distributed in the province of Alberta, Manitoba, Ontario and Saskatchewan (Kartesz, 1994). This species is considered invasive in Colorado and a quarantine weed in California.It has been introduced in China, Australia (in Northern Territory and Queensland where it is considered to be a pest plant of national importance), the Caribbean, Indian Ocean islands, Mauritius, the United States, Central America, South America and the Galápagos Islands. It has naturalized in several countries where it has been introduced as a medicinal, forage and fuelwood plant. It has been introduced in China, Australia (in Northern Territory and Queensland where it is considered to be a pest plant of national importance), the Caribbean, Indian Ocean islands, Mauritius, the United States, Central America, South America and the Galápagos Islands. It has naturalized in several countries where it has been introduced as a medicinal, forage and fuelwood plant.

Official ControlSalsola collina is not listed as a harmful organism in any other country. However, other Salsola species like S. tragus have been reported as harmful organism in Brazil (PCIT-PExD).

California Distribution: Salsola Collina has not been found growing in the natural environment in California

California InterceptionsSalsola collina has been intercepted 83 times from January 1990 through October 2017 by CDFA. These interceptions were mostly through various border stations inspections of vehicles entering the state (PHPPS- PDR Database)

The risk Salsola Collina (Slender Russian thistle) would pose to California is evaluated below.

Consequences of Introduction:

1) Climate/Host Interaction: Salsola collina has the ability to grow in dry plains areas of California’s central valley extending from Shasta County in north to Imperial County in the south. (CA Plains Database, 2017).The ability of this plant to grow on roadsides, grain growing areas and naturally disturbed areas make it vulnerable to grow in these areas in California. It 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) Known Pest Host Range: Salsola collina does not need one particular host but grow wherever ecological conditions are favorable. This species can grow on plains, semi natural and naturally disturbed areas, abandoned and cultivated fields and waste places in California. It cannot grow in shade and in areas with heavy soil types. It receives a High (3) in this category

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: Salsola collina reproduces by seeds. It produces 30 seeds per seed head. This plant flowers from July to September and the seeds ripen from September to October. Seeds remain viable for less than a year. Seeds dispersal can happen when plants are mowed after seeds set occurs. Tillage can favor germination of seeds. Roads and highway may allow windblown plants to disperse to long distance, spreading seeds to a wider area. It 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: Salsola collina can reduce yield and quality of various agricultural crops. It can depletes soil moisture, interfere with tillage operations. Large windblown plants can reduce highway safety by obstructing views along right of ways. (USDA- Forest Services, 2006). It receives a Medium (2) in this category

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

Economic Impact: A, D

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.

Economic Impact Score: 2

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:  Salsola Collina is likely to threaten native plant ecosystems. It has the ability to deplete soil moisture. Windblown plants can accumulate along trees and fence lines and can possibly cause serious fire hazards in dry plains of California.  Salsola collina is not likely to impact threatened and endangered species, however it can impact the quality of cultivated plants and is a roadside nuisance. It receives a High (3) in this category

Environmental Impact: A, C

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: 3

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 Salsola collina (slender russian thistle) High (13)

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:  Salsola Collina has not been found occurring in natural environment of California and receives a Not established (0) 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: High (13)

Uncertainty:

Salsola Collina is a noxious and quarentine weed in California and CDFA has been successfully intercepting this species at the state borders. Another similar species, Salsola tragus is a common species in California. Because S. collina resembles S. tragus, there may be a possibility that this species is present in southern California where large infestations of S. tragus occur (Cal –IPC, 2017)

Conclusion and Rating Justification:

Salsola Collina  has not been found in the natural environment of California. If this species were to introduce accidently, it can cause significance economic and environmental impacts to agricultural and natural resources of California. Therefore, an “A” rating is justified.

References:

California Invasive Species Council, 2017. Plant assessment form. Salsola tragushttp://www.cal-ipc.org/plants/paf/salsola-tragus-plant-assessment-form/

California Plains Database, 2017. CA home town locator. Local information, resources and data  https://california.hometownlocator.com/features/physical,class,plain.cfm

Flora of North America. Volume 4, page 399,400,402  http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=200006908

Kartesz, J.T. 1994. A synonymized checklist of the vascular flora of the United States, Canada, and Greenland. 2nd edition. 2 vols. Timber Press, Portland, OR.  http://explorer.natureserve.org/servlet/NatureServe?searchName=Salsola%20collina

Pest and Damage Record Database, Plant Health and Pest Prevention Services, California Department of Food and Agriculture. Accessed 11/17/2017  http://phpps.cdfa.ca.gov/user/frmLogon2.asp

Swearingen, J., C. Bargeron. 2016. Invasive Plant Atlas of the United States. University of Georgia Center for Invasive Species and Ecosystem Health https://www.invasiveplantatlas.org/subject.html?sub=6354

Phytosanitary Certificate Issuance & Tracking System (PCIT), Phytosanitary Export Database (PExD), USDA, APHIS. Accessed 11/17/2017 https://pcit.aphis.usda.gov/PExD/faces/ReportFormat.jsp


Author:

Raj Randhawa, 1220 ‘N’ Street, Room 221, Sacramento CA 95814, (916)403-6617, raj.randhawa@cdfa.ca.gov

Responsible Party:

Dean G. Kelch, Primary Botanist; California Department of Food and Agriculture; 1220 N Street, Sacramento, CA 95814; Tel. (916) 403-6650;  plant.health[@]cdfa.ca.gov.


Comment Period: * CLOSED

2/20/2018 – 4/6/2018


*NOTE:

You must be registered and logged in to post a comment.  If you have registered and have not received the registration confirmation, please contact us at plant.health[@]cdfa.ca.gov.


Comment Format:

♦  Comments should refer to the appropriate California Pest Rating Proposal Form subsection(s) being commented on, as shown below.

Example Comment:
Consequences of Introduction:  1. Climate/Host Interaction: [Your comment that relates to “Climate/Host Interaction” here.]

♦  Posted comments will not be able to be viewed immediately.

♦  Comments may not be posted if they:

Contain inappropriate language which is not germane to the pest rating proposal;

Contains defamatory, false, inaccurate, abusive, obscene, pornographic, sexually oriented, threatening, racially offensive, discriminatory or illegal material;

Violates agency regulations prohibiting sexual harassment or other forms of discrimination;

Violates agency regulations prohibiting workplace violence, including threats.

♦  Comments may be edited prior to posting to ensure they are entirely germane.

♦  Posted comments shall be those which have been approved in content and posted to the website to be viewed, not just submitted.


Pest Rating: A  |  Proposed Seed Rating: P

 


Posted by ls

Mexican Pokeweed | Phytolacca heterotepala

California Pest Rating for
Photo by: Robert Sikora
Mexican pokeweed | Phytolacca heterotepala H. Walter
Caryophyllales: Phytolaccaceae
Pest Rating: A  |  Proposed Seed Rating: R

 


PEST RATING PROFILE

Initiating Event:

Phytolacca heterotepala has been present as a weed in the San Francisco Bay Area since the 1950s. It was recently found for the first time growing in a pasture in San Luis Obispo County (PDR 400P06359971, 400P06359972; Cal Flora 2018) and confirmed as a new county record. Phytolacca heterotepala is currently Q-rated. A permanent pest rating proposal is required to support an official pest rating.

History and Status:

Background: Phytolacca heterotepala was first documented from California in 1915 from a nursery in San Francisco [A. Eastwood s.n. CAS] (Howell 1960). Naturalized populations were documented starting in 1955 for San Francisco County [L. Jones s.n., CAS-BOT-BC434466], in 1959 for Santa Barbara County [E. Blakley 2942, CAS-BOT-BC434440], in 1960 for Santa Clara County [J. H. Thomas 8763 1960, DS577499], in 1974 for Marin County [P. Ellman s.n., CAS652035], and in 2003 for Alameda County [S. Pugh s.n., JEPS103234] (Howell 1960, Munz and Keck 1968, CAS Botany Collection Database 2018, CCH 2018). Except for some San Francisco collections, most of these comprise waits in disturbed areas or gardens.The populations from Santa Clara and Santa Barbara counties are presumed extirpated.

Plants can reach 2.5 m (Jepson eFlora 2018, Nienaber and Thieret 2004). Sepals are greenish, oblong and unequal; the largest sepal is twice as wide as the smallest. The stamens are in two whorls. It has been documented in California establishing from cultivation and in disturbed areas at an elevation up to 100 meters. Flowering starts in summer and continues into the winter months (Jepson Flora).

Phytolacca heterotepala may be mistaken for the more common and widespread Phytolacca americana L, which is introduced in California and native to the eastern United States. Phytolacca heterotepala is similar morphologically to and sometimes treated as a synonym of Phytolacca icosandra L. (red inkplant, tropical pokeweed), which is native to Arizona, Mexico, and northern South America and introduced in California (San Diego County) (CCH 2018, Davis 1985, Rzedowski and Calderón de Rzedowski 2000, Steinmann 1997, Xu et al. 2017). We follow treatments of the genus for California (Howell 1960, Jepson eFlora 2018), North America (Nienaber and Thieret 2004), and phylogenetically (Ali et al. 2015).

Synonyms: Not known.

Worldwide Distribution: Phytolacca heterotepala is native to Mexico and northern South America. In addition to its introduction and establishment in California, this taxon is documented as a newly established (Ortiz 1987) and invasive species in two areas of Portugal (Domingues de Almeida and Freitas 2006, Invasive plants in Portugal, 2016).

Official Control: Phytolacca heterotepala has not been reported as a harmful plant in other states and nations (USDA APHIS PCIT).

California Distribution: Phytolacca heterotepala has been present as a weed in the San Francisco Bay Area since the 1950s, and recently has been found in San Luis Obispo County (Jepson eFlora 2018, CalFlora 2018).

California Interceptions: Phytolacca heterotepala has been intercepted twice by CDFA in 2017 through general surveys in San Luis Obispo County (PDR 400P06359971, 400P06359972; CalFlora po67404).

The risk Phytolacca heterotepala (Mexican pokeweed) would pose to California is evaluated below.

Consequences of Introduction:

1) Climate/Host Interaction: Phytolacca heterotepala has the ability to grow in disturbed areas of California and persist from cultivation. Since its presence has been observed in north coast and central coast areas, it may be able to spread to south coast areas of California. It is unknown if it may spread to inland areas of the state It receives a Low (1) 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) Known Pest Host Range: Phytolacca heterotepala does not need one particular host but grow wherever ecological conditions are favorable. It receives a High (3) in this category

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: Phytolacca produces multiseeded fleshy berries that are eaten and dispersed by birds. It can reproduce vegetatively from root sprouts. It has not spread widely despite being present in CA for more than 100 years.. It 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: All parts of Phytolacca spp. (pokeweed, pokesalad) are potentially toxic to mammals (Roberge et al. 1986, FDA Poisonous Plant Database 2008. If this species spreads in California, hand pulling and foliar applications could increase production costs. Manual removal is not recommended without appropriate personal protection, and once established, eradication can be difficult. Although PAPs provide plant defence and resistance to infection by viruses and some fungus, Phytolacca is a host of pokeweed crinkle virus (, that can infect sugar beets, chard, spinach, and cucumber (Lackey 1965). However, it currently, has only been detected in urban waste areas. It has not spread to agricultural areas despite its long presence along the central coast of CA. It receives a Medium (2) in this category

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

Economic Impact: E, F

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.

Economic Impact Score: 2

-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: Pokeweed crinkle virus can infect native California species (e.g., Adenostoma, Eriogonum), and may affect rare and endangered taxa (Lackey 1965). Phytolacca heterotepala occurs in disturbed areasand may outcompete other weeds.. It receives a Medium (2) in this category.

Environmental Impact: A

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: 2

-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 Phytolacca heterotepala (Mexican pokeweed): Medium (10)

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: Phytolacca heterotepala is naturalized in the San Francisco Bay Area (Alameda, Marin, San Francisco counties) and recently documented in San Luis Obispo County. Two historic naturalized populations (Santa Clara and Santa Barbara counties) are presumed extirpated. 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 (9)

Uncertainty:

Phytolacca heterotepala has been present as a weed in the San Francisco Bay Area since the 1950s. The recent interceptions in San Luis Obispo County indicate that it may be spreading. No recent surveys have been performed for this taxon in California, so it may be possible that Phytolacca heterotepala occurs elsewhere in the state. Lacking studies, there is uncertainty regarding impacts to California’s agricultural and natural resources.

If plants suspected to be Phytolacca heterotepala are found in your area, please submit samples to the nearest Agricultural Commissioner office or to Botany California Department of Food and Agriculture, Plant Pest Diagnostic Center t Botany Lab for determination and vouchering as specimens in the plant herbarium.

Conclusion and Rating Justification:

Although Phytolacca heterotepala has been present as a weed in the San Francisco Bay Area since at least 1950s, it has recently spread to San Luis Obispo County. There is potential to spread into additional, suitable habitats but these areas are disturbed and weedy in nature. Therefore, an “A” rating is justified.

References:

Ali, M. A., J. Lee, S.-Y. Kim, S.-H. Park, and F. M. Al-Hemaid. 2015. Molecular phylogenetic analyses of internal transcribed spacer (ITS) sequences of nuclear ribosomal DNA indicate monophyly of the genus Phytolacca L. (Phytolaccaceae). Bangladesh Journal of Plant Taxonomy 22(1):1-8.

The Calflora Database [A Non-Profit Organization]. 2018. Calflora: Information on California plants for education, research and conservation, with data contributed by public and private institutions and individuals, including the Consortium of California Herbaria [web application] Accessed January 24,  2018.  http://www.calflora.org/cgi-bin/noccdetail.cgi?seq_num=po67404

California Academy of Sciences [CAS]. 2010–2018. Institute for Biodiversity Science and Sustainability, Department of Botany, California Academy of Sciences [CAS]. CAS Botany Collection Database. Accessed January 24, 2018.  http://researcharchive.calacademy.org/research/botany/coll_db/index.asp

Consortium of California Herbaria [CCH]. 2018. Data provided by the participants of the Consortium of California Herbaria [CCH]. Regents of the University of California 2018. Accessed January 24, 2018. http://ucjeps.berkeley.edu/consortium/

Davis, J. I. 1985. Introgression in Central American Phytolacca (Phytolaccaceae). American Journal of Botany 72(12):1944-1953.

Domingues de Almeida, J. D., and H. Freitas. 2006. Exotic naturalized flora of continental Portugal-A reassessment. Botanica complutensis 30:117-130.

FDA Poisonous Plant Database. 2008 (data updated May 2008). Accessed January 24, 2018 https://www.accessdata.fda.gov/scripts/Plantox/

Howell, J. T. 1960. A Mexican pokeberry in San Francisco, California. Leafl. W. Bot. 9: 81–83.

iNaturalist. 2018. Accessed January 24, 2018.  http://www.inaturalist.org

Invasive plants in Portugal, 2016. Phytolacca Americana- Factsheet  http://invasoras.pt/en/gallery/phytolacca-americana-en/

Irvin, J. D., and F. M. Uckun. 1992. Pokeweed antiviral protein: ribosome inactivation and therapeutic applications. Pharmacology & therapeutics 55(3):279-302.

Jepson eFlora. Accessed January 24, 2018  http://ucjeps.berkeley.edu/eflora/eflora_display.php?tid=38167

Lackey, C. F. 1965. Pokeweed crinkle leaf, caused by a virus transmitted by dodder from desert shrubs in Southern California. Plant Disease Reporter 49(12):1002-1005.

Munz, P. A., and D. D. Keck. 1968. A California flora and supplement. University of California Press, Berkeley, CA.

Nienaber, M.A., and J. Thieret. 2004. Phytolaccaceae. Pp. ##–## in Flora North America Editorial Committee (eds.) Flora of North America North of Mexico, Vol. 4: Magnoliophyta: Caryophyllidae, Part 1. Oxford University Press, New York, NY. Accessed January 24, 2018. http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=242415004

Ortiz, S. 1987. Phytolacca heterotepala H. Walter en Portugal. Anales del Jardín Botánico de Madrid 44(2):555.

Phytosanitary Certificate Issuance & Tracking System (PCIT), Phytosanitary Export Database (PExD), USDA, APHIS. Accessed January 23, 2018.  https://pcit.aphis.usda.gov/PExD/faces/PExDReport.jsp

Roberge, R., E. Brader, M. L. Martin, D. Jehle, T. Evans, F. Harchelroad, G. Magreni, G. Gesualdi, C. Belardi, and M. Sayre. 1986. The root of evil—pokeweed intoxication. Annals of emergency medicine 15(4):470-473.

Rzedowski, J., and G. Calderón de Rzedowski. 2000. Notas sobre el género Phytolacca (Phytolaccaceae) en México. Acta Botanica Mexicana 53:49-66.

Steinmann, V. W. 1997. Phytolacca icosandra L.(Phytolaccaceae): new to the continental United States. Madroño 44(1):108-109.

Xu, S. Z., Z. Y. Li, and X. H. Jin. 2017. DNA barcoding of invasive plants in China: A resource for identifying invasive plants. Molecular Ecology Resources doi.org/10.1111/1755-0998.12715.


Author:

Raj Randhawa, 1220 ‘N’ Street, Room 221, Sacramento CA 95814, (916)403-6617, raj.randhawa@cdfa.ca.gov

Responsible Party:

Dean G. Kelch, Primary Botanist; California Department of Food and Agriculture; 1220 N Street, Sacramento, CA 95814; Tel. (916) 403-6650;  plant.health[@]cdfa.ca.gov.


Comment Period: * CLOSED

2/20/2018 – 4/6/2018


*NOTE:

You must be registered and logged in to post a comment.  If you have registered and have not received the registration confirmation, please contact us at plant.health[@]cdfa.ca.gov.


Comment Format:

♦  Comments should refer to the appropriate California Pest Rating Proposal Form subsection(s) being commented on, as shown below.

Example Comment:
Consequences of Introduction:  1. Climate/Host Interaction: [Your comment that relates to “Climate/Host Interaction” here.]

♦  Posted comments will not be able to be viewed immediately.

♦  Comments may not be posted if they:

Contain inappropriate language which is not germane to the pest rating proposal;

Contains defamatory, false, inaccurate, abusive, obscene, pornographic, sexually oriented, threatening, racially offensive, discriminatory or illegal material;

Violates agency regulations prohibiting sexual harassment or other forms of discrimination;

Violates agency regulations prohibiting workplace violence, including threats.

♦  Comments may be edited prior to posting to ensure they are entirely germane.

♦  Posted comments shall be those which have been approved in content and posted to the website to be viewed, not just submitted.


Pest Rating: A  |  Proposed Seed Rating: R

 


Posted by ls

Tree of Heaven | Ailanthus altissima (Miller)

California Pest Rating for
Tree of Heaven  |  Ailanthus altissima (Miller)
Family: Simaroubaceae
Pest Rating: C | Proposed Seed Rating: R

 


PEST RATING PROFILE

Initiating Event:

This plant has been included on the CDFA noxious weed list.

History & Status:

Background: Tree of heaven is a (mostly) dioecious, medium-sized tree that grows to approximately 30 meters high.  The long (>50 cm), pinnately compound leaves contain 13-25 lanceolate leaflets measuring 8-13 centimeters each.  Fruits are produced in large clusters and are winged, facilitating dispersal via wind.  The tree can root sprout vigorously, especially when damaged, forming thickets of 100s of stems covering over 0.4 hectares. Tree of heaven was planted extensively in the early days of California and many of these plants have persisted as clonal clumps or thickets.

Worldwide Distribution: Tree of heaven is native to China and has been introduced to many temperate localities throughout the world, including the United States.

Official Control: This tree is listed as a noxious weed by at least five states (California, Connecticut, Massachusetts, New Hampshire, Oregon, and Vermont).

California Distribution: Tree of heaven is widespread in California; it has been reported in 39 counties (Alameda, Amador, Butte, Calaveras, Contra Costa, El Dorado, Fresno, Humboldt, Inyo, Los Angeles, Kern, Marin, Mariposa, Mendocino, Monterey, Napa, Nevada, Orange, Placer, Riverside, Sacramento, San Bernardino, San Diego, San Francisco, San Joaquin, San Luis Obispo, San Mateo, Santa Clara, Santa Cruz, Siskiyou, Solano, Sonoma, Stanislaus, Sutter, Trinity, Tuolomne, Tulare, Ventura, and Yolo).

California Interceptions: Tree of heaven is submitted to the CDFA Botany Lab about once a year for identification.

The risk tree of heaven would pose to California is evaluated below.

Consequences of Introduction:

1) Climate/Host Interaction: It is apparent that tree of heaven can tolerate the conditions found throughout much of the state of California, because it is already present over much of the state. Therefore, it receives a High (3) in this category.

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: Tree of heaven does not require any one host, but grows wherever ecological conditions are favorable. It receives a High (3) in this category.

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: Tree of heaven can reproduce via seed as well as clonally. Seeds are produced in great number (up to one million seeds/tree/year) and can be dispersed via wind.  However, it only rarely reproduces by seed in California and then only along riparian corridors. Most populations or clusters of trees are persisting from horticulture. Due to its ability to root sprout, tree of heaven can be very long-lived and hard to eradicate. Therefore, it receives a Medium (2) in this category.

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: Tree of heaven can cause damage to structures, etc. in urban areas. The leaves are apparently somewhat irritating to skin.  However, there does not appear to be any data quantifying economic damage resulting from this species.  Therefore, it receives a Low (1) in this category.

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.

Economic Impact Score: 1

-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: Although it is often associated with disturbed or urban areas, tree of heaven appears to be able to compete successfully with native plants. Disturbed and riparian habitats appear to be especially threatened.  Impacts in California are unknown, but this tree is common in riparian areas and may be displacing native plants.   Characteristics of tree of heaven that could allow it to displace native flora include clonal reproduction and allelopathic chemicals found in its tissues, which have been shown to inhibit germination and growth of other plants.  Tree of heaven is considered an invasive wildland pest plant by the California Invasive Plant Council.   Therefore, it receives a High (3) in this category.

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

Environmental Impact: A, C

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: 3

-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 tree of heaven: Medium (12).

Low = 5-8 points

Medium = 9-12 points

High = 13-15 points

6) Post Entry Distribution and Survey Information: Tree of heaven is already present over much of California. Therefore, it receives a High (-3) 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 (9)

Uncertainty:

Although tree of heaven has been present in the United States for a long time, it appears to still be spreading in the western part of the country, including California.  The full impact of this species, especially in riparian areas, may be yet to be seen. However, unlike in eastern North America, there is little indication that tree of heaven commonly established via seed in California.

Conclusion and Rating Justification:

Tree of heaven may be a serious threat where it has been planted in the past, especially in riparian areas.  However, it is already widely distributed across the state.  A “C” rating is justified.


References:

Calflora http://www.calflora.org

California Invasive Plant Council. http://cal-ipc.org

Consortium of California Herbaria. http://ucjeps.berkeley.edu/consortium

Encyclaweedia. https://www.cdfa.ca.gov

Jepson eFlora. http://ucjeps.berkeley.edu/eflora

Kowarik, I. and I. Säumel.  2007.  Biological flora of Central Europe: Ailanthus altissima (Mill.) Swingle.  Perspectives in Plant Ecology.  8: 207-237.

Lawrence, J.G.  1991.  The ecological impact of allelopathy in Ailanthus altissima (Simaroubaceae).  American Journal of Botany.  78(7): 948-958.

Oregon Department of Agriculture, Noxious Weed Control Program http://www.oregon.gov/oda/shared/Documents/Publications/Weeds/TreeOfHeavenProfile.pdf

United States Department of Agriculture, Plants database. https://plants.usda.gov

United States Forest Service, Fire Effects Information System. https://www.feis-crs.org/feis/


Author:

Kyle Beucke, 1220 N Street, Room 221, Sacramento, CA, 95814, 916-403-6741, plant.health[@]cdfa.ca.gov

Responsible Party:

Dean G. Kelch, Primary Botanist; California Department of Food and Agriculture; 1220 N Street, Sacramento, CA 95814; Tel. (916) 403-6650;  plant.health[@]cdfa.ca.gov.


Comment Period:* CLOSED

1/17/2018 – 3/3/2018


*NOTE:

You must be registered and logged in to post a comment.  If you have registered and have not received the registration confirmation, please contact us at plant.health[@]cdfa.ca.gov.


Comment Format:

♦  Comments should refer to the appropriate California Pest Rating Proposal Form subsection(s) being commented on, as shown below.

Example Comment:
Consequences of Introduction:  1. Climate/Host Interaction: [Your comment that relates to “Climate/Host Interaction” here.]

♦  Posted comments will not be able to be viewed immediately.

♦  Comments may not be posted if they:

Contain inappropriate language which is not germane to the pest rating proposal;

Contains defamatory, false, inaccurate, abusive, obscene, pornographic, sexually oriented, threatening, racially offensive, discriminatory or illegal material;

Violates agency regulations prohibiting sexual harassment or other forms of discrimination;

Violates agency regulations prohibiting workplace violence, including threats.

♦  Comments may be edited prior to posting to ensure they are entirely germane.

♦  Posted comments shall be those which have been approved in content and posted to the website to be viewed, not just submitted.


Pest Rating: C | Proposed Seed Rating: R


Posted by ls

Giant Ragweed | Ambrosia trifida L.

California Pest Rating for
Giant Ragweed | Ambrosia trifida L.
Family: Asteraceae
Pest Rating: B

 


PEST RATING PROFILE

Initiating Event:

This plant has been included on the CDFA noxious weed list.

History & Status:

Background: Giant ragweed is a large (to 2 meters tall), annual herb.  The stems have black, longitudinal lines and are covered with hairs.  Leaves are palmately 3- to 5-lobed and are sparsely covered with tiny, stiff hairs.  Fruits (“burrs”) are 6-12 mm long and are tapered and blunt on one end and widened with 5-8 teeth on the other end.   Giant ragweed grows best in disturbed areas with moist, fertile soil, and it is an important weed.  Ragweed pollen is a major cause of allergies, and the pollen of this species is a known allergen.

Worldwide Distribution: Native to eastern North America.  Giant ragweed has been introduced to, and is now established in western North America and much of Asia and Europe.

Official Control: Giant ragweed is listed as a noxious weed in at least three states (California, Delaware, and Illinois).

California Distribution: Giant ragweed has been reported in 10 California counties (Contra Costa, Glenn, Orange, Los Angeles, Madera, Monterey, San Diego, San Joaquin, San Luis Obispo, and Siskiyou).  Most of these records are from residential gardens.  According to one source, it is not naturalized in California, but occurs as a waif and/or garden escape.

California Interceptions: Recent collections from 2011 through 2014 originated from gardens or as seed contaminants intercepted at the CA border.  It is commonly intercepted in feed seed shipments entering the state.

The risk giant ragweed would pose to California is evaluated below.

Consequences of Introduction:

1) Climate/Host Interaction: Giant ragweed thrives in temperate climates, and it is already present in ten counties in California. Therefore, it receives a High (3) in this category.

-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: Giant ragweed does not require any one host, but grows wherever ecological conditions are favorable. It receives a High (3) in this category.

-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: Most seeds of giant ragweed fall near the parent plant and they are apparently not eaten in large number by wildlife. However the seeds float and are apparently able to be transported readily via water.  Therefore, it receives a Medium (2) in this category.

-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: Giant ragweed is an important weed in crop systems, especially corn and soybean. Infestations could lead to a loss of markets.  Giant ragweed has already developed resistance to herbicides, so it could increase production costs.   Therefore, it receives a High (3) in this category.

Economic Impact: A, B, C

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.

Economic impact Score: 3

-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: Giant ragweed is able to out-compete other plants in open areas, including crop systems as well as grasslands. It has been scored as a plant with a high risk of invasiveness by the California Invasive Plant Council.  Giant ragweed is often controlled with herbicides, and it has developed resistance to certain pesticides.  It could trigger new treatment programs.  Therefore, it receives a High (3) in this category.

Environmental Impact: A, D

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.

Environmental Impact Score: High (3)

-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 giant ragweed: High (14)

-Low = 5-8 points

-Medium = 9-12 points

-High = 13-15 points

6) Post Entry Distribution and Survey Information: Giant ragweed has been reported in ten California counties, but it seems likely that its distribution within the state could expand further. Therefore, it receives a Medium (-2) in this category.

-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 (12).

Uncertainty:

As stated before, giant ragweed has been present in California for at least 80 years.  Many of the available records are from residential gardens.  It has not, so far, been shown to be a serious problem either agriculturally or environmentally in this state; nevertheless, there is a chance that if it made its way to a new, favorable locality in the state it could behave differently.

Conclusion and Rating Justification:

Based on the potential economic and environmental impact of this weed, and the fact that it is commonly found on feed mill seed entering the state (and is likely to have further opportunities for establishment without regulation), a “B” rating is justified.


References:

Bassett, I.J. and C.W. Crompton.  1982.  The biology of Canadian weeds. 55. Ambrosia trifida L.  Canadian Journal of Plant Science.  62: 1003-1010.

Bullock, J.M., Chapman, D., Schafer, S., Roy, D., Girardello, M., Haynes, T., Beal, S., Wheeler, B., Dickie, I., Phang, Z., Tinch, R., Čivić, K., Delbaere, B., Jones-Walters, L., Hilbert, A., Schrauwen, A., Prank, M., Sofiev, M., Niemelä, S., Räisänen, P., Lees, B., Skinner, M., Finch, S., and C. Brough.  2010.  Assessing and controlling the spread and the effects of common ragweed in Europe.  Contractor: Natural Environment Research Council, UK.  456 pp.

California Invasive Plant Council. http://cal-ipc.org

Consortium of California Herbaria. http://ucjeps.berkeley.edu/consortium

Encycloweedia. https://www.cdfa.ca.gov/plant/IPC/encycloweedia/encycloweedia_hp.html

Goplen, J.J., Sheaffer, C.C., Becker, R.L., Coulter, J.A., Breitenbach, F.R., Behnken, L.M., Johnson, G.A., and J.L. Gunsolus.  2016.  Giant ragweed (Ambrosia trifida) seed production and retention in soybean and field margins.  Weed Technology.  30: 246-253.

Megyeri, K.  2011.  The impact of Ambrosia trifida (giant ragweed) on native prairie species in an early prairie restoration project.  Thesis.  University of New Orleans.  Accessed from: http://scholarworks.uno.edu/cgi/viewcontent.cgi?article=1001&context=honors_theses

Webster, T.M., Loux, M.M., Regnier, E.E., and S.K. Harrison.  1994.  Giant ragweed (Ambrosia trifida) canopy architecture and interference studies in soybean (Glycine max).  Weed Technology.  8: 559-564


Author:

Kyle Beucke, 1220 N Street, Room 221, Sacramento, CA, 95814, 916-403-6741, plant.health[@]cdfa.ca.gov

Responsible Party:

Dean G. Kelch, Primary Botanist; California Department of Food and Agriculture; 1220 N Street, Sacramento, CA 95814; Tel. (916) 403-6650;  plant.health[@]cdfa.ca.gov.


Comment Period:* CLOSED

1/10/2018 – 2/24/2018


*NOTE:

You must be registered and logged in to post a comment.  If you have registered and have not received the registration confirmation, please contact us at plant.health[@]cdfa.ca.gov.


Comment Format:

♦  Comments should refer to the appropriate California Pest Rating Proposal Form subsection(s) being commented on, as shown below.

Example Comment:
Consequences of Introduction:  1. Climate/Host Interaction: [Your comment that relates to “Climate/Host Interaction” here.]

♦  Posted comments will not be able to be viewed immediately.

♦  Comments may not be posted if they:

Contain inappropriate language which is not germane to the pest rating proposal;

Contains defamatory, false, inaccurate, abusive, obscene, pornographic, sexually oriented, threatening, racially offensive, discriminatory or illegal material;

Violates agency regulations prohibiting sexual harassment or other forms of discrimination;

Violates agency regulations prohibiting workplace violence, including threats.

♦  Comments may be edited prior to posting to ensure they are entirely germane.

♦  Posted comments shall be those which have been approved in content and posted to the website to be viewed, not just submitted.


Pest Rating: B

 


Posted by ls

Tropical Whiteweed | Ageratum conyzoides L.

California Pest Rating  for
Tropical whiteweed | Ageratum conyzoides L.
Family:  Asteraceae
Pest Rating: C |  Proposed Seed Rating: None

 


PEST RATING PROFILE
Initiating Event:

Tropical whiteweed was intercepted in Yolo county in October 2017 (PDR 570P066111862). It has not yet been rated. A pest rating proposal is required to determine a permanent rating for this pest.

History & Status:

Background: Ageratum conyzoides L. (tropical whiteweed, billy goat weed) is an erect, 30 to 80 cm tall, annual herb with shallow, fibrous roots. The stem is cylindrical and is covered with short, white hairs; it becomes strong and woody with age. The leaves are pubescent with long petioles and they are arranged oppositely. The fruit is a ribbed or angled, black achene that had rough bristles with upward turning spines. Tropical whiteweed has great morphological variation, and appears highly adaptable to different ecological conditions. It is a common pantropical weed that can extend into subtropical and warm temperate zones, where it grows during the summer2.

Worldwide Distribution: Tropical whiteweed is native to South and Central America and probably also the West Indies. It is introduced in Asia, Africa, North America, Europe, and Oceania2.

United States: Tropical whiteweed is known from Connecticut, Georgia, Kentucky, Maryland, Mississippi, North Carolina, Alabama, California, Florida, Hawaii, Louisiana, and Missouri5.

 

California Distribution: Tropical whiteweed has not yet been detected officially in California. Only one voucher from San Diego County is submitted3.

Official Control : Tropical whiteweed is listed as a harmful organism in New Zealand 7.

California Interceptions: Tropical whiteweed was recently intercepted in Yolo County in October 2017 (PRD 570P066111862)6. It has previously been intercepted in California during nursery inspections (300P06 039955, 1317560) and a dog team intercept (340P06128213)6.

The risk Ageratum conyzoides (tropical whiteweed) would pose to California is evaluated below.

Consequences of Introduction:

1) Climate/Host Interaction: Tropical whiteweed is adapted to Central and South America and it would presumably thrive in similar climates. It may be able to establish in a very limited part of California. It receives a Low (1) in this category.

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: Tropical whiteweed does not require any one host, but grows wherever ecological conditions are favorable. It receives a High (3) in this category.

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: Tropical whiteweed reproduces by seed. It has no photoperiodic requirement for germination and in some areas one-half of the seeds will germinate shortly after they are shed. Each plant can produce up to 40,000 seeds that can be dispersed by wind and water. They may be dispersed longer distances by vehicles and in contaminated agricultural produce2, 4. It receives a High (3) in this category

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: Tropical whiteweed is considered to be an important weed of crops in the tropics and subtropics in open situations. Year-round flowering and the production of large quantities of seed allow it to compete with crops, which could lower the crop yield and value. It occurs in cultivated land, roadsides, and in forest edges. Tropical whiteweed is also an important alternate host for pathogens and nematode pests of various economically important crops. For example, it is a symptomless carrier of Burkholderia solanacearum, which is a bacterial pest of potato in India. It is a host of the banana nematodes Radopholus similis and Helicotylenchus multicinctus in Brazil and of the root knot nematode, Meloidogyne javanica, in many parts of the world. It is also the host of the Tomato Yellow Leaf Curl Tanzania Virus (TYLCTZV) and the Ageratum Yellow Vein Virus2. It receives a High (3) in this category.

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

Economic Impact:  A, B & E

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.

Economic Impact Score 3

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: Tropical whiteweed thrives best in rich, moist, mineral soils with high humidity and it tolerates shading. It is not tolerant to soils with poor fertility1.It is likely to trigger new chemical treatments by ranchers and land managers. It receives a Medium (2) in this category.

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

Environmental Impact:  D

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.

Environmental Impact: Score: 2

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 Ageratum conyzoides (tropical whiteweed): Medium (12)

Low = 5-8 points

Medium = 9-12 points

High = 13-15 points

6) Post Entry Distribution and Survey Information: Tropical whiteweed is not considered to be naturalized in California, as only one voucher from San Diego County has been submitted. It considered as localized distribution in California and Received 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: High (13)

Uncertainty:

Tropical whiteweed has only been documented from San Diego County and has been intercepted a couple of times. This weed has been growing in California for years and has not escaped; therefore, the uncertainty about this species is low.

Conclusion and Rating Justification:

Conclusions of the harm(s) associated with this pest to California using all of the evidence presented above: Proposed Rating: based on the score listed above the pest is a potential weed with a distribution in limited areas. A “C” rating is recommended, as the plant is invasive, but it is of limited adaptability in the dry climate of California.


References:
  1. Global Invasive Species database. Accessed October 20, 2017.  http://issg.org/database/species/ecology.asp?si=1493&fr=1&sts=&lang=EN
  2. Invasive Species Compendium: Distribution maps for plant pests, Accessed October 20, 2017.  http://www.cabi.org/isc/datasheet/3572
  3. Baldwin, B. G., D. H. Goldman, D. J. Keil, R. Patterson, T. J. Rosatti, and D. H. Wilken, editors. 2012. The Jepson manual: vascular plants of California, second edition. University of California Press, Berkeley. Accessed October 20, 2017.  http://ucjeps.berkeley.edu/cgi-bin/get_smasch_county.pl?taxon_id=771
  4. Pacific Island Ecosystem. Accessed October 20, 2017.  http://www.hear.org/pier/species/ageratum_conyzoides.htm
  5. Plant in USA.  Accessed October 20, 2017.  http://www.plantsinusa.com/show/plant/Ageratum-Conyzoides/2744
  6. Pest and Damage Record Database, California Department of Food and Agriculture, Plant Health and Pest Prevention Services. Accessed October 20, 2017.  http://phpps.cdfa.ca.gov/user/frmLogon2.asp
  7. USDA Phytosanitary Certificate Issuance & Tracking System (PCIT) Phytosanitary Export Database (PExD). Accessed October 20, 2017. https://pcit.aphis.usda.gov/pcit/

Author:

Javaid Iqbal,  California Department of Food and Agriculture; 1220 N Street, Sacramento, CA 95814; Tel. (916) 403-6695; plant.health[@]cdfa.ca.gov.

Responsible Party:

Dean G. Kelch, Primary Botanist; California Department of Food and Agriculture; 1220 N Street, Sacramento, CA 95814; Tel. (916) 403-6650;  plant.health[@]cdfa.ca.gov.


Comment Period:* CLOSED

1/5/18 – 2/19/18


*NOTE:

You must be registered and logged in to post a comment.  If you have registered and have not received the registration confirmation, please contact us at plant.health[@]cdfa.ca.gov.


Comment Format:

♦  Comments should refer to the appropriate California Pest Rating Proposal Form subsection(s) being commented on, as shown below.

Example Comment:
Consequences of Introduction:  1. Climate/Host Interaction: [Your comment that relates to “Climate/Host Interaction” here.]

♦  Posted comments will not be able to be viewed immediately.

♦  Comments may not be posted if they:

Contain inappropriate language which is not germane to the pest rating proposal;

Contains defamatory, false, inaccurate, abusive, obscene, pornographic, sexually oriented, threatening, racially offensive, discriminatory or illegal material;

Violates agency regulations prohibiting sexual harassment or other forms of discrimination;

Violates agency regulations prohibiting workplace violence, including threats.

♦  Comments may be edited prior to posting to ensure they are entirely germane.

♦  Posted comments shall be those which have been approved in content and posted to the website to be viewed, not just submitted.


Pest Rating: C |  Proposed Seed Rating: None

 


Posted by ls

Graceful Spurge | Euphobia hypericifolia

California Pest Rating  for
Graceful spurge | Euphorbia hypericifolia L.
Malpighiales: Euphorbiaceae
Pest Rating: A | Proposed Seed rating: N/A

 


PEST RATING PROFILE
Initiating Event:

This plant given a Q rating as a potential invasive weed on 11/2/2017 (PDR 19TPO6465546).

History & Status:

Graceful spurge (Euphorbia hypericifolia, synonym Chamaesyce hypericifolia) is an upright perennial herb with arching, openly branched flowering stems to 60 cm tall, but often low when mowed. The leaves are opposite, ovate, with small teeth. The flowers are small, even by spurge standards (0.5 – 1 mm) and are borne in dense heads in the axils of the upper leaves. Seeds are expelled forcefully from capsules up to 4 meters away. Cattle avoid foraging on spurge when possible, but goats and sheep are generally immune to its irritant properties and may develop a preference for it. It grows in disturbed areas, in evergreen woodland and in crop fields. It is also found in nurseries as a weed. The common horticultural container plant Euphorbia ‘Diamond Frost’ is sometimes attributed to Euphorbia hypericifolia. Nevertheless, it is not closely related to this species, nor is it weedy. Therefore, this attribution is in error and should not be used for regulatory action, regardless of labelling.

Official Control: Graceful spurge was just recently detected in recently imported nursery stock, and, although weedy, it is native to the southeastern U.S. So, there is no official control.

California Distribution:  It is not yet fully established in California, although it has been detected in weedy situations several times.

California Interceptions: Vouchered specimens are known from San Diego County as weeds.

United States: It is native to the Southeastern U.S.

International: Graceful spurge is native to the New World as a tropical to subtropical weed. It is introduced in warmer areas of the Old World.

This risk Carnation spurge would pose to California is evaluated below.

Consequences of Introduction: 

1) Climate/Host Interaction: The plant has adapted to warm, well-watered areas throughout the world, so it could spread widely as a nursery weed, but is not otherwise likely to spread except to irrigated situations. Graceful spurge receives a Low (1) 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: Graceful spurge produces via numerous seeds that are able to spread via nursery stock and other means. The seed bank is moderately persistent. Graceful spurge 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: Graceful spurge can lower nursery productivity, and require more intensive weed control activities in nurseries. If is escapes into horse paddocks and other irrigated pastures, it could poison livestock. Graceful spurge receives a High (3) in this category.

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

Economic Impact: A, B, D, F

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.

Economic Impact Score: 3

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: Graceful spurge is not likely to spread widely beyond disturbed, human-mediated landscapes, as California is too dry to favor its growth. Graceful spurge receives a Low (1) in this category.

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

Environmental Impact:

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.

Environmental Impact Score: 1

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 Graceful spurge: Medium (10)

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: Graceful spurge has been found in in several counties in California, but does not seem to be well established. 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 (10)

Uncertainty:

Graceful spurge has not yet widely established in California due to the paucity of appropriate habitat. Nevertheless, it has shown its ability to spread and thrive in similar climates to those it is found in in Florida as a nursery or garden weed. It could almost certainly do the same in California.

Conclusion and Rating Justification:

Graceful spurge is a significant nursery weed. It deserves an A rating as the nursery industry in California would be harmed by the establishment of this weed; its rarity in California raises the possibility of excluding it by timely regulation.


References:

Brunel S, G. Schrader, G. Brundu & G. Fried. 2010. Emerging invasive alien plants for the Mediterranean Basin. Bull OEPP/EPPO Bull. 40:219–238.

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.

Gregor T. & L. Meierott. 2013. Report 72. Euphorbia hypericifolia L. – P. 277. In: Vladimirov V., Dane F., Stevanovič V., & Tan K, eds. New floristic records in the Balkans: 22. Phytol Balcan.19: 267-303.

S. Sciandrello, S., G. Giusso del Galdo & P. Minissale. 2016. Euphorbia hypericifoliaL. (Euphorbiaceae), a new Alien Species for Italy. Webbia 71: 163-168.


Responsible Party:

Dean G. Kelch, Primary Botanist; California Department of Food and Agriculture; 1220 N Street, Sacramento, CA 95814; Tel. (916) 403-6650;  plant.health[@]cdfa.ca.gov.


Comment Period:* CLOSED

1/5/18 – 2/19/18


*NOTE:

You must be registered and logged in to post a comment.  If you have registered and have not received the registration confirmation, please contact us at plant.health[@]cdfa.ca.gov.


Comment Format:

♦  Comments should refer to the appropriate California Pest Rating Proposal Form subsection(s) being commented on, as shown below.

Example Comment:
Consequences of Introduction:  1. Climate/Host Interaction: [Your comment that relates to “Climate/Host Interaction” here.]

♦  Posted comments will not be able to be viewed immediately.

♦  Comments may not be posted if they:

Contain inappropriate language which is not germane to the pest rating proposal;

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♦  Comments may be edited prior to posting to ensure they are entirely germane.

♦  Posted comments shall be those which have been approved in content and posted to the website to be viewed, not just submitted.


Pest Rating: A | Proposed Seed rating: N/A

 


Posted by ls

Manchurian Wild Rice | Zizania latifolia

California Pest Rating  for
Machurian Wild Rice. Photo credit: National Institute of Water & Atmospheric Research (NIWA), New Zealand
Click on image for photo citation
Manchurian Wild Rice | Zizania latifolia
Pest Rating: A | Proposed Seed Rating: R

 


PEST RATING PROFILE

Initiating Event:

This plant was been detected in California in 2017.

History & Status:

Zizania latifolia is a large perennial grass growing to 3.5 m.  It is hardy in warm temperate and subtropical areas. It flowers from July to September, and the seeds ripen soon thereafter. The flowers are bisexual. It is adaptable to many soil types and can even grow in shallow water once established. Z latifolia typically grows in dense, long-lived stands on land and water margins, overtopping other riparian species. It is extremely tolerant of damage, grazing, cold or heat, wind, fire, different soil types, moderate shade and moderate salinity.

Although Z. latifolia was once grown in China as a grain crop, it is now almost exclusively grown as a vegetable. The swollen stem bases, infected with the smut fungus Ustilago esculenta, are eaten as a vegetable by the Chinese. They must be harvested before the fungus starts to produce spores, as the stems deteriorate once the smut reaches reproductive maturity.

Official Control: Z. latifolia has been eradicated in California and other states as it serves as a host to a fungus that could infect North American native wild rice species (e.g., Z. aquatica). Importation of the stems to the United States is prohibited in order to protect the North American Zizania from the fungus. A small plot of smut-infested Z. latifolia was discovered growing near Modesto, CA in 1991; it was destroyed to prevent the spread of the smut.

California Distribution:  Z. latifolia is not known to be naturalized in California, but it is being cultivated in Riverside County.

California Interceptions: Z. latifolia was recently submitted to CDFA from a cultivated field in Riverside County.

Worldwide Distribution: Z. latifolia is native to China, Northeastern India, Japan, Korea, Myanmar, and southern Russia where is grown as a vegetable. It is cultivated in Southeast Asia as well. It is naturalized in several other areas. It is unknown whether it is not invasive in these areas despite naturalization, or its invasiveness is ignored due to its long cultivation. Z. latifolia was accidentally introduced into New Zealand where it has become a serious wetland weed in the coastal zone of the North Island. It was also introduced into Hawaii, where it may not have persisted.

Consequences of Introduction: 

1) Climate/Host Interaction: Evaluate if the pest would have suitable hosts and climate to establish in California. The risk is Medium (2), as the plant could occur in wetlands in warmer areas. Areas such as the Delta as well as irrigation canals and watering ponds might be potential habitat for this plant 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: Evaluate the host range of the pest. Score: 3 The risk is High (3) as weeds do not require any one host, but grow wherever ecological conditions are favorable.

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 spreads vegetatively via rhizomes and produces numerous seeds. Under the right conditions it can spread rapidly in water. The seeds can spread on boats and equipment. Birds may also spread the seed.

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: If it invaded wet meadows (as in New Zealand) or rice fields, it could lower yields and choke out desired plants. It can grow in irrigation ditches and reduce water delivery and access. The swollen stem bases, infected with the smut fungus Ustilago esculenta, are eaten as a vegetable by the Chinese. There is concern that esculenta could spread from Z. latifolia to native North American species of Zizania (e.g., Z. aquatica) that produce commercial wild rice. Z. aquatica is not native to California, but over 16,000 acres of wild rice was grown in California in 2006, making it the largest producer of wild rice in the world.

Economic Impact 4: A, D, E, & G.

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.

The potential Economic Impact is High (3):

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: Under favorable circumstances, latifolia forms permanent stands along water margins and moist meadows of nothing but Zizania latifolia, replacing all other species. It can increase siltation, altering water systems, increase the impact of flooding and destroying habitat for aquatic fauna and flora. The impact is potentially High (3).

Environmental Impact 3: A, C, & D

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.

Environmental Impact Score: 3

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 Zizania latifolia:

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

Low = 5-8 points

Medium = 9-12 points

High = 13-15 points

6) Post Entry Distribution and Survey Information: 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.
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 score: High (14)

Uncertainty:

There is moderate uncertainty, as the plant has established and become invasive in New Zealand, but similar conditions occur in limited areas of California. It is native to eastern Asia and widely naturalized beyond its natural range, yet it is not cited as a weed of rice paddies despite being seemingly well adapted to these conditions.

Conclusion and Rating Justification:

A potentially significant weed in CA of both natural wetlands, wet crop lands and irrigation canals. It is also a carrier of a fungus that could attack and seriously reduce productivity of wild rice. Despite some uncertainty, an A rating is justified given the potential risks.


References:

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

CDFA Pest Damage Report 331PO6200067 dated 10/19/2017.

CDFA Pest Damage Report 331PO6200069 dated 10/20/2017.

Chen, S., Li, D., Zhu, G., Wu, Z., Lu, S., Liu, L., et al. 2006. Zizania in Flora of China, Vol. 22. Z. Y. Wu & P. H. Raven eds. Beijing; St. Louis, MO: Science Press, Missouri Botanical Garden Press. Pp. 186–187.

Duke, J. A. 1983. Handbook of Energy Crops: Zizania aquatica L. Accessed online 11/9/2017: https://www.hort.purdue.edu/newcrop/duke_energy/Zizania_aquatica.html

Larkcom J. Oriental Vegetables John Murray 1991 ISBN 0-7195-4781-4

Global Invasive Species Database. Species profile: Zizania latifolia. Accessed on on 11/8/2017:  http://www.iucngisd.org/gisd/species.php?sc=866

Ohwi, J. 1984. Flora of Japan. F. G. Meyer & E. G. Walker, eds. Smithsonian Institution Press. Washington, D.C.

Tanaka. T. Tanaka’s Cyclopaedia of Edible Plants of the World. Keigaku Publishing 1976

Terrell, E. E. & L. R. Batra. 1982.  Zizania latifolia and Ustilago esculenta, a grass-fungus association. Economic Botany 36: 274–85.

Wagner, W. L. D. R Herbst and S. H. Sohmer. 1999. Manual of the Flowering Plants of Hawai`i, Volume 1. University of Hawai’i and Bishop Museum Press. Honolulu, HI.

Weedbusters Plant Profile: Manchurian Wild Rice. Accessed 11/8/2017: http://www.weedbusters.org.nz/weed-information/zizania-latifolia/59/

Photo credit: National Institute of Water & Atmospheric Research (NIWA), New Zealand


Responsible Party:

Dean G. Kelch, Primary Botanist; California Department of Food and Agriculture; 1220 N Street, Sacramento, CA 95814; Tel. (916) 403-6650;  plant.health[@]cdfa.ca.gov.


Comment Period:* CLOSED

1/5/18 – 2/19/18


*NOTE:

You must be registered and logged in to post a comment.  If you have registered and have not received the registration confirmation, please contact us at plant.health[@]cdfa.ca.gov.


Comment Format:

♦  Comments should refer to the appropriate California Pest Rating Proposal Form subsection(s) being commented on, as shown below.

Example Comment:
Consequences of Introduction:  1. Climate/Host Interaction: [Your comment that relates to “Climate/Host Interaction” here.]

♦  Posted comments will not be able to be viewed immediately.

♦  Comments may not be posted if they:

Contain inappropriate language which is not germane to the pest rating proposal;

Contains defamatory, false, inaccurate, abusive, obscene, pornographic, sexually oriented, threatening, racially offensive, discriminatory or illegal material;

Violates agency regulations prohibiting sexual harassment or other forms of discrimination;

Violates agency regulations prohibiting workplace violence, including threats.

♦  Comments may be edited prior to posting to ensure they are entirely germane.

♦  Posted comments shall be those which have been approved in content and posted to the website to be viewed, not just submitted.


Pest Rating: A | Proposed Seed Rating: R

 


Posted by ls

Prickly Acacia | Vachellia Nilotica

California Pest Rating  for
By J.M.Garg (Own work) [GFDL (http://www.gnu.org/copyleft/fdl.html) or CC BY-SA 3.0 (https://creativecommons.org/licenses/by-sa/3.0)], via Wikimedia Commons

Click on image for photo citation

Vachellia nilotica:  Prickly acacia
Solanales: Febaceae (Caesalpinioideae)
Pest Rating: A | Proposed Seed Rating: P

 


PEST RATING PROFILE
Initiating Event:

Vachellia (Acacia) nilotica is a federal noxious weed and is one of the 20 worst weeds in Australia because of its invasiveness, potential to spread, economic and environmental impacts. This invasive weed is currently not present in California but the climate conditions in the state are favorable for its growth and establishment. There is currently no pest rating designated for V. nilotica. A pest rating proposal is needed to assign a permanent rating.

History & Status:

Background: Vachellia nilotica (L.) P.J.H. Hurter & Mabb. is a medium sized tree that can reach a height of 10 m. The crown is flat or round and branches can droop downward. Young branches are smooth and grey to brown in color. Leaves are twice compound. The flowers are yellow, borne in small heads 1 cm in diameter and appear from September to January depending upon the rainy season. Pods are flat, straight or slightly curved, are fleshy when young with reddish hairs and are deeply constricted between each seed; they do not split but break open. This species occurs in wooded grassland and scrub escarpment, low lying forests, in deep soil and along rivers (South Africa National Biodiversity Institute, 2005).

Vachellia nilotica was introduced in Australia as a source of gum arabic and was cultivated as a fodder and shade plant for livestock in semi-arid pastures. It is also grown as garden ornamental in drier inland areas in Australia (Environmental Weeds of Australia, 2016).

Vachellia nilotica prefers semi-arid, warmer temperate, and sub-tropical regions but is also found in tropical environments and will grow near water sources in arid areas. It is most commonly found growing in grasslands, pastures and open woodlands. Within these plant communities it inhabits floodplains, open plains, gullies, areas near waterways (i.e. creeks and streams) and areas near other water sources (i.e. dams and bores). It also grows on recently cleared land, near stockyards and farm buildings, and along roadsides. (Environmental Weeds of Australia, 2016).

Worldwide DistributionVachellia nilotica is native to the arid and semi-arid regions of Africa and western Asia, the Indian sub-continent (i.e., India, Pakistan, and Myanmar) and the Arabian peninsula (i.e., Oman and Yamen). It has been introduced in China, Australia, the Caribbean, Indian Ocean islands, Mauritius, the United States, Central America, South America and the Galápagos Islands. It has naturalized in several countries where it has been introduced as a medicinal, forage and fuelwood plant (GRIN Database).

In the United States, it has been introduced in Arizona, California and Florida, Puerto Rico and Virgin Islands in the past. (Scher et.al, 2015).It has been introduced in China, Australia (in Northern Territory and Queensland where it is considered to be a pest plant of national importance), the Caribbean, Indian Ocean islands, Mauritius, the United States, Central America, South America and the Galápagos Islands. It has naturalized in several countries where it has been introduced as a medicinal, forage and fuelwood plant. It has been introduced in China, Australia (in Northern Territory and Queensland where it is considered to be a pest plant of national importance), the Caribbean, Indian Ocean islands, Mauritius, the United States, Central America, South America and the Galápagos Islands. It has naturalized in several countries where it has been introduced as a medicinal, forage and fuelwood plant.

 Official Control: Vachellia nilotica is a federal noxious weed (Federal Noxious Weed Regulations, 2010) and is listed as a harmful organism in French Polynesia, Honduras and New Zealand (PCIT-PExD).

California Distribution: Vachellia nilotica is not found growing in the natural environment in California.

California InterceptionsVachellia nilotica has never been intercepted by CDFA through any detection activities (border stations, high risk pest exclusion, detection surveys etc.).

The risk Vachellia nilotica (prickly acacia) would pose to California is evaluated below.

Consequences of Introduction: 

1) Climate/Host Interaction: Vachellia nilotica has the ability to grow in warm deserts, the south coast area of California is a possible habitat as these areas provide warmer and near tropical environments for its growth. However, the risk of invasion is high in near tropical areas where there are both good water supply to promote high seed production and presence of livestock to disperse seeds. It receives a Medium (2) 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) Known Pest Host Range: Weeds do not need one host but grow wherever ecological conditions are favorable. Vachellia nilotica receives a High (3) in this category.

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: Vachellia nilotica reproduces mainly by seed. It flowers in 3-4 years in ideal conditions. Mature tree can produce 200-3000 pods, each pod carrying 8-16 seeds. Seed production is higher during wet years where trees are close to water channels (Carter, 1998). Seeds are dispersed by large herbivores like cattle and sheep. Transportation of livestock that have ingested seeds can lead to dispersal over long distance. Seeds can also spread by water, particularly during floods after heavy rains and by mud adhering to legs of animals or vehicles. Strong winds can also carry seeds pods over short distances (Environmental Weeds of Australia, 2016). Vachellia nilotica 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: The spread of Vachellia nilotica trees can reduce the amount of available pasture for livestock. Dense thickets of V. nilotica trees can restrict access, impede the movement of vehicles and livestock, and may even reduce land values. Irrigation systems can become more expensive to operate because the tree can use some of the water (CABI 2017). Being a federal noxious weed and if it were to establish in California, it could impact international trade. (USDA APHIS Weed Risk Assessment). It receives a (High) in this category.

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

Economic Impact: A, C, G

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.

Economic Impact Score: 3

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:  Vachellia nilotica can outcompete pasture grasses for water in open forest and woodlands, and grasslands. Such losses of groundcover can facilitate water and wind erosion and leads to soil degradation. Serious invasion by this species can heavily disrupt natural communities. Approximately seven million hectares of the Mitchell grass plains in northern Australia have been infested by V. nilotica. Establishment of this species can cause a significant change in vegetation structure and can threaten the integrity and biodiversity of grassland communities. Changes in vegetation can pose a threat to survival of endangered species in these areas (Environmental Weeds of Australia, 2016). It receives a High (3) in this category.

Environmental Impact: A, B, C

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 Vachellia nilotica (prickly acacia): High (13)

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: Vachellia nilotica has never been found in the environment and receives a Not established (0) 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: High (13).

Uncertainty:

Vachellia nilotica is a listed as a federal noxious weed that may be introduced to California for cultivation as a fodder and shade plant for livestock in pasture areas and also as garden ornamentals in the inland areas. Because this species is economically useful, introduction can be possible through international transport by passengers. There are nine species in the Vachellia nilotica species complex; this can make it difficult to identify. Early detection surveys can confirm the presence of Vachellia nilotica. Since it has not established in California, its ability to invade the warm, dry areas of California is unknown.

Conclusion and Rating Justification:

Vachellia nilotica has not been found in the natural environment of California. If this species were to be cultivated deliberately or if introduced accidently, it could cause significant economic and environmental impacts. Therefore, as it is not yet established in California and invasion is possible, an “A” rating is justified.


References:

CABI, 2017. Acacia nilotica. In: Invasive Species Compendium. Wallingford, UK: CAB International. Accessed 10/11/2017

http://www.cabi.org/isc/datasheet/2342

CARTER, J. O. 1998. 7.2 Acacia nilotica: A tree legume out of control. Pp. 338–351 in H. M. Shelton and R. C. Gutteridge (eds.), Forage tree legumes in tropical agriculture. Tropical Grassland Society of Australia, St. Lucia, Queensland. Accessed 10/12/2017

https://www.cabdirect.org/cabdirect/abstract/19940601700

Environmental Weeds of Australia for Biosecurity Queensland 2016. Vachellia nilotica

Accessed 10/12/2017.

https://keyserver.lucidcentral.org/weeds/data/media/Html/vachellia_nilotica.pdf

Germplasm Resources Information Network (GRIN) Database 2015. Vachellia Nilotica (L.) P.J.H. Hurter & Mabb. Accesses 10/11/2017

https://npgsweb.ars-grin.gov/gringlobal/taxonomydetail.aspx?465206

Phytosanitary Certificate Issuance & Tracking System (PCIT), Phytosanitary Export Database (PExD), USDA, APHIS. Accessed 10/10/2017

https://pcit.aphis.usda.gov/PExD/faces/ReportFormat.jsp

South African National Biosecurity Institute 2005. Biodiversity of Life. Vachellia nilotica subsp. Kraussiana. Accessed 10/10/2017

http://pza.sanbi.org/vachellia-nilotica-subsp-kraussiana

Scher, J. L., D. S. Walters, and A.J. Redford. 2015. Federal noxious weed disseminules of the U.S., Edition 2.2. California Department of Food and Agriculture, and USDA APHIS Identification Technology Program. Fort Collins, CO. [10/11/2017]

http://idtools.org/id/fnw/factsheet.php?name=14575

Update of Federal Noxious Weed Regulations 2010. A Rule by USDA Animal and Plant Health Inspection Services.

https://www.federalregister.gov/documents/2010/11/10/2010-28346/update-of-noxious-weed-regulations

Weed Risk Assessment for Acacia Nilotica (L.) Willd. Ex Delile. Version 6, June 2, 2009. USDA Animal and Plant Health Inspection Services. National Weed Program Risk Assessment.

https://www.aphis.usda.gov/plant_health/plant_pest_info/weeds/downloads/wra/AniloticaWRA.pdf


Author:

Raj Randhawa, 1220 ‘N’ Street, Room 221, Sacramento CA 95814, (916) 654-0317, plant.health[@]cdfa.ca.gov

Responsible Party:

Dean G. Kelch, Primary Botanist; California Department of Food and Agriculture; 1220 N Street, Sacramento, CA 95814; Tel. (916) 403-6650; plant.health[@]cdfa.ca.gov.


Comment Period:* CLOSED

1/4/18 – 2/18/18


*NOTE:

You must be registered and logged in to post a comment.  If you have registered and have not received the registration confirmation, please contact us at plant.health[@]cdfa.ca.gov.


Comment Format:

♦  Comments should refer to the appropriate California Pest Rating Proposal Form subsection(s) being commented on, as shown below.

Example Comment:
Consequences of Introduction:  1. Climate/Host Interaction: [Your comment that relates to “Climate/Host Interaction” here.]

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♦  Comments may not be posted if they:

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Pest Rating: A | Proposed Seed Rating: P

 


Posted by ls

 

 

Jewels of Opar/Fameflower | Talinum Paniculatum

Jewels of Opar/Talinum paniculatum | Photo by Ronggy
California Pest Rating for
Jewels of opar / Fameflower | Talinum paniculatum
 Family:  Portulacaceae
Pest Rating: C | Proposed Seed Rating: None

 


PEST RATING PROFILE
Initiating Event:

Jewels of opar was intercepted for the first time at the Needles border station in July 2017 (PRD NE0P06655879); this plant has not yet been rated. A pest rating proposal is required to determine a permanent rating for this pest.

History & Status:

Background:  Talinum paniculatum (jewels of opar or fameflower) is a fleshy, shrubby, erect, glabrous, herbaceous plant from the purslane family (Portulacaceae) that grows up to 120 centimeters tall. Jewels of opar is probably the most widespread species of the genus, as it is frequently encountered as a weed. The small, delicate, pink flowers in cloudlike panicles contrast attractively with the golden yellow, round seed capsules and are produced almost year-round. The leaves are glossy and bright green; they are sometime used as a vegetable1.

Worldwide Distribution: Jewels of opar is native to tropical America, but is now a pantropical weed. It occurs as an adventive scattered throughout tropical Africa, and is locally cultivated in Ghana and Nigeria4. Jewels of opar is also reported from Mexico, the West Indies, Central America, South America, and the southern United States. It was introduced to central Argentina, central Africa, and southern Asia2.

United States:  Jewels of opar is known from Arizona, New Mexico, Texas, Louisiana, Kentucky, North Carolina, South Carolina, Georgia, and Florida2. It is generally thought to be native to the southwest and adventive eastward, where it is often weedy1, 3.

California Distribution: Jewels of opar has not yet been detected in California, although it known to occur as greenhouse weed4.

Official Control: Jewels of opar is not considered to be a noxious weed by any State government authorities5.

California Interceptions: Jewels of opar was recently intercepted at the Needles border station in July 2017 in a shipment from Texas (PRD NE0P06655879)4.

The risk Talinum paniculatum (Jewels of opar) would pose to California is evaluated below.

Consequences of Introduction:

1) Climate/Host Interaction: Jewels of oparis adapted to central and southern America and it would presumably thrive in similar climates. It may be able to establish in limited part of California but it does not seem to tolerate the summer drought found in most of CA. It receives a Low (1) in this category.

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: Jewels of opardoes not require any one host, but grows wherever ecological conditions are favorable. It receives a High (3) in this category.

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: Jewels of opar reproduces by seed and stem cutting. The seeds are small (1 mm long), have a lenticular to comma-shape, and are produced in large numbers. There are about 5000 seeds per gram3. These seeds could be dispersed short distances by foraging animals, human activity, or by wind. They may be dispersed longer distances by vehicles and in contaminated agricultural produce. It receives a Medium (2) in this category

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: Jewels of oparis considered to be a pantropical weed, but its invasiveness is not addressed in literature. It occurs in cultivated land, roadsides, and in forest edges. It rarely, if ever grows in dense stands, but can seed around grasslands in moist hot summer areas. It can be nuisance weed in greenhouses. It receives a Low (1) in this category.

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

Economic Impact:  D

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.

Economic Impact Score 1

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: Jewels of oparhas not yet naturalized in California, although it is common in heated greenhouses, especially those devoted to cacti & succulents. It receives a Low (1) in this category.

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

Environmental Impact:  

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.

Environmental Impact: Score: 1

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 Talinum paniculatum (Jewels of opar): Low (8)

Low = 5-8 points

Medium = 9-12 points

High = 13-15 points

6) Post Entry Distribution and Survey Information: Jewels of oparhas never been documented as naturalized in California and receives a Not Established (0) 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: Low (8)

Uncertainty:

Jewels of opar has never been documented as naturalized in California but it was recently intercepted at the CDFA Needles Inspection Station. The environment of California is not new for this weed. It has been in greenhouses in CA for years and has not escaped; therefore, the uncertainty about this species is low.

Conclusion and Rating Justification:

Nevertheless, it can be nuisance weed in greenhouses and should be include in nursery cleanliness standards. Conclusions of the harm(s) associated with this pest to California using all of the evidence presented above: Proposed Rating: based on the score listed above the pest is a low risk weed. A C” rating is recommended.


References:
  1. Encyclopedia of living forms. LLife, Online. Accessed August 7, 2017. http://www.llifle.com/Encyclopedia/SUCCULENTS/Family/Portulacaceae/32895/Talinum_paniculatum
  2. Flora of North America,     Accessed August 7, 2017.    http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=200007021
  3. Philippine Medicinal Plants.    Accessed August 7, 2017. http://www.stuartxchange.org/Talinum.html
  4. Plantnet online.  Accessed August 7, 2017. http://uses.plantnet-project.org/en/Talinum_paniculatum_(PROTA)
  5. Pest and Damage Record Database, California Department of Food and Agriculture, Plant Health and Pest Prevention Services. Accessed August 7, 2017.  http://phpps.cdfa.ca.gov/user/frmLogon2.asp
  6. USDA Phytosanitary Certificate Issuance & Tracking System (PCIT) Phytosanitary Export Database (PExD). Accessed August 7, 2017. https://pcit.aphis.usda.gov/pcit/

Author:

Javaid Iqbal,  California Department of Food and Agriculture; 1220 N Street, Sacramento, CA 95814; Tel. (916) 403-6695; plant.health[@]cdfa.ca.gov.

Responsible Party:

Dean G. Kelch, Primary Botanist; California Department of Food and Agriculture; 1220 N Street, Sacramento, CA 95814; Tel. (916) 403-6650; plant.health[@]cdfa.ca.gov.


Comment Period:* CLOSED

12/5/17 – 1/19/18


*NOTE:

You must be registered and logged in to post a comment.  If you have registered and have not received the registration confirmation, please contact us at plant.health[@]cdfa.ca.gov.


Comment Format:

♦  Comments should refer to the appropriate California Pest Rating Proposal Form subsection(s) being commented on, as shown below.

Example Comment:
Consequences of Introduction:  1. Climate/Host Interaction: [Your comment that relates to “Climate/Host Interaction” here.]

♦  Posted comments will not be able to be viewed immediately.

♦  Comments may not be posted if they:

Contain inappropriate language which is not germane to the pest rating proposal;

Contains defamatory, false, inaccurate, abusive, obscene, pornographic, sexually oriented, threatening, racially offensive, discriminatory or illegal material;

Violates agency regulations prohibiting sexual harassment or other forms of discrimination;

Violates agency regulations prohibiting workplace violence, including threats.

♦  Comments may be edited prior to posting to ensure they are entirely germane.

♦  Posted comments shall be those which have been approved in content and posted to the website to be viewed, not just submitted.


Pest Rating: C | Proposed Seed Rating: None


Posted by ls

Turkey Berry | Solanum torvum

California Pest Rating for
Turkey Berry |  Solanum torvum
Solanales: Solanaceae
Pest Rating: C |  Proposed Seed Rating: N/A

 


PEST RATING PROFILE
Initiating Event:

Solanum torvum was recently intercepted by Los Angeles County Agricultural commissioner’s office at Long beach on 7/20/2017. Molecular analysis has confirmed the identification of this species on 8/11/2017. This invasive weed has been given a temporary Q rating. A pest rating is required to assign a permanent rating for this species.

History & Status:

Background: Solanum torvum is an evergreen, multi-branched shrub or small tree that grows to 16 feet high. Leaves bear star shaped (stellate) hairs and scattered, flattened, broad-based, straight to slightly hooked prickles. Fruits are globose to ovoid, about half an inch wide and borne in erect clusters. Each fruit contains about 200 seeds (FDACS). The root system includes a deep and strong woody taproot with numerous woody laterals. Solanum torvum grows in a wide range of habitats throughout the tropics and the subtropics. It grows best in warm, moist, fertile conditions but once established it can withstand drought by shedding its leaves (CABI 2016). It is cultivated for its edible fruits that are eaten when immature (Langland and Burks, 1998)

Solanum torvum invades human disturbed open sites and is a major weed in pastures, roadsides, wastelands and plantations. It prefers moist, fertile soil but can also tolerate draught. It can form dense thickets in disturbed areas such as vacant lots, brushy pastures, recently abandoned farms, landslides and river banks; it is considered a weed in Florida, Hawaii, Papua New Guinea, French Polynesia and Tonga (Wagner et-al. 1999)

Worldwide Distribution:  Solanum torvum is native to the Antilles (Wagner et al. 1999). Langeland and Burks (1998) report that S. torvum is native from Mexico to Peru and Venezuela, and in the West Indies and Bermuda where it occurs in wet thickets, dry brushy plains, woodland clearings, and rocky hillsides. It is cultivated throughout the world for its edible fruits (Wagner et al. 1999) and has become a pantropical weed. S. torvum is reported as a weed in Florida, Hawaii, Australia, French Polynesia, Tonga, Samoa, Papua New Guinea, and elsewhere (PIER 2003, PLANTS 2003).

Official Control: Solanum torvum is reported as a harmful weed in China, Fiji, French Polynesia, Israel, Republic of Korea and Peru (PCIT-PExD). In the U.S., it is a federal noxious weed. This species has been listed as a noxious weed in Alabama, Florida, Hawaii, Minnesota, North Carolina, Vermont, Massachusetts, South Carolina, Oregon and California (USDA- NRCS)

California DistributionSolanum torvum has not been found growing in the natural environment of California.

California InterceptionsSolanum torvum was intercepted seven times between January 1, 1990 and August 22, 2017 by CDFA’s high risk inspections, dog teams, and project survey for weeds.  Most of the interceptions have been in shipments from Florida.

The risk Solanum torvum (turkey berry) would pose to California is evaluated below.

Consequences of Introduction: 

1) Climate/Host Interaction: Solanum torvum has established as a weed in the tropics of Florida and Hawaii. Since this species predominantly dominates human disturbed open sites and is rarely found on naturally disturbed sites (Nature Serve Explorer 2017), it has a limited potential of becoming established in sub-tropical areas in southern California and the central coast. Solanum torvum receives a Low (1) 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) Known Pest Host Range:  Solanum torvum does not require one particular host, but grows wherever ecological conditions are favorable. Even though it can grow and establish in disturbed and open areas, it might grow poorly in the lower humidity environment of California. This species cannot survive under closed forest canopy areas (PIER (Pacific Islands Ecosystems at Risk). It receives a Low (1) in this category.

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: Solanum torvum reproduces solely by seeds. Seedlings establish their roots quickly and become woody. Pollination is by insects. The seeds are spread by fruit eating birds and bats as well as by construction machinery and contaminated soil (CABI: Datasheet: Solanum torvum). This species was initially introduced to many areas through cultivation of its edible fruit. Unless introduced to California through cultivation, it is not likely to spread and get established. It 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: Solanum torvum is an invasive weed of pastures, roadsides and open native vegetation. It is also found in cassava and other perennial crops not exposed to cultivation (CABI) and can potentially reduce yield of these crops. None of these crops are grown in California. If this species were to establish in CA, use of various control methods could increase crop production costs. torvum is potentially poisonous to animals and possibly carcinogenic to humans. (Cuda and Parker et. al 2002). S. torvum is resistant to Meloidogyne spp and is used as a rootstock for grafting tomatoes in susceptible areas. Its resistance to Pseudomonas solanacearum and phomopsis fruit rot has also been reported (CABI). It receives a Medium (2) in this category.

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

Economic Impact: B, F

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.

Economic Impact Score: 2

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: Establishment of Solanum torvum can impact native biodiversity in the wet tropics due to its ability to form large, impenetrable thickets that can displace native species and alter vegetation structure in formerly open areas. However, it is also possible that its impact will not increase in future. (Nature Serve 2017). It receives a Medium (2) in this category.

Environmental Impact: A

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: 2

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 Solanum torvum (turkey berry): Low (8)

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: Solanum torvum has never been found in the environment and receives a Not established (0) 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: Low (8)

Uncertainty:

Solanum torvum is a federal noxious weed that may be introduced to California, as it is cultivated in certain parts of the world for its edible fruit. If introduced either through cultivation or by artificial means, it is less likely to spread to open, disturbed and abandoned farm land, pastures and riverbanks because of limited availability of water in California. Presence of similar Solanum species can complicate identification; however, early detection surveys in California can confirm the presence and possibly eradication this species if it were found in a small area. Wet tropical weeds can become nursery or row crop weeds in CA, but this is not common.

Conclusion and Rating Justification:

Solanum torvum (turkey berry) has never been found in the environment of California; it is less likely to have a significant economic and environmental impact if it were to enter the state. Nevertheless, it could be invasive in limited, irrigated areas & it is a federal noxious weed. Therefore a “C” rating is justified.


References:

Solanum Torvum – UF/IFAS Center for Aquatic and Invasive species, Florida Department of Agriculture and Natural Resources (FDACS)

http://www.freshfromflorida.com/Divisions-Offices/Plant-Industry/Bureaus-and-Services/Bureau-of-Entomology-Nematology-Plant-Pathology/Botany/Noxious-Weeds/Solanum-torvum-turkeyberry

Center for Agriculture and Biosciences International (CABI) Datasheet: Solanum Torvum (turkey berry).

http://www.cabi.org/isc/datasheet/50559

Cuda, J.P., Parker, P.E. and Coon, B.R. et al. 2002. Evaluation of exotic Solanum spp. (Solanales: Solanaceae) in Florida as host plants for the leaf beetles Leptinotarsa defecta & L. Texan (Coleoptera: Chrysomelidae). Florida Entomologist. 85(4): 599-610.

Langeland, K.A. and K.C. Burks. 1998. Identification and Biology of Non-Native Plants in Florida’s Natural Areas. University Press of Florida, Gainesville, FL. Nature Serve Explorer 2017. Solanum torvum

http://explorer.natureserve.org/servlet/NatureServe?searchName=Solanum+torvum

PIER (Pacific Islands Ecosystems at Risk). 2002. Invasive Plant Species: Solanum torvum. Available: http://www.hear.org/pier

PLANTS (National Plants Database). 2003. Online database. United States Department of Agriculture (USDA), Natural Resources Conservation Services (NRCS), National Plant Data Center, Baton Rouge, LA. Available: https://plants.usda.gov/core/profile?symbol=SOTO4

Pest and Damage Report Database, Plant Health And Pest Prevention Services, California Department of Food and Agriculture.

http://phpps.cdfa.ca.gov/index.asp

Starr, Forest, Starr Kim and Lloyd Loope, April 2013, United States Geological Survey—Biological Resources Division, Haleaka Field Station, Maui, Hawaii

Swarbrick, John T. 1997. Weeds of the Pacific Islands. Technical paper no. 209. South Pacific Commission, Noumea, New Caledonia.

USDA Phytosanitary Certificate Issuance & Tracking System (PCIT) –Phytosanitary Export Database (PExD). Harmful organism by country and commodity report- Solanum torvum. https://pcit.aphis.usda.gov/PExD/faces/PExDReport.jsp

Wagner, Warren L. /Herbst, Derral R. /Sohmer, S. H. 1999. Manual of the flowering plants of Hawaii. Revised edition. Bernice P. Bishop Museum special publication. University of Hawai‘i Press/Bishop Museum Press, Honolulu.


Author:

Raj Randhawa, California Department of Food and Agriculture

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

12/01/17 – 1/15/18


*NOTE:

You must be registered and logged in to post a comment.  If you have registered and have not received the registration confirmation, please contact us at plant.health[@]cdfa.ca.gov.


Comment Format:

♦  Comments should refer to the appropriate California Pest Rating Proposal Form subsection(s) being commented on, as shown below.

Example Comment:
Consequences of Introduction:  1. Climate/Host Interaction: [Your comment that relates to “Climate/Host Interaction” here.]

♦  Posted comments will not be able to be viewed immediately.

♦  Comments may not be posted if they:

Contain inappropriate language which is not germane to the pest rating proposal;

Contains defamatory, false, inaccurate, abusive, obscene, pornographic, sexually oriented, threatening, racially offensive, discriminatory or illegal material;

Violates agency regulations prohibiting sexual harassment or other forms of discrimination;

Violates agency regulations prohibiting workplace violence, including threats.

♦  Comments may be edited prior to posting to ensure they are entirely germane.

♦  Posted comments shall be those which have been approved in content and posted to the website to be viewed, not just submitted.


Pest Rating: C |  Proposed Seed Rating: N/A


Posted by ls

Giant Reed | Arundo donax

California Pest Rating for
Giant Reed | Arundo donax
Family: Poaceae
Pest Rating: B  | Proposed Seed Rating: R

 


PEST RATING PROFILE
Initiating Event:

There have been queries about growing tracts of giant reed in CA for use in biofuel production.

History & Status:

Background: Arundo donax is a tall, erect, perennial cane or bamboo-like grass, 2 to 8 meters high. It is one of the largest of the herbaceous grasses. The fleshy, almost bulbous, creeping root stocks form compact masses from which arise tough, fibrous roots that penetrate deeply into the soil. The culms reach a diameter of 1 to 4 cm and commonly branch during the second year of growth. These culms are hollow, with walls 2 to 7 mm thick and divided by partitions at the nodes. The nodes vary in length from 12 to 30 cm. The leaves are conspicuously two-ranked, 5 to 8 cm broad at the base and tapering to a fine point. The bases of the leaves are cordate and more or less hairy-tufted, persisting long after the blades have fallen. There can be variability in leaf and cane dimensions within a stand, possibly in response to water availability. Arundo donax was widely planted in the 19th century in CA for its bamboo-like stems. It’s planting was actively promoted in the 1950s by the USDA for use in erosion control along stream banks.

Arundo donax has been nominated as one of the top 100 Worst Invaders of the World by the Invasive Species Specialist Group of the World Conservation Union (http://www.issg.org). It was first introduced to the United States by Spanish colonists in the 1700’s and introduced again to California in the early 1800’s for erosion control in drainage canals. It is now a major invasive threat to riparian areas in California, as well as other southwestern states and it is listed as one of the twenty most invasive weeds in California and as a noxious weed in Texas.

Large infestations of Arundo donax are difficult to eradicate given that all

rhizomes must be removed or killed to prevent re-sprouting. This can cost from $7000-$25000 per acre, depending on difficulty of access. Typically a combination of mechanical removal and application of a systemic herbicide (e.g., glyphosate) provide the best control. Care must be taken to ensure that removed plant material does not sprout. Research on the biological control of Arundo donax in the United States has led to the recent release of a wasp, Tetramesa romana Walker (Hymenoptera: Eurytomidae), but its effects on population levels of Arundo donax are currently unknown .

 Worldwide Distribution: Arundo donax is native to many tropical to warm temperate regions from northern Africa and the Middle East eastwards through eastern and southeastern Asia (CABI, 2011a). It has been introduced into similar climates around the world in southern Europe, Central America, South America, and the Caribbean. It is invasive in southern Africa, the western United States, southern Europe, and the Azores (Weber, 2003).

California Distribution: Arundo donax is found along waterways throughout much of CA as far north as southern Humboldt County. It is missing from Northeastern CA, the high mountains, and it is rare in the desert region (Consortium of California Herbaria).

California Interceptions: Arundo donax is occasionbally sold in nurseries in CA and has been detected during nursery surveys.

This risk Arundo donax would pose to California is evaluated below.

Consequences of Introduction:

1) Climate/Host Interaction: The risk of Arundo donax is High (3) as illustrated by the broad distribution of the pest in California and its spread over the last 100 years.

-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.  Arundo donax does not require any one host, but grows wherever ecological conditions are favorable. It receives a High (3) in this category.

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

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: Arundo donax is a plant that spreads via water flow and human dispersal from rhizomes or stem fragments. It does not reproduce from seed in North America. The Risk is Medium (2).

Evaluate the 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) as Arundo donax only occasionally invades agricultural land. It can lower yields in some ranching systems, where Arundo donax blocks access to water. Although Arundo donax was once recommended for stream bank stabilization, its shallow roots mean that bank undercutting is frequent in Arundo donax infestations. Bridge and levee damage or failure have been partially ascribed to dense Arundo donax stands, due to flow conveyance loss.

Evaluate the economic impact of the pest to California using these criteria: Economic Impact: B, G 

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.

Economic Impact Score: 2

-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) in California, as Arundo donax is an ecological transformer, it excludes native riparian species, leads to unshaded streams detrimental to migratory fish stocks, increases fire frequency, and degrades endangered species habitat (e.g., willow fly catcher).

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

Environmental Impact Score: A, C, D

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

Environmental Impact Score: 3

-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 Arundo donaxRating (Score) High (13)

Low = 5-8 points

Medium = 9-12 points

High = 13-15 points

6) Post Entry Distribution and Survey Information: Arundo donax is widespread in CA. It receives a High (-3) 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.

The final score is the consequences of introduction score minus the post entry distribution and survey information score: Medium (10)

Uncertainty:

As this plant is well established as an invasive species in CA, there is little uncertainty associated with this assessement.

Conclusion and Rating Justification:

Based on the score listed above the pest is a high risk. This would justify an “A” rating if the species were not widely established in California. As the plant is found in over 50% of California counties, the pest would best be assigned a “B” or “C” rating. Many millions of dollars have been spent (by the state and other entities) to control Arundo donax in California. Many millions more will be spent in the near future. A “B” rating recognizes the large range of Arundo donax in California, but acknowledges the value of excluding it from new areas and preventing reinfestation of eradicated infestations.


References:      

Bell, G. P. 1997. Ecology and management of Arundo donax, and approaches to riparian habitat restoration in Southern California. In Plant Invasion: Studies from North America and Europe. J.H. Brock, M. Wade, P. Pysek and D. Green, eds. Leiden, the Netherlands: Backhuys, pp. 104-114.

Boose, A.B. and J.S. Holt. 1999. Environmental effects on asexual reproduction in Arundo donax. Weed Research 39:117-127.

Consortium of California Herbaria. Accessed 6/12/2014: ucjeps.berkeley.edu/consortium/

Goolsby, J. A., D. Spencer, and L. Whitehand. 2009. Pre-release assessment of impact on Arundo donax by the candidate biological control agents Tetramesa romana (Hymenoptera: Eurytomidae) and Rhizaspidiotus donacis (Hemiptera: Diaspididae) under quarantine conditions. Southwestern Entomologist 34:359-376.

Newhouser, M., C. Cornwall and R. Dale. 1999. Arundo: A Landowner Handbook. Accessed 6/12/2014: http://teamarundo.org/education/landowner_handbook.pdf

Perdue, R.E. 1958. Arundo donax: source of musical reeds and industrial cellulose. Economic Botany 12:368-404.

Racelis, A.E., Goolsby, J., Moran, P.J. 2009. Seasonality and movement of adventive populations of the arundo wasp (Hymenoptera: Eurytomidae), a biological control agent of giant reed in the Lower Rio Grande Basin in south Texas. Southwestern Entomologist. 34(4):347-357.

USDA Arundo donax. Accessed 6/12/2014: http://plants.usda.gov/core/profile?symbol=ardo4

Weber, E. 2003. Invasive Plant Species of the World: A Reference Guide to Environmental Weeds. CABI Publishing, U.K. 4. Dudley, T., Department of Integrative Biology, University of California, Berkeley, USA and IUCN/SSC Invasive Species Specialist Group (ISSG). 2006. Arundo donax. Accessed 6/12/2014: http://www.issg.org/database/species/ecology.asp?si=112&fr=1&sts=sss&lang=EN

Wijte, A.H. B. M., T. Mizutani, E.R. Motamed, M.L. Merryfield, D.E. Miller and D.E. Alexander. 2005. Temperature and endogenous factors cause seasonal patterns in rooting by stem fragments of the invasive giant reed, Arundo donax (Poaceae). Int. J. Plant Sci. 166(3):507-517.


Responsible Party:

Dean G. Kelch, Primary Botanist; California Department of Food and Agriculture; 1220 N Street, Sacramento, CA 95814; Tel. (916) 403-6650;

dean.kelch[@]cdfa.ca.gov


Comment Period: 11/6/17 – 12/21/17 (CLOSED)


Pest Rating: B  | Proposed Seed Rating: R


Posted by dk

Balloon Plant | Asclepias physocarpa

California  Pest Rating
Balloon Plant | Asclepias physocarpa
Family:  Apocynaceae
Pest Rating: C | Proposed Seed Rating: None

 


PEST RATING PROFILE
Initiating Event:

Asclepias physocarpa is currently Q-rated and was recently intercepted at the Benton Border Station (PDR BE0P06666758). A pest rating proposal is required to support an official pest rating.

History & Status:

Background: Asclepias physocarpa, commonly called balloon plant, is native to southeast Africa. It is an upright, shrubby perennial that typically grows 4-6′ tall and has lanceolate green leaves. This milkweed family member is perhaps best noted for its soft, spherical (balloon-like), lime-green seed pods, which are 5-7.5 cm long and covered with soft spines 7-10 mm long7. Pods change in color to tan before splitting open in the fall to release large numbers of small, black seeds, which measure approximately 4.5 mm long by 2 mm wide and are topped with a tuft of silky-white hairs approximately 3 cm long. These seeds are wind-dispersed1, 3.

Asclepias physocarpa is a food plant for the larvae of the monarch butterflies (Danaus spp.). The caterpillars are immune to the poisonous alkaloids in Asclepias physocarpa and have developed the ability to store them and pass them on to the pupa and adult butterfly, that are then unpalatable and/or poisonous to predators5.

Asclepias physocarpa is sometimes placed in the segregate genus Gomphocarpus, but recent evidence support retaining it in the large genus Asclepias (milkweeds) 2.

 Worldwide Distribution: Asclepias physocarpa is native to South Africa, Swaziland, and Mozambique. It was introduced to various Mediterranean countries, China, India, Mexico, Central America, tropical South America, and Western Australia1.

Official Control: Asclepias physocarpa is not considered to be a noxious weed by any state government authorities6. However, it is listed as an invasive weed in Hawaii, French Polynesia, the Canary Islands, New Caledonia, China, Australia, Cuba, Jamaica, India, and Italy1.

California Interceptions: One recent interception record (PDR BE0P06666758) was reported in the Pest and Damage Record Database by CDFA4. A few voucher specimens have been collected from gardens and in disturbed areas near new developments in southern CA.

The risk Asclepias physocarpa (Balloon Plant) would pose to California is evaluated below.

Consequences of Introduction:

1) Climate/Host Interaction: Asclepias physocarpa can grow in waste places, disturbed sites, and roadsides. It may able to establish in a larger but limited part of California. Therefore, it receivesMedium (2) in this category.

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: Asclepias physocarpa does not require any one host, but grows wherever ecological conditions are favorable. It receives a High (3) in this category.

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: Asclepias physocarpa spreads by seeds and each seed has a tuft of silky hairs that facilitates dispersal by wind and water. They may also be dispersed as a contaminant of crops, fodder, soil, or in mud attached to animals or machinery1. Each plant produces several hundred seeds per year. It receives a Medium (2) in this category.

Evaluate the host range 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: Asclepias physocarpa has been cultivated in California for decades, but apparently has rarely escaped gardens. It exudes a milky white latex that is poisonous to livestock and humans, so an infestation could reduce the productivity of pastures1. It receives a High (3) in this category.

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

Economic Impact:  D, F

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.

Economic Impact Score: 2

– 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: Asclepias physocarpa has so far not invaded wildland in California. It could be expected to invade flood plains or other disturbed areas. In wet, tropical areas, such as Hawaii, it can form dense thickets in pastures. It is unlikely to do this in the drier climate of California. As a garden weed, it could trigger additional private treatment programs. It receives a Medium (2) in this category.

Environmental Impact: D

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.

Environmental Impact: Score: 2

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 Asclepias physocarpa (Balloon Plant): Medium (12)  

-Low = 5-8 points

Medium = 9-12 points

High = 13-15 points

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

6) Post Entry Distribution and Survey Information: No official records indicating this species is established in the environment of California have been found, so it receives a Not Established (0) 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 (12)

Uncertainty:

This plant is not known to be established in California. No official survey has been conducted to confirm its presence. However, it has been growing in the environment of California as a common garden plant and has never been noticed as invasive weed.

Conclusion and Rating Justification:

Conclusions of the harm associated with this pest to California using all of the evidence presented above: Proposed Rating: Based on the score listed above, Asclepias physocarpa is medium risk. However, its low frequency in California after years of cultivation suggest that it will not become invasive, so a “C” rating is justified.


References:

Crop protection Compendium (Cabi). Accessed August 24, 2017: http://www.cabi.org/isc/datasheet/114618

Fishbein M., Chuba D., Ellison C., Mason-Gamer R. J., Lynch S. P. 2011. Phylogenetic relationships of Asclepias (Apocynaceae) inferred from non-coding chloroplast DNA sequences. Systematic Botany 36: 1008–1023. Missouri Botanical Garden online. Accessed August 24, 2017:  http://www.missouribotanicalgarden.org/PlantFinder/PlantFinderDetails.aspx?kempercode=e373

Pest and Damage Record Database, California Department of Food and Agriculture, Plant Health and Pest Prevention Services. Accessed   August 24, 2017: http://phpps.cdfa.ca.gov/user/frmLogon2.asp

South Africa National Biodiversity Institute, Plantzafrica, online. Accessed August 24, 2017: http://pza.sanbi.org/gomphocarpus-physocarpus

USDA Phytosanitary Certificate Issuance & Tracking System (PCIT) Phytosanitary Export Database (PExD). Accessed August 24, 2017.
https://pcit.aphis.usda.gov/pcit/

Weeds of Australia, Biosecurity Queensland, online. Accessed August 24, 2017.       https://keyserver.lucidcentral.org/weeds/data/media/Html/gomphocarpus_physocarpus.htm


Responsible Party:

Javaid Iqbal, California Department of Food and Agriculture; 1220 N Street, Sacramento, CA 95814; Tel. (916) 403-6695; plant.health[@]cdfa.ca.gov.


Comment Period:* CLOSED

11/3/17 – 12/18/17


*NOTE:

You must be registered and logged in to post a comment.  If you have registered and have not received the registration confirmation, please contact us at plant.health[@]cdfa.ca.gov.

 


Photo of Ballon plant (Asclepias physocarpa), photographed in Tonga. Photo By: Tauʻolunga, via Wikimedia Commons

Pest Rating: C | Proposed Seed Rating: None


Posted by ls