Category Archives: Weeds

Plants (weeds)

Tree of Heaven | Ailanthus altissima (Miller)

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

Comment Period: 1/17/18 – 3/3/18


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:*

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.


Posted by ls

Giant Ragweed | Ambrosia trifida L.

California Pest Rating Proposal
Giant Ragweed | Ambrosia trifida L.
Family: Asteraceae
Current Pest Rating: B
Proposed Pest Rating: B

Comment Period:  1/10/18 – 2/24/18


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:*

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.


Posted by ls

Tropical Whiteweed | Ageratum conyzoides L.

California Pest Rating Proposal
Tropical whiteweed | Ageratum conyzoides L.
Family:  Asteraceae
Current Pest Rating: Q
      Proposed Pest Rating: C |  Proposed Seed Rating: None
Comment Period: 1/5/18 – 2/19/18
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:*

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.

Graceful Spurge | Euphobia hypericifolia

California Pest Rating Proposal
Graceful spurge | Euphorbia hypericifolia L.
Malpighiales: Euphorbiaceae
Current Pest Rating:  Q
Proposed Pest Rating: A | Proposed Seed rating: N/A
Comment Period: 1/5/18 – 2/19/18
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:*

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:

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Manchurian Wild Rice | Zizania latifolia

California Pest Rating Proposal
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
Current Rating:  Q
Proposed Pest Rating: A | Proposed Seed Rating: P
Comment Period: 1/5/18 – 2/19/18
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:*

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.

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

Prickly Acacia | Vachellia Nilotica

California Pest Rating Proposal
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
Vachellia nilotica
Vachellia nilotica:  Prickly acacia
Solanales: Febaceae (Caesalpinioideae)
Current Pest Rating:  Q
Proposed Pest Rating: A | Proposed Seed Rating: P
Comment Period: 1/4/18 – 2/18/18
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:*

1/4/18 – 2/18/18


*NOTE:

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Jewels of Opar/Fameflower | Talinum Paniculatum

Jewels of Opar/Talinum paniculatum | Photo by Ronggy
California Pest Rating Proposal
Talinum paniculatum:  Jewels of opar / Fameflower
 Family:  Portulacaceae
Current Pest Rating: Q
Proposed Pest Rating: C | Proposed Seed Rating: None
Comment Period: 12/5/17 – 1/19/18
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:*

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;

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Turkey Berry | Solanum torvum

California Pest Rating Proposal
Solanum torvum:  Turkey Berry
Solanales: Solanaceae
Current Pest Rating:  Q
Proposed Pest Rating: C |  Proposed Seed Rating: N/A
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:*

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.

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

Balloon Plant | Asclepias physocarpa

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


Alligatorweed | Alternanthera philoxeroides

California Pest Rating
Alligatorweed | Alternanthera philoxeroides
Family:  Amaranthaceae
Former Pest Rating: A
CURRENT Pest Rating: A | Proposed Seed Rating: R
Initiating Event:

There was a recent find of alligatorweed in Solano County; this is the first detection in northern California in many years.

History & Status:

Background: Alligatorweed is a perennial herb with horizontal to ascending stems to 1 m long, rooting at the nodes. The flowers are small and borne in small heads with white floral bracts. Like many aquatic emergent, it has distinctive submerged and emersed forms. The submerged form has hollow, floating, emergent and submerged stems. Terrestrial plants have solid stems. Typically, plants grow rooted in soil in shallow water and form dense, interwoven floating mats that extend over the surface of deeper water. Mats can become quite dense and nearly impenetrable. The floating mats can break away and follow currents to colonize new sites. Mats disrupt the natural ecology of a site by reducing light penetration and crowding out native species. Serious infestations can create anoxic, disease-promoting, and mosquito-breeding conditions.

Worldwide Distribution: This weed is found in wet, disturbed areas. It is also a weed of rice and sugar cane fields in tropical and subtropical regions. Native to southern Asia, alligatorweed is now found in tropical and subtropical regions around the world. It is considered an invasive species in Australia, China, New Zealand, and Thailand. Alligatorweed has been introduced throughout the southeastern United States from Virginia to Texas.

Official Control: Alligatorweed has had a CDFA rating of A as a pest in California for decades. The population in Los Angeles County has been managed intermittently over the years by the county, but it still persists.  It has official status as a weed in Alabama, Arizona, Arkansas, California, Florida, South Carolina, and Texas.

California Distribution:  Alligatorweed occurs in several southern California counties. It also has been detected in Contra Costa and Kings Counties, where it is eradicated. There was a recent find of 2 colonies in southern Solano County.

California Interceptions: Alligatorweed has been sent to CDFA by land managers.

The risk Alternanthera philoxeroides (alligatorweed) poses to California is evaluated below.

Consequences of Introduction:

1) Climate/Host Interaction: Risk is Medium (2), as the plant occurs in wetlands such as the Delta and creeks and rivers, as well as irrigation canals and watering ponds. These habitats are limited but widely distributed in California.

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: Most plants do not require any one host, but grow 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: Risk is Medium (2). Alligatorweed can spread rapidly via water movement and on boats and equipment as stem fragments. It is also grown as an aquarium plant and occasionally discarded into waterways. Seeds evidently are not produced in the United States.

Evaluate the natural and artificial dispersal potential of the pest.

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

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

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

4) Economic Impact: Risk is High (3), as the plant can lower crop yields in rice fields, trigger state or international quarantines, and force changes in cultural practices by blocking canals. It has spread widely in the southeast, and has proven difficult to eradicate both there and in California. Its mats can improve habitat for mosquito larvae, leading to larger mosquito populations.

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

Economic Impact: A, C, D, E, 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: Risk is High (3) as alligatorweed could further invade the water systems of California, disrupt natural wetland communities and potentially lower biodiversity by invading wetlands. The dense growth impedes water movement, blocks the growth of native plants, and reduces available habitat for water birds and fish. Its invasion in the Delta and its tributaries could degrade habitat of rare species such as Mason’s lilaeopsis (Lilaeopsis masonii), Sacramento River Chinook salmon (Oncorhynchus tshawytscha),  and Giant garter snake (Thamnophis gigas).  Its presence would trigger additional control measures.

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

Environmental Impact: 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 Alternanthera philoxeroides (alligatorweed) : High (13)

-Low = 5-8 points

-Medium = 9-12 points

High = 13-15 points

6) Post Entry Distribution and Survey Information: Alligatorweed currently is known from 3-4 populations in northern and southern California. It receives a Medium (-2) 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:

Score: -2

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

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

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

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

Final Score:

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

Uncertainty:

Uncertainty is low, as alligatorweed has established in wetlands in California and other states. There is some uncertainty as to the actual distribution of this plant in California, as, like some other aquatic weeds, it is likely to be overlooked.

Conclusion and Rating Justification:

Conclusions of the harm(s) associated with this pest to California using all of the evidence presented above:

Proposed Rating: Despite its limited ability to disperse between watersheds, this is a potentially significant weed in California of both natural wetlands and irrigation canals. Because of its potential economic impacts, it deserves an A rating, as it has proven tenacious and is actively spreading.

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.

Consortium of California Herbaria. Accessed 10/3/2017:  ucjeps.berkeley.edu/consortium/

Florida Dept of Agriculture Weed of the Month: Alternanthera sessilis. Accessed 10/3/2017: http://www.freshfromflorida.com/Divisions-Offices/Plant-Industry/Plant-Industry-Publications/Weed-of-the-Month/April-2011-Alternanthera-Sessilis

Invasive Plant Atlas of the Mid-South. alligatorweed. Accessed 10/3/2017:    https://www.gri.msstate.edu/ipams/species.php?CName=Alligatorweed


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

10/17/17 – 12/1/17*


*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.


Pest Rating: A | Proposed Seed Rating: R

 

Smallflower Hawksbeard | Crepis pulchra

California Pest Rating
Crepis pulchra: Smallflower hawksbeard
Family:  Asteraceae 
Former Pest Rating: None
CURRENT Pest Rating: C | Proposed Seed Rating: R
Initiating Event:

Crepis pulchra had no previous pest rating; it has been reported in Napa, Solano and Contra Costa counties. A pest rating proposal is required to determine a permanent rating for this pest.

History & Status:

Background: Crepis pulchra is a flowering plant in the daisy family with the common name smallflower hawksbeard. Crepis pulchra is widespread in Europe, Central Asia and parts of Africa. It has become naturalized in the parts of United States and Canada1. It is annual herb up to 40 inches tall with erect, glandular stem. One plant can produce up to 40 flower heads and each flower can produce 30 yellow ray florets. The leaves are alternate, toothed and the basal leaves are pinnately lobed. Flowering occurs from April to August. It can grow up to 3000 m elevation in dry open habitats, rolling grasslands, pastures, abandoned fields, waste areas, railroads and roadsides1.

Worldwide Distribution: Crepis pulchra is widespread across much of Europe, Morocco, Algeria, western and central Asia. It has been  reported in Ontario Canada  and TX, OK, MO, AR, LA, MS, AL, FL, GA, SC, NC,VA, DE, WV, OH, IL, KY, TN & OR in the United States3,1.

Official Control: Crepis pulchra is not declared or considered noxious by any state government authorities7.

California Distribution:  Crepis pulchra currently is known in limited areas of Solano, Napa & Contra Costa counties2.

California Interceptions: There were 8 vouchers submitted from Solano, Napa & Contra Costa counties between 1999 and 20112.

The risk Crepis pulchra (Smallflower hawksbeard) would pose to California is evaluated below.

Consequences of Introduction:

1) Climate/Host Interaction: The plant has adapted to a wide area in the eastern states and Oregon. California has similar ecologically conditions as its native range, so it may be established on a larger but limited part of California. Therefore Crepis pulchra receives a Medium (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: Most plants do not require any one host, but grow 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: Crepis pulchra reproduces only by seed; each plant can produce 40 seeded fruits5. These fruits are dispersed short distances by foraging animals, human activity or by wind. They may be dispersed longer distances by vehicles, on larger animals 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: Crepis pulchra is a weed in some agricultural situations and it may reduce crop yield where it establishes. It receives a Low (1) in this category.

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

Economic Impact: A

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: Crepis pulchra has not yet spread widely in California. If it does spread, it might 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 Crepis pulchra (Smallflower hawksbeard): Medium (10)

Low = 5-8 points

Medium = 9-12 points

High = 13-15 points

6) Post Entry Distribution and Survey Information: Crepis pulchra has been reported in Napa, Solano & Contra Costa counties and seems likely to be restricted to this area at this time. 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:

Score: -1

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

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

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

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

Final Score:

The final score is the consequences of introduction score minus the post entry distribution and survey information score: Medium (9)

Uncertainty:  

Crepis pulchra has been present in California about 30 year ago and it is localized in a limited area. Due to its relatively noninvasive nature, there are limited chances that it will spread widely in California.

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 medium risk. A “Crating is recommended, because of lake of evidence of its invasiveness.

References:
  1. Flora of North America online.  Accessed March 9, 2017 http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=242416376
  2. Jepson Herbarium. Online UC Berkeley.  Accessed March 9, 2017  http://ucjeps.berkeley.edu/cgi-bin/get_consort.pl?taxon_name=Crepis%20pulchra
  3. Plant profiles  USDA    Accessed March 9, 2017 https://plants.usda.gov/core/profile?symbol=CRPU3
  4. Pest and Damage Record Database, California Department of Food and Agriculture, Plant Health and Pest Prevention Services. http://phpps.cdfa.ca.gov/user/frmLogon2.asp
  5. Wildflower of the southeastern US.   Accessed March 9, 2017  http://2bnthewild.com/plants/H270.htm
  6. S. National Plant Germplasm System Accessed March 9, 2017 https://npgsweb.ars-grin.gov/gringlobal/taxonomydetail.aspx?id=310895
  7. USDA Phytosanitary Certificate Issuance & Tracking System (PCIT) Phytosanitary Export Database (PExD). Accessed January 03, 2017 https://pcit.aphis.usda.gov/pcit/

 


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

9/12/17 – 10/27/17*


*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.


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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Jeweled distaff thistle | Carthamus oxyacantha

Jewel distaff thistle (photo by Steve Hurst, hosted by the USDA-NRCS PLANTS Database)
Jewel distaff thistle (photo by Steve Hurst, hosted by the USDA-NRCS PLANTS Database)
California Pest Rating
Carthamus oxyacantha:  Jeweled distaff thistle
Family:  Asteraceae
Former Pest Rating: None
CURRENT Pest Rating: B | Proposed Seed Rating: P
Initiating Event:

Jeweled distaff thistle was reported in California in the late 1970’s and had no previous pest rating. A pest rating proposal is required to determine a permanent rating for this pest.

History & Status:

Background: Jeweled distaff thistle is a spiny-leaved annual weed that can grow up to 1.5 m tall. Like other spiny plants in the genus Carthamus, this species is not eaten by livestock, enabling it to spread on grazing lands2. The yellow flowers are born in flower heads approximately two to three cm in diameter and the leaves are covered with spines. It is a wild safflower relative found in arid and semi-arid environments in central and southern Asia5. It was collected in 1978 in Monterey County, California. It is considered by the United States Department of Food and Agriculture to be a noxious weed subject to eradication if found. Jeweled distaff thistle is a pernicious weed of agricultural lands especially, it reduces the yield of cereal crops. Jeweled distaff thistle most closely resembles cultivated safflower; it has smaller heads and much spinier leaves1.

Worldwide Distribution: Jeweled distaff thistle is reported from Afghanistan, India, Iran, Iraq, Saudi Arabia, Syria, Kyrgyzstan, Uzbekistan, Pakistan, Azerbaijan, Armenia, Tajikistan and Turkmenistan4.

California Distribution:  It was reported only in Monterey County, where it may be eradicated.

Official Control: Jeweled distaff thistle is listed as a harmful organism in

Colombia, Honduras and Mexico6. It is listed by U.S. Federal government as Noxious weed in Florida, Minnesota South Carolina, Massachusetts and Class

“A” Noxious weed for Alabama, North Carolina and Vermont7.

California Interceptions: Historically, only two vouchers were submitted in 1978 from Monterey County3.

The risk Carthamus oxyacantha (Jeweled distaff thistle) would pose to California is evaluated below.

Consequences of Introduction:

1) Climate/Host Interaction: Jeweled distaff thistle is adapted to central and southern Asia and similar climates. It may able to establish in a larger but limited part of California like Carthamus tinctorius. It receives a Medium (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: Jeweled distaff thistle do not require any one host, but grow 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: Jeweled distaff thistle reproduces only by seed; each plant can produce up to 36 flower head that produces 15 to 20 single-seeded fruits5. These flower heads are dispersed short distances by foraging animals, human activity or by wind. They may be dispersed longer distances by vehicles, on larger animals 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: Jeweled distaff thistle could invade crops, especially summer season crops in California. It could decrease crop yield and can lower the crop value, as it has been reported in its native range. Where adapted it displaces both native plants and other plants; this could negatively change normal cultural practices. It had spiny-tipped leaves with phyllaries heads which could injured the agriculturally important animals.  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, 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: Jeweled distaff thistle has not yet spread widely in California. If it does spread, it might 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 Carthamus oxyacantha (Jeweled distaff thistle): Medium (12)

Low = 5-8 points

Medium = 9-12 points

High = 13-15 points

6) Post Entry Distribution and Survey Information: Jeweled distaff thistle has been reported only in Monterey County and seems likely eradicated in this area. It receives a Low (-1) in this category.

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

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

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

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

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

Final Score:

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

 Uncertainty:

Jeweled distaff thistle has been known in California for decades, although it has not yet spread widely, there is nothing to stop it spreading in the appropriate habitats. There is some uncertainty as to how well it can spread in California if it escapes.

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 medium risk weed with a distribution in Monterey County. A B” rating is recommended, as the plant is invasive and is a federal noxious weed.

References:
  1. Flora of North America  online   Accessed April 26, 2017. http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=200023631
  2. Federal Noxious Weed Dissminules of U.S. Accessed May 9, 2017.    http://keys.lucidcentral.org/keys/FNW/FNW%20seeds/html/fact%20sheets/Carthamus%20oxyacantha.htm
  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 May 9, 2017.
    http://ucjeps.berkeley.edu/cgi-bin/get_consort.pl?taxon_name=Carthamus+oxyacantha&county=06053
  4. US National Plant Germplasm system. Accessed May 9, 2017. https://npgsweb.ars-grin.gov/gringlobal/taxonomydetail.aspx?9239
  5. Sullaiman Mohammed, Mohammad A Fredan 2015, American Journal of Environmental Sciences. Accessed May 9, 2017.
    http://thescipub.com/PDF/ajessp.2015.125.132.pdf
  6. USDA Phytosanitary Certificate Issuance & Tracking System (PCIT) Phytosanitary Export Database (PExD). Accessed May 9, 2017
    https://pcit.aphis.usda.gov/pcit/
  7. USDA  Natural Resouces Conservation Services online. Accessed May 9, 2017
    https://plants.usda.gov/core/profile?symbol=CAOX6

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

45-day comment period: 7/20/17 – 9/3/17


NOTE:

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Pest Rating: B | Proposed Seed Rating: P