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Coco-Yam, Elephant Ear or Taro | Colocasia esculenta

California Pest Rating for
 Colocasia esculenta : Coco-Yam, Elephant Ear or Taro  
Family: Araceae
Pest Rating: D  |   Proposed Seed Rating: N/A
PEST RATING PROFILE
Initiating Event:

This plant has been rated as “Q” on the CDFA Plant Pest Rating since 2015.

History & Status:

Background: Colocasia esculenta is a tropical plant grown primarily for its edible corms. It is cultivated as a vegetable most commonly known as taro,Gabi and Abi or Avi. There are dozens of other common names used in other parts of the world including culcas from which the genus name Colocasia is derived; the descriptive anatomical name, elephant ear, eddo, imo, dasheen, coco-yam and malombo. It is believed to be one of the earliest cultivated plants2.

Plants have been in cultivation for over 2,800 years as a food crop in equatorial regions including India, China, Southeast Asia, Indonesia, Polynesia, the Mediterranean, Africa, and South America. All parts of the plant are edible if they are thoroughly steamed or boiled to first remove calcium oxalate crystals.The cooked leaves are used in Hawaiian luaus and the corms are mashed into poi1.

It was grown in Africa and was first brought to the Americas as a food crop for slaves. In 1910, Colocasia esculenta was promoted as an alternative crop to potatoes by the USDA5. There are more than 200 cultivars of taro, selected for their edible corms or cormels, or their tropical looking ornamental foliage2. It is cultivated commercially on a small scale in the Central valley and Sacramento valley of California6.

Official Control:    None at this time in California.

California Distribution: Colocasia esculenta is a perennial herb that is not native to California. It has been reported in the Delta in Sacramento, San Joaquin and Solano Counties. It also been found in Southern CA in Orange County3.

California Interceptions: Colocasia esculenta is occasionally sold in nurseries in CA. It is consumed as a vegetable in California and sold state-wide in produce markets.

United States: Colocasia esculenta is wide spread in the southeastern United States4. It is a most important source of food in the Hawaiian Islands.

Coco-Yam-US-Map

Worldwide Distribution: Colocasia esculenta is an ancient crop grown throughout the tropic and sub-tropics. Because Colocasia esculenta has been in cultivation for so long, no one knows  where it truly is native, but all evidence points to Southeast Asia. It is viewed as invasive in FL, HW, PR, Queensland, Cuba, Costa Rica and many of the Pacific Islands.

Consequences of Introduction: 

1) Climate/Host Interaction: Risk is Medium (2), as Colocasia esculenta is naturalized in the marshy and watershed areas throughout southeastern America and is spreading there. It is established in one area of the Delta in California.

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

Score: 2

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

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

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

2) Pest 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:

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) as the plant  spreads vegetatively through rhizomes, stolons, offshoot corms or vegetative fragments.It does not seem to produce seed in CA.

Evaluate the dispersal potential of the pest:

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

Medium (2) has either high reproductive or dispersal potential

High (3) has both high reproduction and dispersal potential

4) Economic Impact: Risk is Medium (2) as Colocasia produces 2.5′ wide by 3.5′ long leaves with up to 30″ tall patch that could lower the crop yield due to shading and changes in the cultural practices where it is established.

Evaluate the economic impact of the pest to California using these criteria:

Economic Impact:  A, D

A. The pest could lower crop yield

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

C. The pest could trigger the loss of markets (includes quarantines by other states or countries)

D. The pest could negatively change normal production cultural practices

Economic Impact Score: 2

Low (1) causes 0 or 1 of these impacts

Medium (2) causes 2 of these impacts

High (3) causes 3 or more of these impacts

5) Environmental Impact: Risk is High (3) as it invades wetland edges, swamps, blackwater streams, lakes and disrupt natural wetland communities of California. It is established in a state park where it forms a dense thicket at the wetland interface; this will encourage treatment for control. If it spreads, it could affect populations of sensitive species such as Mason’s lilaeopsis (Lilaeopsis masonii), CA Clapper rail (Rallus obsoletus), Suisun aster (Symphyotrichum lentum) and Delta tula pea (Lathyrus jepsonii).

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

Economic 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. Significantly impacting cultural practices, home/urban gardening or ornamental plantings.

Score the pest for Environmental Impact:

Low (1) causes none of the above to occur

Medium (2) causes one of the above to occur

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

Consequences of Introduction to California for Colocasia esculenta :

Rating (Score): Add up the total score and include it here:

Low = 5-8 points

Medium = 9-12 points

High = 13-15 points

Total points based on above criteria, which does not take into account the pathogen’s already wide distribution in California: Medium (12).

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: Low (–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: (11)

Uncertainty:

This plant has been known in Southeastern America for over 100 years and spreading colonies have been detected.So, there is low uncertainty that it will continue to spread in wetlands of California.

Conclusion and Rating Justification:

Proposed Rating: based on the score listed above, the pest is Medium risk for further invasions of California. It has a potential  to invade the wet areas of California, and it is already reported in 4 counties. Nevertheless, as Colocasia esculenta is an agricultural commodity in California, a “D” rating is justified.

References:

1.    Avent Tony and Carey Dennis, (2016). Cool Colocasias; Plant Delights Nursery, Inc. Accessed  11-15-2016.

http://www.plantdelights.com/Article/Colocasia-Elephant-Ears

  1. Colocasia esculenta, Encyclopedia of Life.Eol community website .

http://www.eol.org/pages/1091931/overview

  1. Calflora: Information on California plants for education, research and conservation, with data contributed by public and private institutions and individuals, including the Consortium of California Herbaria.  2016. Berkeley, California. Accessed 11-15-2016.

http://www.calflora.org/cgi-bin/species_query.cgi?where-calrecnum=13042

  1. Federal database with information on identification and distribution, and links to websites in individual states. Accessed 11-15-2016.

http://plants.usda.gov/core/profile?symbol=COES

  1. Swearingen, J., C. Bargeron. 2016 Invasive Plant Atlas of the United States. University of Georgia Center for Invasive Species and Ecosystem Health

http://www.invasiveplantatlas.org/subject.html?sub=5369

  1. Taro root (colocasia esculenta) reported Naturalizing in ca;ifornia by CA State Parks.

http://www.cal-ipc.org/symposia/archive/pdf/2014/Poster2014_Robison.pdf

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 Format:

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

Example Comment: 

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

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

♦  Comments may not be posted if they:

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

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

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

Violates agency regulations prohibiting workplace violence, including threats.

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

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

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

Posted by ls

Weeds

Arctotheca calendula (L.) Levyns (Capeweed)

California Plant Pest Rating
Arctotheca calendula (L.) Levyns (Capeweed)
Asterales; Asteraceae
Pest Rating: A  |    Proposed Seed Rating: P
PEST RATING PROFILE
Initiating Event:

This plant was  listed as a noxious weed in California in 2010 (Invasive species compendium- CABI).

History & Status:

Capeweed is a Rosette-forming winter annual, up to 30 cm tall. It has typical daisy flowers heads with dark purple disk flowers and yellow ray flowers. Plants typically colonize open sites with exposed soils. Capeweed is introduced from South Africa, but it is also common in Australia, where it is an abundant pasture weed. Certain capeweed populations in Australia have developed resistance to bipyridylium herbicides. Handling plants can cause contact dermatitis in sensitive individuals. Capeweed has proven invasive in horse pastures and vineyards where taller, more palatable vegetation is removed. There has been much confusion between capeweed and prostrate capeweed (A. prostrata). Prostrate capeweed is a common groundcover perennial sold in flats in nurseries in mild areas of California. Prostrate capeweed can be locally invasive where it has been planted, as it actively spreads to form patches vegetatively. However, it does not form seeds in California; perhaps there is only one self-incompatible clone in cultivation at this time.

Official Control: Capeweed has been recognized as a harmful organism in Brazil, Colombia and Peru. It has naturalized in Australia, New Zealand and other countries in Asia, Africa, South America and Europe.        

California Distribution: Capeweed may have arrived in California in a shipment of grass seed from Australia, where it is a common weed.  Because of taxonomic confusion with prostrate capeweed, the range of capeweed is somewhat ambiguous. It has been reported in Alameda*, Amador, Humboldt*, Los Angeles, Mendocino, Monterey*, Marin*, Merced*, Sacramento, Santa Barbara, Santa Cruz*, San Francisco, San Luis Obispo, San Mateo*, Sonoma, Stanislaus* and Yolo Counties (Cal Flora Databse: Distribution by county: Arctotheca calendula  (L.) Levyns Cape weed). Asterixed county reports are supported by confirmed, identified vouchers.

California Interceptions: 11 vouchers have been submitted to CDFA for identification between 2000 and 2015 (Pest and Damage Report Database).

International: Capeweed  is native to South Africa. It is reported as naturalized in central Portugal and southwestern Spain, southern Portugal, New Zealand and as an environmental weed in Australia. (Lazarides and Hince, 1993 ). Capeweed has been raised as an ornamental in England since the mid-18th century (USDA APHIS Pest Risk Assessment).

Habitat: Capeweed prefers sandy, well drained soil, sand dunes,steam banks and rocky outcrops. It is used as a groundcover (Joffe, 2001). It does not thrive on soils low in potassium and high in salt. Areas on light textured soils devoid of vegetation during late summer /autumn are most likely to become infested with capeweed (Department of Primary Industries, Water and Environment , Tasmania, 2002). As it is avoided by livestock, it can spread quickly in horse pastures.

This risk capeweed would pose to California is evaluated below:

Consequences of Introduction:

1) Climate/Host Interaction: Risk is High (3), as this plant is naturalized along the coast of California and at five inland sites in the San Joaquin/Sacramento region. (Cal Flora Databse: Distribution by county: Arctotheca calendula (L.) Levyns: Cape weed).

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

Score: 3

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) Pest 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: 3

– 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). Capeweed has both high reproduction potential and highly mobile propagules. The plant reproduces via seeds. One plant can spawn a population spreading to cover up to 200 square feet in one to two years (Mathias, 1982; CDFA , 2002). Capeweed stem pieces with nodes can spread to new location by heavy equipment (Bossard, et al. 2002). Dispersal can be aided by wind or in contaminated soil. (Miles, 2002) Human activity and animals also aid in spread of seeds and rooted stolons (Wood 1994).

Evaluate the dispersal potential of the pest:

Score: 3

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

Medium (2) has either high reproductive or dispersal potential

High (3) has both high reproduction and dispersal potential

4) Economic Impact: Risk is High (3) as capeweed can become a troublesome weed in pastures, crops and home gardens in California. It can smother grasses and clover seedlings in newly sown pastures in the state. Capeweed can dominate overgrazed pastures in drier regions of California and can die off during summer, leaving bare areas vulnerable to invasion by other weeds.

It invades disturbed soil along roadsides and in crops. Capeweed can cause poisoning in livestock, if they consume it. Seeds can become embedded in wool. This can result in reduced yields. It reduces the value of stock by lowering their weight. Capeweed does not provide continous ground cover and feed value over summers  (APHIS Weed Risk Assesment).

Evaluate the economic impact of the pest to California using these criteria:

Economic Impact: A, 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 by other states or countries)

D. The pest could negatively change normal production 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 use

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) in California. Capeweed disrupts natural grassland communities that are grazed, invades native habitat along the coast including coastal prairie, and triggers additional treatment to control it. In desert areas of California, Capeweed can increase the risk of soil erosion as its mature plants dry up and break quickly, leaving no cover over summer. It can also threaten native plant communities in Califorinia by crowding out grasses, herbs and small herbs (Bossard et al., 2000). Capeweed can cause hay fever and handling plants can cause contact dermatitis in sensitive people (CDFA 2002). It can escape into lawns and adjacent planting areas in California (Perry, 1992). Since there are no registered biological agents for Capeweed control, additional private or official treatments may be needed for its control ( CDFA 2002).

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

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. Significantly impacting cultural practices, home/urban gardening or ornamental plantings.

Score the pest for Environmental Impact:

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 capeweed:

Add up the total score and include it here:

Low = 5-8 points

Medium = 9-12 points

High = 13-15 points

Total points based on above criteria: High (15).

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: Medium (–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: (13).

Uncertainty:

Capeweed has naturalized in coastal and some inland areas of Northern California. There is confusion as to whether reports refer to capeweed or prostrate capeweed. Nevertheless, it has the potential to get widely established in desert areas and  grazed pastures. There is little uncertainty as to whether this plant can establish widely in CA, as it has establsihed in CA and has spread widely in silmilar habitats in Australia.

Conclusion and Rating Justification:

Proposed Rating: based on the score listed above the pest is a high risk. Because it has spread in certain areas of northern california and has a good potential to widely spread in the state, an A rating would be justifed. Because it can spread in grass seed, it should be prohibited from seed for planting.

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.

Bossard, C.C., J.M. Randall, and M.C. Hoshovsky. 2000. Invasive Plants of California Wildlands. pp.49-53. University of California Press.

California Department of Food and Agriculture (CDFA) Encycloweedia Homepage. 2002. Notes on Identification, Biology, and Management of Plants defined as Noxious Weeds by California Law. http://pi.cdfa.ca.gov/weedinfo/.

Cal Flora Databse: Distribution by county: Arctotheca calendula  (L.) Levyns

Capeweed https://www.calflora.org/cgi-bin/county_taxon.cgi?where-calrecnum=634

Consortium of California Herbaria (ucjeps.berkeley.edu/consortium/). 2014.

Department of Primary Industries, Water and Environment, Tasmania website:

www.dpiwe.tas.gov.au. Weed Service Sheet 128 – Arctotheca calendula. 2002.

Environmental weeds of Australia for Biosecurity Queensland : Arctotheca Calendula– Factsheet http://keyserver.lucidcentral.org/weeds/data/media/Html/arctotheca_calendula.htm

Fairnie, I.J. Nitrite poisoning in sheep due to capeweed (Arctotheca calandula). Australian Veterinary Journal 1969, February; 45(2): 78-9.

Invasive species compendium: Arctotheca calendula (Capeweed): Accessed 11/9/2016 http://www.cabi.org/isc/datasheet/6729#20097200136

Lazarides, M. and B. Hince, editors. 1993. CSIRO handbook of economic plants of Australia. P. 24. CSIRO, Victoria, Australia

Lehtonen, Polly, USDA-APHIS PPQ Biological and Technical Services: Weed Risk Assesment  for Arctotheca calendula (L.) Levyns; Accessed 11/9/2016 https://www.aphis.usda.gov/plant_health/plant_pest_info/weeds/downloads/wra/ArctothecacalendulaWRA.pdf

Mahoney, A. M. & R. J. McKenzie. 2008. Notes On Two Southern African Arctotis Species (Arctotideae: Asteraceae) Growing In California. Madroño 55: 244–247.

Mathias, M. E., editor. 1982. Flowering Plants in the Landscape. University of California Press. p. 139

Miles, J. 2002. Capeweed (Arctotheca calendula) weed fact sheet, Eurobodalla Shire Council, New South Wales, Australia, South Coast Weeds website. Accessed 11/9/2016 http://www.esc.nsw.gov.au

Perry, B. 1992. Landscape Plants for Western Regions, an illustrated guide to plants for water conservation. Claremont CA: Land Design Pub. pp. 94, 125-126.

Pest and Damage Record Database; Plant Health and Pest Prevention Services, California Department of Food and Agriculture. Accessed on 11/9/2016

Pethick D.W., Chapman, H.M. The effect of Arctotheca calendula (capeweed) on digestive function of sheep. Australian Veterinary Journal 1991 Nov.; 68(11): 361-3

Weed Identification in Australia: Capeweed http://www.weeds.org.au/cgi-bin/weedident.cgi?tpl=plant.tpl&state=&s=&ibra=all&card=H70

Wood, H. 1994. The introduction and spread of Capeweed, Arctotheca calendula (L.)Levyns (Asteraceae) in Australia. Plant Protection Quarterly 9, 2-8.

Responsible Party:

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

Comment Format:

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

Example Comment: 

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

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

♦  Comments may not be posted if they:

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

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

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

Violates agency regulations prohibiting workplace violence, including threats.

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

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

Pest Rating: A  |    Proposed Seed Rating: P

Posted by ls

Weeds

False Yellowhead | Dittrichia viscosa (L.) Greuter

California Pest Rating for
False Yellowhead | Dittrichia viscosa (L.) Greuter
Asteridae: Asteraceae
Pest Rating: A  |   Proposed Seed Rating: P
PEST RATING PROFILE
Initiating Event:

False yellowhead (Dittrichia viscosa) has been rated as “Q” on the CDFA Plant Pest Rating since 2014. This plant is on the “Alert list” for Environmental weeds in Australia. Recent reports of its presence in Solano County has prompted issuance of a permanent rating.

History & Status:

False yellowhead (Dittrichia viscosa) is an erect, perennial, soft-wooded shrub, 1–1.5 m tall and 1 m wide. Its leaves are greyish-green, partially clasping and elliptical. The yellow flowers are daisy-like and 10–20 mm across, with radiating petal-like flowers. The flowers are surrounded by narrow, triangular, sticky bracts. The seeds are approximately 2 mm long, with about 15–25 bristles at the base (Ratcliffe, 1976). The roots can be quite substantial, even in small plants. The young stems and leaves are covered with glandular hairs which exude a sticky foul-smelling oil. The oil can cause allergic reactions. It is native to Northern Africa, the Middle East, India, and southern Europe (Brullo & de Marco, 2000), but it  has expanded its range in response to human disturbance and proved tolerant of harsh water and mineral stress (Wacquant, 1990; Thompson, 2005; Murciego et al. 2007). False yellowhead inhabits disturbed places, roadsides, pastures, fields, riparian woodlands, levees, washes, and margins of tidal marshes. (Blanco 2011; Wacquant, 1990).  False yellowhead was first found in California in 2014 (Consortium of California Herbaria). False yellowhead’s ecology seems to be similar to its close relative stinkwort (D. graveolens), a serious weed in California (Ditomaso & Brownsey, 2013; Wacquant, 1990).

Official Control: False yellowhead has not been listed as a harmful organism (Phytosanitary export database- USDA Phytosanitary Certificate issuance and Tracking system (PExD). The Solano County Agricultural Commissioner’s staff has been controlling and monitoring this plant since it was first found.

California Distribution:  Known only from Solano County in California (Consortium of California Herbaria).

California Interceptions: It has been found growing along McGary Road in Solano County, as reported multiple times by the county agricultural commissioner’s office. (Pest and Damage Report Database). It has not yet been intercepted at CA borders.

United States: False yellowhead was collected in three states in the eastern U.S. (USDA Plants), but it is unlikely that it persisted beyond the late1800s. (FNA, 1993+).

International: False yellowhead is common throughout the Mediterranean. Its native range includes the coasts of southern Europe (including France, Spain, Greece, Italy, Bulgaria and Turkey), the Middle East (Israel, Jordan and Syria), as well as northern Africa (Algeria, Egypt and Libya) (Ratcliffe, 1976; Brullo & de Marco, 2000). It is spreading rapidly in Southeastern and Southwestern Australia (Baldwin et al., 2012).

The risk False yellowhead would pose to California is evaluated below:

Consequences of Introduction: 

1) Climate/Host Interaction: False yellowhead is a ruderal plant species adapted to areas disturbed and altered by human activity (Wacquant, 1990). The typical habitats of viscosa include arroyos, abandoned agricultural fields, roadsides, trails, and disturbed urban sites (Ratcliffe, 1976). It occurs on various soil types and is tolerant of high mineral soils (Wacquant, 1990). Although it is drought tolerant, it prefers the margins of wetlands (Warlop et al., 2010). Once established after disturbance, it can spread to less disturbed situations (Wurcquart, 1990). Therefore, false yellowhead receives a High (3) in this category.

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

 Score: 3

– 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: 3

– 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: False yellowhead spreads via seed. Seed dispersal is aided by an arrangement of bristles at the end of the seed (pappus) that catches the wind. (Australian Weed Management Guide). It produces prolific seed that secretes a sticky exudate causing seed to cling to clothing, animal fur and machinery. The seed bank of its close relative Stinkwort is moderately persistent (Cal-IPC). False yellowhead receives a High (3) in this category.

Evaluate the natural and artificial dispersal potential of the pest:

Score: 3

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

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

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

4) Economic Impact: False yellowhead can lower range productivity. It is unpalatable to livestock (Philbey and Morton, 2000). Furthermore, because of the barbs on the pappus of the seeds, it leads to enteritis and other gastrointestinal disease in livestock. As they are similar to those of Stinkwort, false yellow head is likely to have similar impacts on livestock. It is thought that false yellowhead would have similar impacts on grazing animals. Thirty years after introduction to South Australia, false yellowhead is a bad weeds of roadsides. Some people are allergic and develop severe dermatitis after contacting false yellowhead plants (Máñez et al., 1999; Hernández et al., 2001). It is also allelopathic to other plants and suppresses seed germination (Omezzine et al., 2011).  False yellowhead receives a Medium (2) 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: False yellowhead is likely to trigger new chemical treatments by ranchers and land managers. The plant can dominate roadsides, disturbed grassland, and wetland margins, excluding native plants and lowering biodiversity (Australia Weed Management Guide). Rare taxa that might be affected in CA include grassland species such as showy Indian clover (Trifolium amoenum) and CA filaree (California macrophylla), and vernal pool species such as Burke’s goldfields (Lasthenia burkei) and CA tiger salamander (Ambystoma californiense). The plant can disrupt natural communities and exclude cultural plants from a landscape. False yellowhead receives a High (3) in this category.

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.

Score the pest for Environmental Impact:

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 False yellowhead: High (14)

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: False yellowhead has been found in one county in California. 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: High (13)

Uncertainty:

Uncertainty is low, as the plant has spread widely in the Mediterranean and South Australia. It also shows signs of fast establishment in its one known occurrence in California.

Conclusion and Rating Justification:

An A rating is recommended, as the plant is invasive, but not yet widespread. There is still the chance to eradicate this plant from North America.

References:

Australian Weed Management Guide. False yellowhead. Accessed 10/11/2016:

https://www.environment.gov.au/biodiversity/invasive/weeds/publications/guidelines/alert/pubs/d-viscosa.pdf

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.

Blanco G. 2011. Dittrichia in Claves de la Flora Vascular de Andalucía Oriental. G. Blanca, B. Cabezudo, M. Cueto, C. Morales Torres & C. Salazar, eds.  Servicio de Publicaciones de las Universidades de Almería, Granada, Jaén y Málaga. Universidad de Granada. Granada, Spain.

Brullo, S & de Marco, G. 2000. Taxonomical revision of the genus Dittrichia (Asteraceae), Portugaliae Acta Biol. 19: 341–354.

Consortium of California Herbaria. Accessed 10/11/2016: ucjeps.berkeley.edu/consortium/

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

Hernández, V., R. M. del Carmen, S. Máñez, J. M. Prieto, R. M. Giner, & J. L. Ríos. 2001. A mechanistic approach to the in vivo anti-inflammatory activity of sesquiterpenoid compounds isolated from Inula viscosa. Planta Medica 67: 726-731.Máñez, S., M. C. Recio, I. Gil, C. Gómez, R. M. Giner, P. G. Waterman & J. L. Ríos 1999. A glycosyl analogue of diacylglycerol and other antiinflammatory constituents from Inula viscosa. Journal of Natural Products 62: 601-604.

Murciego, A. M., A. G. Sánchez, M. A. R. González, E. P. Gil, C. T. Gordillo, J. C. Fernández & T. B. Triguero 2007. Antimony distribution and mobility in topsoils and plants (Cytisus striatus, Cistus ladanifer and Dittrichia viscosa) from polluted Sb-mining areas in Extremadura (Spain). Environmental Pollution 145: 15-21.

Omezzine, F., A. Rinez, A. Ladhari, M. Farooq & R. Haouala. 2011. Allelopathic potential of Inula viscosa against crops and weeds. International Journal of Agriculture and Biology 13: 841-849.

Parolin P, M Ion Scotta, & C Bresch. 2014. Biología de Dittrichia viscosa, una planta ruderal del Mediterráneo. Phyton (Buenos Aires) vol.83.

Philbey A. & A.G. Morton 2000. Pyrogranulomatous enteritis in sheep due to penetrating seed head of Dittrichia graveolens. Australian Veterinary Journal 78: 858-860

Pest and Damage Record Database, Plant Health and Pest Prevention Services, CA Department of Food and Agriculture. Assessed Date: 10/18/2016

Phytosanitary Export Database- USDA Phytosanitary Certificate issuance and Tracking system (PExD), Date Assessed: 10/18/2016. https://pcit.aphis.usda.gov/PExD/faces/PExDReport.jsp

Ratcliffe, D. 1976. Dittrichia in Flora Europaea Vol. 4: Plantaginaceae to Compositae. T. G. Tutin, V. H. Heywood, N. A. Burges, D. H. Valentine, S. M. Walters, & D. A. Webb, eds. Cambridge University Press. United Kingdom.

Sinden J., R. Jones, S. Hester, D. Odom, C. Kalisch & R. James (2004). The economic impact of weeds in Australia. Report to the CRC for Australian Weed Management. Pp. 1-65.

Thompson, J. D. 2005. Plant Evolution in the Mediterranean. Oxford University Press, Oxford.

USDA Plants; Dittrichia viscosa. Accessed 10/11/2016: http://plants.usda.gov/core/profile?symbol=DIVI6

Wacquant, J. P. 1990. Biogeographical and physiological aspects of the invasion by Dittrichia (ex-Inula) viscosa W. Greuter, a ruderal species in the Mediterranean Basin. Pp. 353-364 in Biological Invasions in Europe and the Mediterranean Basin. F. di Castri, A.J. Hansen, and M. Debussche, eds. Springer Netherlands, Dordrecht.

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

Pest Rating: A  |   Proposed Seed Rating: P

Posted by ls

Weeds

Old Man’s Beard | Clematis Vitalba

California Pest Rating for
Clematis vitalba: Old man’s beard
               Ranunculales: Ranunculaceae
Pest Rating: A  |  Proposed Seed Rating: P
PEST RATING PROFILE
Initiating Event:

Old Man’s beard (Clematis vitalba) is listed as a B rated quarantine weed in Oregon and Class C noxious weed in Washington. In 2014, this species was added as new alert weed in California (Joe DiTomaso, UC Davis) and was listed on California Invasive Species Council’s watch list in December, 2015. It has been reported several times growing in Marin, Santa Cruz and San Francisco Counties recently. (Cal Flora: Distribution by County: Clematis vitalba). Due to this, a risk assessment of this known weed is critical to designate an official rating.

History & Status:

Old man’s beard is a broad leaved, deciduous, woody climbing vine that  lives up to 40 years (West, 1991). It grows to 65 feet long and acts as a ground cover in the absence of trees to climb. New shoots can grow 6 feet per year and older plants can grow 30 feet per year. (Kings county Noxious Weed Control Program). Old Man’s Beard is native to Europe, Africa and south west Asia. It has been introduced to and naturalized in North America, Australia and New Zealand. This plant is found on disturbed lands, forest edges and wooded areas with partial sun. It is also capable of growing on hedgerows, fence lines, dunes, riverbanks and grassland. Old man’s beard can easily invade riparian vegetation, waste land, tall grasses and disturbed urban areas. Since this plant grows on road sides, the seeds can be transported on vehicles from known infestations to new sites. The highest risk of introduction is through the intentional introduction of this plant as an ornamental, plants and seeds sold by nurseries, mail order and online sales (Invasive Species Compendium: CABI Database: Clematis vitalba). It is self-pollinated and can also be pollinated by wind or insects. Old man’s beard produces up to 100,000 seeds per plant per year. Seeds can remain viable for up to five years in the soil (Kings county noxious weed control program).

Official Control: Old man’s beard is recognized as a harmful organism in New Zealand and is listed as invasive weed in the United Kingdom and Canada. In the United States, it is recognized as invasive in Oregon, Washington and Maine (Invasive species compendium: CABI Database: Clematis vitalba). It is not yet fully established in California.

California Distribution: Old man’s beard has been observed in limited areas of Marin, Santa Cruz and Santa Clara counties (Consortium of California Herbaria).

California Interceptions: Old man’s beard has not been intercepted in California through regulatory pathways (Pest and Damage Report Database, CA Department of Food and Agriculture), but has been reported to CDFA from National and State Park personnel.

United States:  Old man’s beard has a long history in North American Horticulture. It was first introduced into the US between 1830 and 1840 (ACS, 2003). Currently, it has a limited naturalized distribution in the states of Oregon, Maine, Washington and California (Invasive species compendium: CABI Database: Clematis vitalba).

International: Old man’s beard is native to Europe and is reported as naturalized in Ireland, Poland, Sweden, Norway and other areas bordering its native range.  It is also naturalized in parts of North America, Australia and New Zealand. (Invasive species compendium: CABI Database: Clematis vitalba)

The risk Old man’s beard would pose to California is evaluated below.

Consequences of Introduction: 

1) Climate/Host Interaction: Old man’s beard is a warm temperate species. It grows on well-drained, moderately fertile and moist soils. In gardens, it responds well to the application of lime, but it is not restricted to calcareous sites in the wild. It is generally found in areas where annual rain fall is greater than 800 mm. California coastal areas with moist soils and heavy precipitation during the winter months can be at a risk for this invasive plant to establish. Risk is Medium (2).

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

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

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

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

2) Host Range: Old man’s beard is capable of growing in variety of habitats and on a number of substrates including trees and shrubs on forest margins, riverbanks, fence lines, dunes, hedgerows, grasslands and even in urban areas. (Invasive species compendium: CABI Database: Clematis vitalba). It has been observed recently near creeks, slopes and forest areas along California coast. Risk is High (3).

Evaluate the host range of the pest. Score: 3

– 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: Old man’s beard is pollinated by wind and insects. It can produce up to 100,000 seeds per plant and seeds can remain viable up to five years. (Kings County Noxious Weed Control Program). Seeds can be spread by wind, water, humans and animals. It can also spread by fragmentation when roots are produced from both separated and attached stem fragments. This weed can be accidentally spread along road sides by turbulence created by moving motor vehicles. Additionally, it has been introduced intentionally as an ornamental plant (Invasive species compendium: CABI database: Clematis vitalba). Risk is High (3).

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

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

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

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

4) Economic Impact:  Old man’s beard is a host of Alfalfa mosaic virus (Polak, 1986). There may be an increased risk of disease transmission by Clematis vitalba near vineyards. It has been regarded as a minor weed in European vineyards as well as a weed of pine plantations (Mitchell, 1975). Old man’s beard is poisonous to grazing livestock animals (West, 1991). Risk is High (3).

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

Economic Impact: A, B, E, F

A. The pest could lower crop yield.

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

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

D. The pest could negatively change normal cultural practices.

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

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

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

Economic Impact Score: 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: Infestation with Old man’s beard reduces biodiversity by blocking the light and out-competing native plants and trees. This could cause extirpation of local species that have restricted distributions. Its vines can form a dense, light absorbing canopy that suppresses all vegetation it climbs. Its vigorous growth and heavy weight can break the trees beneath it, leaving previously heathy forest a low, long-lived thicket of vines. (Global Invasive Species Database). Damage from old man’s beard can enhance invasion of native habitats by other invasive plants. As it occurs on public land, its presence will lead to treatment programs. Risk is High (3).

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 could significantly impact 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 Old man’s beard: High (14)

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: Old man’s beard has a limited distribution in Marin County and has been observed sparsely in Santa Cruz and San Francisco counties (Consortium of California Harbaria). Score: -1

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:

Old man’s beard may not spread and get established in drier areas of California but has it has a strong ability to grow and spread in the coastal areas with ample moisture and higher than average precipitation. It has not yet spread to vineyards and pine plantations in California, but has done so in Europe.

Conclusion and Rating Justification:

Old man’s beard has been recognized as a threat in Oregon and Washington. The fact that it has been observed multiple times, growing in the areas of Marin and Santa Cruz counties indicates that it can spread and get established in coastal areas of the California. An “A” rating is proposed at this time for this invasive weed, as it can still be eradicated from California.

References:

Plants Profile of Clematis vitalba (evergreen clematis), Accessed:10/06/2016 http://plants.usda.gov/core/profile?symbol=CLVI6

West CJ, 1991. Literature review of the biology of Clematis vitalba (old man’s beard). DSIR Land Resources Vegetation Report No. 725. Library@landcareresearch.co.nz.

Invasive Species Compendium- Clematis Vitalba, Accessed:10/06/2016 http://www.cabi.org/isc/datasheet/14280

Kings county Noxious Weed Control Program: Best Management Practices- Old Man’s Beard http://your.kingcounty.gov/dnrp/library/water-and-land/weeds/BMPs/Old-mans-beard-Clematis-vitalba-control.pdf

Plants for a Future: Clematis vitalba; Accessed: 10/06/2016 http://www.pfaf.org/user/Plant.aspx?LatinName=Clematis+vitalba

Cal Flora: Clematis vitalba; Accessed: 10/06/2016 http://www.calflora.org/cgi-bin/county_taxon.cgi?where-calrecnum=8710

Consortium of California Harbaria: Accessed 10/20/2016 http://ucjeps.berkeley.edu/consortium/

California Agriculture; University of California Agricultural and Natural Resources http://calag.ucanr.edu/Archive/?article=ca.v068n03p89

Global Invasive species database http://www.iucngisd.org/gisd/species.php?sc=157

Mitchell AF, 1975. Three forest climbers, Ivy, old man’s beard, and honeysuckle. Forestry Commission Forestry Record, HM Stationery Office, 1-12

Polak Z, 1996. Spontaneous hosts of alfalfa mosaic virus ascertained in ruderal plant associations in central Bohemia. Ochrana Rostlin, 32:161-165

Pest and Damage Records Database: Plant Health and Pest Prevention Services, California Department of Food and Agriculture, Assessed: 10/19/2016

Distribution of Climatis vitalba: Discover Life: Global Mapper- Global Biodiversity Information Facility. http://www.discoverlife.org/mp/20m?kind=Clematis+vitalba

Dist-of-Climatis-vitalba

Responsible Party:

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

Pest Rating: A  |  Proposed Seed Rating: P

Posted by ls

Weeds

Gymnocoronis spilanthoides | Senegal tea plant

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

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

History & Status:

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

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

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

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

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

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

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

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

Consequences of Introduction:

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

Score: 3

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

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

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

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

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

Score: 3

Evaluate the host range of the pest.

Low (1) has a very limited host range.

Medium (2) has a moderate host range.

High (3) has a wide host range.

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

Score: 3

Evaluate the natural and artificial dispersal potential of the pest.

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

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

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

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

Score: 2

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

A. The pest could lower crop yield.

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

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

D. The pest could negatively change normal cultural practices.

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

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

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

Score the pest for Environmental Impact:

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

Medium (2) causes 2 of these impacts.

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

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

Score: 3

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

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

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

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

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

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

   Score the pest for Environmental Impact:

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

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

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

Consequences of Introduction to California for Senegal tea plant:

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

Low = 5-8 points

Medium = 9-12 points

High = 13-15 points

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

Score: 0

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

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

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

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

Final Score:

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

Uncertainty:  

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

Conclusion and Rating Justification:

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

References:

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

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

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

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

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

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

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

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

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

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

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

WorldwideDistribution-Gymnocoronis-spilanthhoides

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

Responsible Party:

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

Pest Rating: A |  Proposed Seed Rating: P

Posted by ls 

Weeds

Parthenium hysterophorus L. | Santa Maria feverfew

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

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

Synonym:

Parthenium lobatum Buckley

History & Status:

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

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

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

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

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

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

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

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

Consequences of Introduction: 

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

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

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

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

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

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

Evaluate the host range of the pest.

Low (1) has a very limited host range.

Medium (2) has a moderate host range.

High (3) has a wide host range.

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

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

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

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

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

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

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

A. The pest could lower crop yield.

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

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

D. The pest could negatively change normal cultural practices.

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

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

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

Score the pest for Environmental Impact:

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

Medium (2) causes 2 of these impacts.

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

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

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

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

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

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

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

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

   Score the pest for Environmental Impact:

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

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

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

Consequences of Introduction to California for Santa Maria feverfew:

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

Low = 5-8 points

Medium = 9-12 points

High = 13-15 points

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

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

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

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

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

Final Score:

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

Uncertainty:

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

Conclusion and Rating Justification:

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

References:

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

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

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

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

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

National Plant Germplasm System: GRIN database: USDA APHIS

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

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

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

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

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

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

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

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

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

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

Pest Rating: A |  Proposed Seed Rating: P

Posted by ls 

Weeds

Giant Knotweeds | Fallopia japonica, F. sachalinensis, & F. X bohemica

California Pest Rating for
Giant knotweeds |  Fallopia japonica, F. sachalinensis, & F. X bohemica
Pest Rating: A |  Proposed Seed Rating: R
PEST RATING PROFILE
Initiating Event:

Japanese and giant knotweeds have been listed as A rated plants by CDFA for  many years. Bohemian knotweed has a Q rating.

History & Status:

Background: The giant knotweeds comprise 2 species and their hybrid: Japanese knotweed (F. japonica), giant knotweed (F. sachalinensis), and Bohemian knotweed (F. X bohemica).  They are large bamboo-like herbs to over 4 m tall under ideal conditions. They spread via underground rhizomes and can form extensive patches that exclude other vegetation. Where well adapted, they can spread via seed as well.  They produce copious biomass in areas with a year-long supply of soil moisture, and often overtop surrounding vegetation. This changes the shade profile, competitive environment, and hydrology of the community. Older stands are quite dense and can impede water flow along streams. Originally imported as an ornamental screen or hedge plant, giant knotweeds are native to Asia. In North America, this plant is not held in check by natural enemies and is capable of thriving and spreading in a wide range of conditions, especially riverbanks, roadsides and other moist, disturbed areas.

Giant knotweed is the biggest of the three species, sometimes exceeding 16 feet in height. The stems are smooth, hollow and light green, resembling the canes of bamboo, and sparingly branched. The leaves are 6 to 16″ long, with a deeply heart-shaped base and a blunt leaf tip. Diagnostic hairs on the leaf underside are long, thin and wavy. Giant knotweed has been declared noxious in California, Oregon, and Washington. Japanese knotweed is smaller (to 8’) and has hairless leaves. It has has been declared noxious in Alabama, California, Oregon, Vermont, and Washington. Bohemian knotweed is intermediate between the parents. Despite its hybrid origin, Bohemian knotweed produces fertile seed that can spread the plant. As it has often been misidentified, the range of Bohemian knotweed is likely larger than is recognized currently.

Official Control: Several counties in California have controlled giant knotweeds where they are found.

Worldwide Distribution: Giant knotweeds are native to Japan and Eastern Asia. They  heave been widely planted and escaped in all but the driest regions of North America.

California Distribution: Giant knotweeds are known from detected populations scattered throughout the state. Most of these represent planted plants that have spread vegetatively. Giant knotweeds can spread best, both vegetatively and by seed, in Northwestern California, especially Humboldt and Siskiyou Counties.

This risk giant knotweeds pose to California is evaluated below.

Consequences of Introduction: 

1) Climate/Host Interaction: Evaluate if the pest would have suitable hosts and climate to establish in California. Score: 2

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

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

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

Risk is Medium (2) as illustrated by the moist habitat of the plant in states where it occurs. Giant knotweeds are expected to colonize riparian areas, pond margins, wetlands, roadside ditches, irrigation canal banks, and moist forest edges. They will also spread in neglected gardens and urban waste areas.

2) Known Pest Host Range: Evaluate the host range of the pest. Score: 3

– Low (1) has a very limited host range.

– Medium (2) has a moderate host range.

– High (3) has a wide host range.

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

3) Pest Dispersal Potential: Evaluate the natural and artificial dispersal potential of the pest. Score: 3

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

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

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

Risk is High (3) as the plant spreads via water flow, human dispersal, and by seed in favorable regions.

4) Economic Impact: Evaluate the likely economic impacts of the pest to California using the criteria below. Score: 2

A. The pest could lower crop yield.

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

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

D. The pest could negatively change normal cultural practices.

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

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

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

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

– Medium (2) causes 2 of these impacts.

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

Risk is Medium (2) as the plants regrow very rapidly and often invade fallow fields and meadows. Pulling or digging out the weed has some effect if repeated regularly. All waste plant material must be burnt, as Japanese knotweed can survive composting. Burning the plant in situ is ineffective. Sheep, goats, cattle and horses will graze the young shoots.

5) Environmental Impact:  Evaluate the environmental impact of the pest on California using the criteria below.

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

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

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

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

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

Score the pest for Environmental Impact. Score: 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.

Risk is High (3) as the plant can dominate wetland habitats that are particularly important for native species, including sensitive species. In addition, the plant changes the profile and disrupts natural communities. It often triggers treatment programs. It is highly invasive in urban areas and in ornamental plantings.

Consequences of Introduction to California for giant knotweeds:

Add up the total score and include it here. (13)

–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. (-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:

7) The final score is the consequences of introduction score minus the post entry distribution and survey information score: (12)

Uncertainty:

Giant and Japanese knotweeds are invasive in favorable habitats in CA. Bohemian knotweed can be expected to act like its parents. Therefore, uncertainty is low.

Conclusion and Rating Justification:

Bad weeds of horticultural areas, waste areas, and marginal wetlands. They deserve an A rating. The chance of eradication is moderate to high.

Literature:

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.

Beerling, D. J., J. P. Bailey, and A. P. Conolly. 1994. Fallopia japonica (Houtt.) Ronse Decraene. J. Ecol. 82: 959-979.

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.

Stone, Katharine R. 2010. Polygonum sachalinense, P. cuspidatum, P. × bohemicum. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer): http://www.fs.fed.us/database/feis/

Zika, P. F. and A. L. Jacobson. 2003. An overlooked hybrid Japanese knotweed (Polygonum cuspidatum × sachalinense; Polygonaceae) in North America. Rhodora 105: 143-152.

Responsible Party:

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

Pest Rating: A |  Proposed Seed Rating: R

Posted by ls

Weeds

Parrotfeather Myriophyllum aquaticum (Vell.) Verdc.

California Pest Rating
Parrotfeather Myriophyllum aquaticum (Vell.) Verdc.
Saxifragales; Haloragaceae
Pest Rating: C |  Proposed Seed Rating: R
PEST RATING PROFILE
Initiating Event:

This plant was given a Q rating by the CDFA botany lab in 2015.

History & Status:                                  

Parrotfeather is originally from South America and has been introduced into several continents because of its popularity as a pond plant. Parrotfeather has established in bodies of water in California where it forms very dense mats of vegetation.

Parrotfeather is a perennial rooted aquatic plant that has both submersed and emergent forms. Branched stems grow up to 2 m long and 5 mm in diameter. Emersed branch networks form a horizontal pattern with extensive lateral branching followed by vertical growth. Emergent leaves are arranged in whorls of 3 to 6 leaves around the stem. The leaves themselves are divided, giving them a feathery appearance. Tiny, white flowers are produced on short stalks at the base of emergent leaves. In North America only female plants are known. Adventitious roots emerge from the stem nodes allowing the plants to grow vegetatively. The plants die back to rhizomes during the winter.

Official Control: Parrotfeather is listed as a noxious weed in Alabama, Connecticut, Maine, Massachusetts, Vermont, and Washington

Worldwide Distribution: Parrotfeather is native to South America. It has been introduced to Southeast Asia, Australia, New Zealand, South Africa, Japan and North America.

United States Distribution: Parrotfeather has been introduced to all states except the Interior West and the Central Northern States.

California Distribution:  Parrotfeather occurs in at least 27 California counties distributed throughout the state. As aquatic plants are under-collected and many water column weeds are superficially similar, it is likely more widely distributed than these collections indicate.

California Interceptions. Sent to CDFA by land managers.

Consequences of Introduction: 

1) Climate/Host Interaction: Evaluate if the pest would have suitable hosts and climate to establish in California. Score: 3

– 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.

Risk is High (3). Although open water habitat is sparse in CA, Parrotfeather has been able to spread to at least half the counties in the state. It has shown the ability to spread wherever appropriate habitat is available. Parrotfeather grows in slow-moving freshwater lakes, ponds, streams, and ditches; it responds well to high nutrient environments, where it grows in shallow water and on wet soil along shorelines; it is tolerant of moderate water fluctuations. It prefers freshwater but tolerates some salinity, so it could colonize wide areas in the CA Delta Region. Parrotfeather grows best in shallow water environments in which light reaches the bottom, but it can occur as a floating plant in the deeper waters of lakes. Parrot feather appears to prefer warmer, milder climates but is not seriously affected by frost. Once established, Parrotfeather persists despite variations in the environment.

2) Known Pest Host Range: Evaluate the host range of the pest. Score: 3

– Low (1) has a very limited host range.

– Medium (2) has a moderate host range.

– High (3) has a wide host range.

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

3) Pest Dispersal Potential: Evaluate the natural and artificial dispersal potential of the pest. Score: 3

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

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

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

Risk is High (3). Only female plants have been detected in North America, but like other water column plants, Parrotfeather grows and spreads extensively via vegetative means. Any small fragment can grow into a new colony if it reaches the appropriate shallow water habitat. As this plant is a popular pond plant, accidental and purposeful dissemination by hobbyists is a major pathway of spread.

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

A. The pest could lower crop yield.

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

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

D. The pest could negatively change normal cultural practices.

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

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

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

– 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.

Risk is High (3) as the dense growth can lead to flooding problems, impede irrigation, and obstruct recreational activities including boating, fishing, and swimming. It is a known weed of rice paddies, reducing yields. Parrotfeather has also been shown to provide excellent habitat for mosquito larvae; mosquitoes spread West Nile and zika viruses.

5) Environmental Impact: Evaluate the environmental impact of the pest on California using the criteria below.

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

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

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

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

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

Score the pest for Environmental Impact. Score: 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.

Risk is high (3) as Parrotfeather has escaped cultivation and has spread into water bodies through intentional plantings and growth of plant fragments. The brittle nature of stems results in many fragments; these root easily in moist soils to establish new colonies. Plant fragments with their robust leaves and stems, and thick waxy cuticle, can survive periods out of water. Fragments can spread by currents, water fowl, and by boats. Parrot feather is present year round and may provide cover but has very little food value for wildlife. Its dense growth leads to competition with native vegetation and could impact sensitive species such as Bogg’s Lake hedge hyssop (Gratiola heterosepala), Lobb’s buttercup (Ranunculus lobbii), and Gambell’s watercress (Rorippa gambelii).

Consequences of Introduction to California for Uruguayan water primrose:

Add up the total score and include it here. (15)

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: -3

–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:

7) The final score is the consequences of introduction score minus the post entry distribution and survey information score: Medium (12)

Uncertainty:

There is low uncertainty, as the plant has established in California and other states.

Conclusion and Rating Justification:

A widespread and potentially significant weed in CA of both natural wetlands and irrigation canals. Nevertheless, its wide distribution in CA and its availability in the aquarium and pond plant trade render it unlikely that regulation of its sale would be effective. It deserves a C rating, as it has spread widely through California. Eradication is impossible at this point in time.

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.

Bossard, C.C., J.M. Randall, M.C. Hoshovsky, M.C. 2000. Invasive plants of California’s wildlands. University of California Press, Berkeley, California.

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

Chambers, P.A., J.W. Barko, C.S. Smith. 1993. Evaluation of invasions and declines of submersed aquatic macrophytes. Journal of Aquatic Plant Management 31: 218-220.

USDA, NRCS. 2015. The PLANTS Database (http://plants.usda.gov, 18 December 2015). National Plant Data Team, Greensboro, NC 27401-4901 USA.

Responsible Party:

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

Pest Rating: C |  Proposed Seed Rating: R

Posted by ls

Weeds

Bearded Creeper | Crupina vulgaris Pers. ex. Cass.

common-crupina_1459126-UtahStateUniv-bugwood-WEB
California Pest Rating for
Bearded creeper | Crupina vulgaris Pers. ex. Cass.
Asteridae: Asteraceae
Pest Rating: A | Proposed Seed Rating: P

 

PEST RATING PROFILE
Initiating Event:

This plant has been rated as “A” on the CDFA Plant Pest Rating list for many years.

History & Status:

Bearded creeper is a winter annual, with erect, openly branched flowering stems to 60 cm tall at maturity. Most germination occurs after the first significant rains of fall/early winter, but germination can continue throughout the rainy season. Fall germinating plants exist as basal rosettes until flowering stems bolt in spring. Rosette leaves wither as flowering commences in late spring/early summer. Bearded creeper is adapted to many environmental conditions, is highly competitive for water and nutrients, and often produces solid stands. This adaptation to various conditions may be because it has been introduced from several locations in southern Europe. Although not an aggressive species in its native habitats, its adaptation to rough grazing lands of the Mediterranean region renders it invasive in natural grasslands of western North America. Here it contributes to degradation of native plant communities, lower forage production and increased risk of soil erosion.

Official Control: As Bearded creeper has been an “A” listed noxious weed for years, most or all of the few historic localities have been treated and eradicated.

California Distribution:  Modoc Plateau, North Coast Ranges (Sonoma Co.); to 250 m (850 ft).

California Interceptions: Vouchered specimens are known from Modoc and Sonoma Counties.

United States: Bearded creeper is known also from Idaho, Oregon, and Washington.

International: Bearded creeper is native to Europe. It is reported as naturalized and as an environmental weed in Canada.

This risk Bearded creeper would pose to California is evaluated below.

Consequences of Introduction: 

1) Climate/Host Interaction: The plant has adapted to a wide range of habitats in its native range and is demonstrated to have had multiple introductions into Western North America. Therefore bearded creeper receives a High (3) in this category.

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

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

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

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

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

Evaluate the host range of the pest. Score:

– Low (1) has a very limited host range.

– Medium (2) has a moderate host range.

– High (3) has a wide host range.

3) Pest Dispersal Potential: Bearded creeper produces via numerous seeds that seem to be able to spread rather slowly. The seed bank is moderately persistent. Once established, bearded creeper can persist and has proven difficult to eradicate. Bearded creeper 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: Bearded creeper can lower range productivity, land value, and can trigger state quarantines. Bearded creeper receives a High (3) in this category.

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

A. The pest could lower crop yield.

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

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

D. The pest could negatively change normal cultural practices.

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

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

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

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

– Medium (2) causes 2 of these impacts.

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

5) Environmental Impact: Bearded creeper is likely to trigger new chemical treatments by ranchers and land managers. The plant can dominate grassland and vernal pool areas, excluding native plants and lowering biodiversity. Rare taxa that might be affected include grassland species such as showy Indian clover (Trifolium amoenum), CA filaree (California macrophylla), and vernal pool species such as Burke’s goldfields (Lasthenia burkei) and CA tiger salamander (Ambystoma californiense). The plant can disrupt natural communities and exclude cultural plants from a landscape. Bearded creeper receives a High (3) in this category.

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

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

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

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

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

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

Score the pest for Environmental Impact. Score:

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

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

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

Consequences of Introduction to California for Bearded creeper: High (14)

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: Bearded creeper has been found in in 2 counties in California. 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: High (13)

Uncertainty:

Limited dispersability and fast treatment response has restricted bearded creeper’s spread so far in CA. However, it has shown great ability to spread if neglected, as in OR & ID.

Conclusion and Rating Justification:

A very bad weed. Deserves an A rating as all known populations have been treated. Chances of state eradication are high with sustained efforts.

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 (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.

Garnatje, T., R. Vilatersana, C. T. Roché, N. Garcia-Jacas, A. Susanna & D. C. Thill. 2002. Multiple introductions from the Iberian peninsula are responsible for invasion of Crupina vulgaris in western North America. New Phytologist 154: 419-28.

Invasive Species Compendium; Crupina vulgaris: http://www.cabi.org/isc/datasheet/13697

Thill, D.C., C.T. Roche and D.L. Zamora. 1999. Common crupina. Pp. 189-201. In, Biology and Management of Noxious Rangeland Weeds. Eds. R.L. Sheley and J.K. Petroff, Oregon State Univ. Press, Corvallis.

Responsible Party:

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

Comment Period:

The 45-day comment period opened on July 8, 2016 and closes on Aug 22, 2016.

Comment Format:

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

Example Comment: 

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

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♦  Comments may not be posted if they:

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

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

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

Pest Rating: A | Proposed Seed rating: P

Posted by ls

Weeds

Dagger-flower | Mantisalca salmantica (L.) Briq. & Cavill.

California Pest Rating for
Dagger-flower | Mantisalca salmantica (L.) Briq. & Cavill.
Synonym: Centaurea salmantica L.
Asterales: Asteraceae
Pest Rating: A |  Proposed Seed Rating: P
PEST RATING PROFILE
Initiating Event:

This plant has been rated as “Q” by CDFA since it was detected in a dried plant arrangement in 2015.

History & Status:

Dagger-flower is a perennial or biennial knapweed native to the Mediterranean Region including Israel, Morocco, and Mallorca. It has spread to Switzerland, Britain, Germany, and southern Scandinavia as a result of anthropogenic disturbance. It occupies disturbed areas, roadsides and rocky areas.

It is occasionally found as a grain or bird seed casual introduction. It is adventive on several continents, although it has not yet become a significant weed of agriculture except in Europe adjacent to its original range.

Official Control: None.

California Distribution:  A single collection from Healdsburg (Sonoma County) is known from 1896. Evidently it did not persist.

California Interceptions: It was submitted to the CDFA botany laboratory in a dried plant arrangements (PDRs #19TP06465296, 130P06398197, 490P06380234, & 500P06138704).

United States: In addition to California, Dagger-flower has been collected once or twice in Arizona as a waif.

International: Dagger-flower is native to the Mediterranean. It is reported as naturalized and as an environmental weed in South Africa. It is also sparingly introduced into Australia and Asia.

This risk Dagger-flower would pose to California is evaluated below.

Consequences of Introduction: 

1) Climate/Host Interaction: Evaluate if the pest would have suitable hosts and climate to establish in California. Score: 3

– 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.

Risk is High (3), as the plant is native to an area with a very similar climate. It is very widespread in this area and has spread north in response to human disturbance.

2) Known Pest Host Range: Evaluate the host range of the pest. Score: 3

– Low (1) has a very limited host range.

– Medium (2) has a moderate host range.

– High (3) has a wide host range.

Risk is high (3) as weeds do not require any one host, but grow wherever ecological conditions are favorable.

3) Pest Dispersal Potential: Evaluate the natural and artificial dispersal potential of the pest. Score: 2

– 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.

Risk is Medium (2). The plant produces via numerous seeds that seem to be able to spread rather slowly. The seed bank is moderately persistent.

4) Economic Impact: Evaluate the likely economic impacts of the pest to California using the criteria below. Score: 2

A. The pest could lower crop yield.

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

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

D. The pest could negatively change normal cultural practices.

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

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

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

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

– Medium (2) causes 2 of these impacts.

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

Risk is Medium (2) as the plant could lower range productivity, invade row crops, and could negatively change normal cultural practices.

5) Environmental Impact: Evaluate the environmental impact of the pest on California using the criteria below.

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

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

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

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

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

Score the pest for Environmental Impact. Score: 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.

Risk is high (3) as the plant could dominate roadsides and invade rangelands as happened with the closely related yellow star-thistle, excluding native plants and lowering biodiversity. If it were to spread in CA, the plant could disrupt natural communities and exclude cultural plants from a landscape.

Consequences of Introduction to California for Dagger-flower:

Add up the total score and include it here. (13)

–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. Detected once in CA but disappeared.

–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

7) The final score is the consequences of introduction score minus the post entry distribution and survey information score: (13)

Uncertainty:

High. This plant has had the opportunity to invade North America, but it has not succeeded so far. However, the behavior of some of its close relatives, as well as its ability to spread following human disturbance point to a high chance of spread once the species established in CA. Despite 2 known historic detections in the SW U.S., this has not happened.

Conclusion and Rating Justification:

A potentially bad weed. Deserves an A rating as several of its relatives are weeds in California and it comes from a very similar climate. As it is not yet established in California, a conservative approach to exclusion is justified.

References:

Alanen, A., T. Bongard, E. Einarsson, H. Hansen, L. Hedlund, K.Jansson, M. Josefsson, M. Philipp, O. T. Sandlund, A. E. Svart, H. E. Svart, & I. Weidema. 2004. Introduced Species in the Nordic Countries (Denmark) under Nordic Council of Ministers (NMR), subgroup Natur-og Friluftslivsgruppen.

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.

Bromilow, C. 1995. Problem Plants of South Africa. Briza Publications, Arcardia, South Africa.

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.

Hanf, M. 1983. The Arable Weeds of Europe, with their seedlings and seeds. BASF Aktiengesellschaft, D-6700 Ludwigshafen. Germany.

Holm, L. G., Pancho, J. V., Herberger, J. P. and Plucknett, D. L. 1979. A Geographical Atlas of World Weeds. John Wiley and Sons New York, USA.

Susana, A., N. Garcia-Jacas, O. Hidalgo, R. Vilatersana, & T. Garnatje. 2006. The Cardueae (Compositae) Revisited: Insights from ITS, trnL-trnF, & matK Nuclear and Chloropolast DNA Analysis. Annals of the Missouri Botanic Garden. 93: 150-171.

Responsible Party:

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

Pest Rating: A |  Proposed Seed Rating: P

Posted by ls 

Weeds

Jointed Bulrush | Schoenoplectus articulatus (L.) Palla

California Pest Rating for
Jointed bulrush  |  Schoenoplectus articulatus (L.) Palla
Family: Cyperaceae
Synonym: Scirpus articulatus L.
Pest Rating: D |  Proposed Seed Rating: N/A
PEST RATING PROFILE
 Initiating Event:

This plant recently has been detected in dried flower arrangements coming from India to California.

History & Status:

Jointed bulrush is an annual or perennial grass-like plant that has the ability to grow in both flooded and moist, upland conditions; this makes it a widespread wetland plant throughout the paleotropics. It has also been noted as a weed in rice. Seedling emergence can occur in both saturated and aerobic-moist soil, demonstrating that this plant does not require a saturated soil and that it can emerge from a moist soil. Jointed bulrush is not yet known from California, but it is considered a weed of rice in India where it is native. It can be distinguished from California native species of Schoenoplectus by the spikelets being clustered near the base of the stem, rather than near the apex.

Official Control: None in California. It is used as an element in dried plant arrangments from India and Southeast Asia.

California Distribution:  Jointed bulrush does not occur in California at this time.

California Interceptions: One detection (PDR #19TP06465285) attached to a shipment of a dried plant arrangement from India that came through Virginia.

The threat that Jointed bulrush would pose to California is evaluated below.

Consequences of Introduction: 

1) Climate/Host Interaction: Evaluate if the pest would have suitable hosts and climate to establish in California. Score: 1

– 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.

Risk is low (1), as the plant occurs in tropical wetlands only. Our rice fields are in colder areas and the subtropical area of California has little of the potential habitat.

2) Known Pest Host Range: Evaluate the host range of the pest. Score: 3

– Low (1) has a very limited host range.

– Medium (2) has a moderate host range.

– High (3) has a wide host range.

Risk is high (3) as weeds do not require any one host, but grow wherever ecological conditions are favorable.

3) Pest Dispersal Potential: Evaluate the natural and artificial dispersal potential of the pest. Score: 2

– 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.

Risk is Medium (2). The plant produces via numerous seeds and spreads in water. This might limit the speed of its spread. It could also be spread via the pathway of untreated fruiting stems being included in dried floral arrangements. Effective treatment of such plant material before entry into the U.S. would prevent any such accidental introduction.

4) Economic Impact: Evaluate the likely economic impacts of the pest to California using the criteria below. Score: 2

A. The pest could lower crop yield.

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

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

D. The pest could negatively change normal cultural practices.

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

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

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

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

– Medium (2) causes 2 of these impacts.

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

Risk is Medium (2) as the plant can lower crop yields and force changes in cultural practices where it is established.

5) Environmental Impact: Evaluate the environmental impact of the pest on California using the criteria below.

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

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

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

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

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

Score the pest for Environmental Impact. Score: 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.

Risk is Medium (2) as, once established, it could conceivably invade the water systems of southern California and disrupt natural wetland communities.

Consequences of Introduction to California for Jointed bulrush:

Add up the total score and include it here. (10)

–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 yet established in CA.

–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

7) The final score is the consequences of introduction score minus the post entry distribution and survey information score: (12)

Uncertainty:

Uncertainty is relatively high. Jointed bulrush is not naturalized in California yet, It’s current weediness seems restricted to rice fields in tropical areas. Nevertheless, other wetland weeds have surprised us by invading areas colder than their native range. Any detection of Jointed bulrush in the ambient environment in CA should prompt a reevaluation of its potential risk.

Conclusion and Rating Justification:

A potential weed in wet areas of the tropics, this plant is unlikely to establish in CA. This plant deserves a D rating as it is unlikely to be invasive in CA, although it is a rice field weed in its native range of India. Due to the paucity of references to its weediness, Jointed bulrush does not seem to be as destructive as some other rice field weeds.

References:

Baskin, C. C. & J. M. Baskin. 2001. Chapter 11: Plants with Specialized life-cycles or habitats in Seeds: Ecology, Biogeography, and Evolution of Dormancy and Germination. Academic Press (Elsevier). San Diego, California.

Bopal, B. 1991. Ecology and management of aquatic vegetation in the Indian subcontinent. Kluwer International Press. Dordrecht, Netherlands.

Moody, K. 1989. Weeds Reported in Rice in South and Southeast Asia. International Rice Research Institute. Manila, Philippines.

Shanker, C. 2013. Flora from Cuttack for ID. Efloraofindia Internet site accessed on 5/15/2016:

https://groups.google.com/forum/?hl=en-GB#!topic/indiantreepix/UQk-KIWRfEo

Responsible Party:

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

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

Posted by ls

Weeds

Salsola tragus L.: Russian-thistle

California Pest Rating for
Salsola tragus L.: Russian-thistle
Caryophyllidae; Chenopodiaceae
Pest Rating: C  |  Proposed Seed Pest Rating: R
PEST RATING PROFILE
Initiating Event:

This plant has been rated as “C” on the CDFA Plant Pest Rating list and was recently assigned a Q rating by the botany lab.

History & Status:

Russian-thistle is a densely-branched, sub-shrubby annual, to about 1 m tall, with inconspicuous flowers and 5-winged fruits. Fruiting plants die and detach from their roots, forming a “tumbleweed” that tumbles over the ground, dispersing the single-seeded fruits far and wide. Russian-thistle is part of the confusing taxonomic complex that is native to the Old World and Australasia. In the current Jepson Manual, a narrow species interpretation is accepted and our plants are recognized as Salsola tragus. Russian-thistle can act as an alternate host for the virus that causes curly-top in sugarbeets, tomatoes, and melons. Russian-thistle favors disturbed sites, silty dry sites, and saline desert areas; It was introduced into the United States in South Dakota in 1874 as a contaminant of flax seed.

Official Control:  Russian-thistle has been a “C” listed noxious weed by California.

California Distribution:  Russian-thistle is known from all areas of California except for the North Coast and adjacent mountains.

California Interceptions: Fruits of Russian-thistle are detected commonly in vehicles entering California.

United States: Russian-thistle has been found in all states except Alaska and Florida.

International: Russian-thistle is native to arid, disturbed, and saline areas of Eurasia.

This risk Russian-thistle poses to California is evaluated below.

Consequences of Introduction: 

1) Climate/Host Interaction: The plant is particularly adapted to hot interior zones but is widespread in many coastal areas as well. Its widespread distribution demonstrates its ability to occupy California. Therefore, Russian-thistle receives a High (3) in this category.

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

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

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

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

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

Evaluate the host range of the pest. Score:

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

3) Pest Dispersal Potential: Russian-thistle produces via numerous seeds that seem to be able to spread via the tumbleweed habit. Russian-thistle receives a High (3) 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: Russian-thistle invades cropland, as well as rangeland. It can also serve as a host for curly-top virus. In some instances, detached plants have impeded traffic traversing arid areas. Russian-thistle receives a High (3) in this category.

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

A.  The pest could lower crop yield

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

C.  The pest could trigger the loss of markets (includes quarantines by other states or countries)

D.  The pest could negatively change normal production cultural practices

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

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

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

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

5) Environmental Impact: Russian-thistle is likely to trigger new chemical treatments by ranchers and land managers. The plant can dominate subsaline areas or desert washes, excluding native plants and lowering biodiversity. Endangered taxa that might be affected include those that use arid areas such as the brittlescale (Atriplex depressa) and alkali mariposa-lily (Calochortus striatus). It might also reduce habitat value for endangered animals such as the giant kangaroo rat (Dipodomys ingens) by displacing food plants. The effect on local invertebrates is unknown, but the invertebrate fauna associated with Russian-thistle are unlikely to be as diverse as those that associate with native plants that are displaced by Russian-thistle. The plant can disrupt natural communities. Russian-thistle receives a High (3) in this category.

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

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

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

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

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

E.  Significantly impacting cultural practices, home/urban gardening or ornamental plantings.

Score the pest for Environmental Impact.

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

Consequences of Introduction to California for Russian-thistle: High (15)

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: Russian-thistle has been found in in all but 3 counties in California. 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 (12)

Uncertainty:

There is little uncertainty, as this is an invasive agricultural and environmental weed in California.

Conclusion and Rating Justification:

A terrible weed because of its ability to grow in arid poorly vegetated regions. Because it has spread throughout most or nearly all of its potential range, it merits a C rating.

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 Encycloweedia; Salsola tragus. Accessed 5/25/2015: http://www.cdfa.ca.gov/plant/ipc/encycloweedia/weedinfo/salsola.htm

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.

Longland, W. S. 1995. Desert rodents in disturbed shrub communities and their effects on plant recruitment. General Technical Report Intermountain Research Station, USDA Forest Service No. INT-GTR-315: 209-215.

U.S.D.A. Plants database. Salsola tragus. Accessed 5/24/2015:  http://plants.usda.gov/core/profile?symbol=SATR12

Responsible Party:

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

Pest Rating: C | Proposed Seed Pest Rating: R

Posted by ls