Barbwire Russian thistle | Salsola gobicola | Pest Rating Proposals and Final Ratings

California Pest Rating

Barbwire Russian thistle | Salsola gobicola

Family: Chenopodiaceae

Pest Rating: B | Proposed Seed Rating: R

PEST RATING PROFILE

Initiating Event:

Salsola gobicola has an internal CDFA rating of “Q”. A permanent pest rating proposal is required to support an official pest rating.

History & Status:

Background: Salsola gobicola is an annual herbaceous dicot that can grow 1.5 m tall¹. The genus Salsola belongs to the tribe Salsoleae of the family Amaranthaceae. Salsola means “salty” in Latin, referring its tolerance for salty soils. This genus has very large number of species, but only a few species appears as weeds in North America. These species includes Salsola tragus (probably the most widespread), Salsola collina (mainly east of the Rocky Mountains), Salsola paulsenii (primarily in deserts), Salsola kali (restricted to ocean shores) and Salsola australis (mainly in California, South Africa and Australia). Polyploid hybrids include Salsola x gobicola (a cross of S. tragus and S. paulsenii) that is known in the western USA and central Asia, and Salsola x ryanii (a cross of S. tragus and S. australis), known only from California⁴.

Salsola gobicola appears where the parent species overlap, in central Asia and the western USA. It is well distributed in sandy (120–2200 m) places in California. It has spreading to ascending stems and opposite to alternate, gray green to yellow green leaves. It has small flower, a green calyx and sepals’ soft to spiny. The flowering time is July to October⁶.

Worldwide Distribution: The genus Salsola is reported widespread in Europe and Asia. Salsola gobicola is only reported outside California in Utah and Mexico⁶.

Official Control: Salsola gobicola is not known to be under official control in any States or nations⁹.

California Distribution: It is reported form Imperial, Inyo, Kern, Lassen, Los Angeles, Mono, Riverside, San Bernardino, Riverside, San Luis Obispo and Tulare counties^{2, 7}.

California Interceptions: Salsola gobicola was intercepted three times between January 2010 and December 2116 by CDFA border protection stations. There were several vouchers were submitted before 2000’s⁸.

The risk Salsola gobicola (Barbwire Russian thistle) would pose to California is evaluated below.

Consequences of Introduction:

1) Climate/Host Interaction: Salsola gobicola is established large sandy area in California and still spreading². Therefore, it receives a High (3) in this category.

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

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

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

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

2) Known Pest Host Range: Salsola gobicola do not require any one host, but grow wherever ecological conditions are favorable. It receives a High (3) in this category.

Evaluate the host range of the pest. 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: Seed spreading via tumbling mature plants with air current is very common in this genus. The mature plants contain thousands of seeds ready to germinate in sandy, salty dry soil condition. Seed are also transported to long distances by cattle and human transport systems. It receives a High (3) in this category

Evaluate the natural and artificial dispersal potential of the pest.

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

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

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

4) Economic Impact: Salsola gobicola could invades the cropland, especially spring wheat by growing in dense stands. It decreases crop yield and can lower the crop value. It displaces both native plants and other plants which could negatively change normal cultural practices. It receives a High (3) in this category.

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

Economic Impact: A, B, D

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: Salsola gobicola is likely to trigger new chemical treatments by ranchers and land managers. A study shows that Salsola gobicola contributes population decline and had negative effect on the habitat of these two federally listed endangered species, the Eureka Valley dune grass (Swallenia alexandrae) and the Eureka Valley evening primrose (Oenothera californica ssp. Eurekensis)^3,5. It may also effect the rare taxa Mariposa lupine (Lupinus citrinus), Antioch dunes evening primrose (Oenothera deltoids spp. howellii) and grassland species such as California round leaved filaree (California macrophylla). The plant can disrupt natural communities. Salsola gobicola receives a High (3) in this category.

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

Environmental Impact: A B, C, D

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

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

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

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

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

Environmental Impact Score: 3

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

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

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

Consequences of Introduction to California for Salsola gobicola (Barbwire Russian thistle): High (15)

–Low = 5-8 points

–Medium = 9-12 points

–High = 13-15 points

6) Post Entry Distribution and Survey Information: Salsola gobicola has been reported in 12 counties in California. It receives a Medium (-2) in this category.

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

Score: -2

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

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

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

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

Final Score:

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

Uncertainty:

Salsola gobicola has been known in California for decades and it has proved highly invasive. So, there is low uncertainty.

Conclusion and Rating Justification:

Conclusions of the harm(s) associated with this pest to California using all of the evidence presented above: Proposed Rating: based on the score listed above the pest is a high risk weed with a distribution in at least 12 counties. A “B” rating is recommended, as the plant is invasive, but could spread further.

References:

Annual report 2009. Plant pest Diagnostics center. California Department of Food and Agriculture. Accessed January 05, 2017 https://www.cdfa.ca.gov/plant/ppd/PDF/PPDC2009.pdf

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 January 05, 2017 https://www.calflora.org/cgi-bin/species_query.cgi?where-calrecnum=12004

Chow, Elaine K. Ph D. 2016. Dynamics of Native and Invasive Non-native Plant Species in Desert Sand Dunes of Eureka Valley, Death Valley National Park. UC, DAVIS. 149 pages; 10182745. Accessed January 05, 2017 http://gradworks.umi.com/10/18/10182745.html

Invasive Species Compendium: Distribution maps for plant pests, Accessed January 05, 2017 http://www.cabi.org/cpc/datasheet/50297

Jane Cipra and Kelly Fuhrmann, 2012. Understanding endangered plant species population changes at Eureka Dunes, Death Valley National Park. Park science Volume 29. Accessed January 05, 2017 https://www.nature.nps.gov/parkscience/Archive/PDF/Article_PDFs/ParkScience29(1)SpringSummer2012_62-68_CipraFuhrmann_2874.pdf

Jepson Baldwin, B. G., D. H. Goldman, D. J. Keil, R. Patterson, T. J. Rosatti, and D. H. Wilken, editors. 2012. The Jepson manual: vascular plants of California, second edition. University of California Press, Berkeley. Accessed January 05, 2017 http://ucjeps.berkeley.edu/eflora/eflora_display.php?tid=82452

Roskov Y., Abucay L. Orrell T. Nicolson D. eds. 2015. The University of Georgia Center for invasive species and ecosystem health. Accessed January 05, 2017 https://www.eddmaps.org/Species/subject.cfm?sub=75312

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

USDA Phytosanitary Certificate Issuance & Tracking System (PCIT) Phytosanitary Export Database (PExD). Accessed January 05, 2017 https://pcit.aphis.usda.gov/pcit/

Responsible Party:

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

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