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Cheatgrass | Bromus tectorum

California Pest Rating for
Cheatgrass  Bromus tectorum
Pest Rating: C  |  Proposed Seed Rating: None
PEST RATING PROFILE
Initiating Event:

This plant is implicated in changing fire regimes in western states.

History & Status:

Cheatgrass is an annual grass. It is a tufted annual; although not large, it can colonize preferred habtat in large numbers, especially after disturbance.  The spikelets consist of several florest that are pendent at maturity. Cheatgrass can be grazed early in the year, but as it matures the spikey awns render it less suitable for this purpose. As such it is inferior to  perennial grasses in regards to livestock production. A survey of 11 western states in 1964 showed that cheatgrass was present on at least 60 million acres. Its range is larger now.

California Distribution: Cheatgrass  has been collected in all counties of California exept the driest deserts in the southeast of the state.

California Interceptions: Several vouchers have been submitted to CDFA for identification.

United States: Cheatgrass was introduced to North America independently several times via ship ballast, contaminated crop seed, and packing material. Cheatgrass now occurs throughout most of the United States, Canada, Greenland, and northern Mexico.

International:  Cheatgrass  is native to northern Africa, Europe, and western Asia. It is introduced in North and South America, Australia, New Zealand, Japan, and Iceland.

This risk Cheatgrass  would pose to California is evaluated below.

Consequences of Introduction:

1) Risk is high (3), as Cheatgrass is naturalized in the drier regions throughout western North America and is still spreading.

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: Cheatgrass seeds are light and produced prolifically. The awns on Cheatgrass fruits allow for long-distance dispersal in animal skin and fur. Motor vehicles also disperse Cheatgrass fruits. Cheatgrass can begin producing seeds at 3 weeks from germination or, given available water and nutrients, can bloom later in the season with many more flowers. It can germinate in the fall or winter depending on the year and the climate. Therefore, Cheatgrass 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: Cheatgrass has been used as forage in arid environments in the Intermontane West, and this is a positive economic value. It is less nutritious than the perennial bunchgrasses that it often replaced. When Cheatgrass invades new habitats, there is often an increase in fire that removes perennials, including grasses and sagebrush steppe shrubs from the area. Livestock browse shrubs as a source of protein in the late season. As shrubs are eliminated by fire, fall and winter digestible protein sources are lost. Cheatgrass is also a row crop weed, although this is less of an issue than its effects on rangeland.

Cheatgrass receives a High (3) in this category.

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

The pest could lower crop yield.

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

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

C.  The pest could negatively change normal cultural practices.

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

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

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

– Low (1) causes none of the above to occur.
– Medium (2) causes 2 of these impacts.
– High (3) causes 3 or more of these impacts.

5)  Environmental Impact: Cheatgrass invades and dominates a variety of vegetation types, especially sagebrush steppe. In natural areas, it tends to form dense swards that exclude native vegetation and increase the ability of fire to spread. In some arid regions, Cheatgrass can transform native sagebrush scrub into non-native grasslands. This, in turn, decreases the native biodiversity and removes habitat for wildlife including birds such as the species of concern Greater Sage Grouse (Centrocercus urophasianus) and its distinct population segment, the Bi-state Sage Grouse, as well as other sagebrush steppe endemics. Therefore, Cheatgrass 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 Cheatgrass: 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: Cheatgrass is regionally common in CA. It receives a High (-3) in this category.

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

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

Final Score:

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

Uncertainty:

This plant has been known in SW North America for over 100 years and it has proved highly invasive. So, there is low uncertainty.

Conclusion and Rating Justification:

Proposed Rating: based on the score listed above, cheatgrass is still spreading but has occupied the majority of its potential habitat in California. This plant has been invasive; in California it is already known from most counties. Because this plant is so widespread, a rating of C is justified.

References:

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

CalFlora: http://www.calflora.org/cgi-bin/species_query.cgi?where-calrecnum=12041

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

Pellant, M. 1996. Cheatgrass: the Invader That Won the West. Bureau of Land Management, Boise Idaho.

U.S. Forest Service. Cheatgrass. Accessed 8/20/2015:

http://www.fs.fed.us/database/feis/plants/graminoid/brotec/all.html

Young, J. A.  & C. D. Clements. 2007. Cheatgrass and Grazing Rangelands. Rangelands, 29:15-20.

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 Format:

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

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Pest Rating: C  |  Proposed Seed Rating: None

Posted by ls

Weeds

Spanish Mercury | Mercurialis ambigua

California Pest Rating for
Spanish Mercury  |  Mercurialis ambigua
Pest Rating: B  |  Proposed Seed Rating: R
PEST RATING PROFILE
Initiating Event:

This plant has been rated as “B” on the CDFA Plant Pest Rating list for 3 years

History & Status:

Spanish mercury is a modest annual herb with alternate, oval leaves. It has tiny flowers in short spikes in the axils of the leaves. In Flora Europaea Spanish mercury is included as a variant of dog mercury (Mercurialis annua), a European weed that has been found in the San Francisco Bay Area. In most Spanish floras the taxa are treated as distinct. Spanish mercury differs from dog mercury in its wider leaves, shorter flower spikes and in its polyploidy (multiple chromosome sets). It has been demonstrated that these hexaploid plants arose between a tetraploid M. annua (dog mercury) and a diploid M. huetii.  In addition to these differences, Spanish mercury may differ from dog mercury in its weedy behavior. In its natural habitat in Spain it occurs in open areas protected from the hottest sun with common weeds such as bristly oxtongue (Helminthostachys echioides), shining geranium (Geranium lucidum), purple false-brome (Brachypodium distachyon), ripgut brome (Bromus diandrus), hairy cress (Cardamine hirsuta), common chickweed (Stellaria media), sow-thistle (Sonchus oleraceus), mouse-ear chickweed (Cerastium glomeratum), bur-chervil (Anthriscus caucalis), common pimpernel (Anagallis arvensis), red brome (Bromus madritensis), and plumeless thistle, (Carduus tenuiflorus). Spanish mercury has shown itself to be very invasive in nursery situations. It has also been found in mulch adjacent to public buildings and on the edge of a vineyard.

Official Control: There is no known official control in California at this time.

California Distribution:  Because of the taxonomic confusion with dog mercury, Spanish mercury was not recognized in California until the 2000s. Nevertheless, its incursion seems to be rather recent, as older vouchered specimens are dog mercury. It is, so far, always limited in distribution. It has been found in Alameda, Contra Costa, Napa, Monterey, and Yolo Counties.

California Interceptions:  Spanish mercury has never been found coming into California.

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 naturalized in mulched landscapes, around nurseries and in vineyards. Once its population builds up it can be expected in areas occupied by the widespread weed associates mentioned above.

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). The plant produces numerous seeds that seem to be able to spread rather well via pathways that have to do with landscaping and nursery operations.

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). Based on the mercuries being known crop weeds on several continents, the plant is likely to interfere with crop production and can lower crop value. It shows an incipient ability to be a nuisance weed in gardens, especially in open garden beds.

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 open, disturbed areas, excluding other plants and lowering biodiversity and can exclude cultural plants from a landscape.

Consequences of Introduction to California for Spanish mercury:

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. (-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:

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

Uncertainty:

Annual mercuries are widespread as agricultural weeds throughout the world. Which of these is dog mercury versus Spanish mercury is unknown. Nevertheless, it seems to be actively spreading in Central California. The eventual effects are in the future and must be projected with significant uncertainty. The seeds of Spanish mercury are quite similar to those of dog mercury and identification of seed contaminants must reflect this uncertainty.

Conclusion and Rating Justification:

A potentially bad weed of horticultural areas, vineyards, and possibly open, grassy habitats. Deserves a B rating as it is present in > 5 cos.

References:

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

‪Fernández, I. F. 2001. Claves de Flora Iberica: Plantas Vasculares de la Península Ibérica e Islas Baleares, Volume 1. CSIS Press. Madrid.

Flora of Sierra de La Parra (Badajoz). Accessed 11/15/2015:

http://sierradelaparrabadajoz.blogspot.com

López G.B., M. C. Romero, B. Cabezudo, C. M. Torres, & C. Salazar. 2011.

Claves de la Flora Vascular de Andalucía Oriental. Universidad Almería.

Obbard, D. J., Harris, S. A., Richard J. A. Buggs, & Pannell, J. R. 2006. Hybridization, Polyploidy, and the Evolution of Sexual Systems in Mercurialis (Euphorbiaceae). Evolution 60: 1801–1815.

Thomas, R. G. 1958. Sexuality in Diploid and Hexaploid Races of Mercurialis annua L. Annals of Botany, N.S. 22: 55-72.

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: B  |  Proposed Seed Rating: R

Posted by ls

Weeds

Froelichia gracilis (Hook.) Moq.; Slender snakecotton

California Pest Rating for
Froelichia gracilis (Hook.) Moq.; Slender snakecotton
Amaranthaceae: Caryophyllales
Pest Rating: D  |  Proposed Seed Rating: None
PEST RATING PROFILE
Initiating Event:

The species was given a temporary Q rating in 2014.

History & Status:

Slender snakecotton is an herbaceous, short-lived perennial (often an annual in weedy situations) that can grow 20-70 cm in length. The plant branches from the base, creeping along the ground and then becoming erect. The whole plant is covered in white, silky hairs. The leaves occur mostly on the lowers parts of stems and are narrowly lanceolate, narrower than in closely related taxa. The largest leaves measure 8 cm (3 in.) long and 1 cm wide. The apetalous flowers of Froelichia gracilis are arranged in a 3-rowed spiral on 1-3 cm long spikes and appear in summer to early fall. The seeds of this plant are small, measuring 1.2-1.4 mm. Although widely distributed and native to the southern United States, slender snakecotton seems not to be native to California. It is a weedy species of roadsides, railroads, farms and pastures, riverbanks, vacant lots, overgrazed rangelands, and sandy soils. It tolerates cold winters, but can also occur in moist subtropical areas.

Official Control: Slender snakecotton has been a “Q” listed weed in California since late 2014.

California Distribution:  Slender snakecotton is known from 3 interceptions in California (two from Los Angeles and one from Shasta County).

California Interceptions: Vouchered specimens are known from Los Angeles and Shasta Counties.

United States:  Slender snakecotton is widespread in the Southern United States. It is generally viewed as adventive in the northern and northeastern U.S. It is listed as a noxious weed in Connecticut.

International: Slender snakecotton is reported as naturalized and as an environmental and agricultural weed in Queensland, Australia.

The risk Slender snakecotton would pose to California is evaluated below.

Consequences of Introduction: 

1) Climate/Host Interaction: It is an invasive species of roadsides, railroads, farms, riverbanks, vacant lots, overgrazed rangelands, and sandy areas. It is been detected in 2 counties with radically different climates, but has not spread widely. Although it may spread in agricultural situations with adequate water, its rarity in the state, despite being native to nearby states, indicates that it is unlikely to spread quickly. Therefore. It scores as Low (1) in this category.

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

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

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

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

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

Evaluate the host range of the pest. Score:

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

-Medium (2) has a moderate host range.

–High (3) has a wide host range.

3) Pest Dispersal Potential: Slender snakecotton produces numerous seeds that can spreads via agricultural activity. Slender snakecotton 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: Slender snakecotton is a weed in some agricultural situations. There is little report of significant effects however. Slender snakecotton receives a Low (1) in this category.

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

A. The pest could lower crop yield.

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

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

D. The pest could negatively change normal cultural practices.

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

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

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: The plant has not yet spread widely in California. If it does spread, Slender snakecotton might trigger new treatments by land managers. As it invades open areas, it may outcompete native plants that also colonize open, sandy soils. Slender snakecotton receives a Low (1) 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 could significantly impact 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 Slender snakecotton: Low (8)

Add up the total score and include it here.

-Low = 5-8 points

-Medium = 9-12 points

-High = 13-15 points

6)  Post Entry Distribution and Survey Information: Slender
snakecotton has been found in in 2 counties in California. Its range at this time is limited. 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.

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

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

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

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

Final Score:

The final score is the consequences of introduction score minus the post entry distribution and survey information score: Low (6)

Uncertainty:

The rarity of this plant in California despite being first detected in Los Angeles in 1955 and its widespread range in the rest of North America render it unlikely that this plant will invade many new areas and increase its density and acreage.

Conclusion and Rating Justification:

Slender snakecotton deserves an D rating at this time, because of its limited range in California, despite being native to nearby states.

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/

Csurhes S.  & Y. Zhou . 2008. Weed Risk Assessment of Cotton-tails, Froelichia floridana and F. gracilis. Biosecurity Queensland Department of Primary Industries and Fisheries, Brisbane, Australia.

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

Reed, C. F. 1962. New records for Froelichia in eastern United States. Castanea 27: 59-61.

USDA Plant Profile: Froelichia gracilis. Accessed May 16, 2015:

http://plants.usda.gov/core/profile?symbol=FRGR3

Washington State Weed Control Board: Slender snakecotton. Accessed September 16, 2014:

http://www.nwcb.wa.gov/detail.asp?weed=12

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: None

Posted by ls

Weeds

Enchylaena tomentosa R. Br.; Ruby saltbush

California Pest Rating for
Enchylaena tomentosa R. Br.; Ruby saltbush
Chenopodiaceae: Caryophyllales
Pest Rating: A  |  Proposed Seed Rating: R
PEST RATING PROFILE
Initiating Event:

The species was detected in San Diego County in 2014 and given a “Q” rating.

History & Status:

Ruby saltbush is an open, straggling shrub native to Australia that can grow up to 2 m tall and wide, but is usually much shorter. Grazing and low nutrient soils in full sun limit the height of the plant, but it is quite capable of clambering over adjacent vegetation. Leaf color in California specimens is dark blue-green. The leaves are succulent, 1-2 cm long, cylindrical, and may be hairy or smooth. Stems are distinctively marked with parallel lines. The flowers are small, occurring in the leaf axils. The sepals become fleshy and red when the fruit ripens, simulating a juicy berry.

Official Control: Ruby saltbush has not been subjected to official control.

California Distribution:  Ruby saltbush is known from a single infestation in Central San Diego County, California. The plants grow along a sloping road bank and an adjacent arroyo surrounded by residential development. As other vegetation along the road bank may be horticultural in origin, it seems likely that the plant was planted intentionally as a novel, low maintenance landscape shrub. The oldest known specimen in California was collected in 2014.

California Interceptions: Vouchered specimens are known from San Diego County, although they have not yet been accessioned.

United States:  Ruby saltbush is known only from California in the United States.

International: Ruby saltbush is native to Australia, where it is widely distributed in arid and semiarid areas in various shrubby or grassland plant communities. It is especially common in slightly saline soils. It is reported as naturalized in New Caledonia.

The risk Ruby saltbush would pose to California is evaluated below.

Consequences of Introduction: 

1) Climate/Host Interaction: The plant occurs in grassland and coastal scrub. It is spreading in ruderal areas near the coast. It is tolerant of slightly saline soils. Therefore, its adaptation to coastal habitats in southern California is likely high. It scores as Medium (2) in this category.

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

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

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

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

2) 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: Ruby saltbush produces numerous red, fleshy fruits that are typical of bird-dispersed woody plants. Hundreds to the low 1000s of fruits are produced by a mature shrub. Ruby saltbush 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: It has not yet had an impact on agricultural lands and future possible impacts are unknown. Ruby saltbush is browsed by livestock under adverse conditions, but its range value is not high. It receives a Low (1) in this category.

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

A. The pest could lower crop yield.

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

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

D. The pest could negatively change normal cultural practices.

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

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

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

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

-Medium (2) causes 2 of these impacts.

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

5) Environmental Impact: Ruby saltbush is overgrowing adjacent vegetation such as jojoba and prickly pear cactus; it is dense and its sprawling stems can smother other plants. In adjacent areas it is growing as scattered plants that may be suppressing other coastal scrub species through competition. Rare taxa that might be affected include strand species such as creeping lotus (Acmispon prostratus) and coastal scrub species such as California gnatcatcher (Polioptila californica). Because it forms dense patches, Ruby saltbush could interfere with recreation along the coast. Ruby saltbush 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 could significantly impact 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 Ruby saltbush: Medium (11)

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: Ruby saltbush has been found in in 1 locality in California; This may have spread from cultivation. It receives a Low (-1) in this category.

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

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

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

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

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

Final Score:

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

Uncertainty:

This plant is showing the ability to spread in disturbed areas near the coast. Its future potential impact on agriculture, if allowed to spread, is unknown.

Conclusion and Rating Justification:

This plant is just beginning its spread in California. It shows tendencies of invasiveness and it is strictly limited in distribution now. The probability of eradication is high. It should be given a rating of “A” to encourage attention to this plant.

References:

Calflora; Enchylaena tomentosa. Accessed 2/22/2015:                            http://www.calflora.org/cgi-bin/species_query.cgi?where-calrecnum=13047

Florabase; Enchylaena tomentosa. Accessed 2/22/2015: http://florabase.dpaw.wa.gov.au/browse/profile/2511

USDA Plants Database, Enchylaena tomentosa. Accessed 2/22/2015: http://plants.usda.gov/core/profile?symbol=ento3

Western Australia Department of Agriculture; ruby salt bush. Accessed 2/22/2015: https://www.agric.wa.gov.au/ruby-saltbush

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

Medicago scutellata (L.) Wilson; Snail Medic

California Pest Rating for
Medicago scutellata (L.) Wilson; Snail Medic
Fabales: Fabaceae
Pest Rating: D  |  Proposed Seed Rating: N/A
PEST RATING PROFILE
Initiating Event:

This plant has been rated as “Q” by the CDFA Botany Laboratory.

History & Status:

Snail Medic is an annual herb with trifoliate leaves and comparatively large (6-7 mm) fruits that spiral (hence the common name), but lack prickles. The leaves are softly hairy and inconspicuously glandular. Flowers are borne on stems shorter than the petioles in groups of 2-3. In California, it appears in disturbed areas.

Official Control:  None.

California Distribution:  Snail Medic is known from Butte, Santa Clara, Monterey, and San Luis Obispo Counties.

California Interceptions: Vouchered specimens are known from Butte, Santa Clara, Monterey, and San Luis Obispo Counties.

United States: Snail Medic has only been found in North America in Delaware outside of California.

International: Snail Medic is native to Europe.

This risk Snail Medic would pose to California is evaluated below.

Consequences of Introduction: 

1) Climate/Host Interaction: The plant has adapted to disturbed areas. It was first collected in 1924. Despite this early detection and its adaptation to ruderal habitats, it has not yet spread widely. It receives a Low (1) in this category.

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

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

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

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

2) 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: Snail Medic produces via numerous seeds that seem to be able to spread via gravity, and wildlife. Snail Medic 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: Snail Medic may invade croplands as a weed in certain areas. Snail Medic receives a Low (1) in this category.

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

A. The pest could lower crop yield.

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

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

D. The pest could negatively change normal cultural practices.

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

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

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

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

– Medium (2) causes 2 of these impacts.

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

5) Environmental Impact:  Snail Medic is not likely to trigger new chemical treatments by ranchers and land managers, as it is much less invasive than its congener bur-clover (Medicago polymorpha). The plant is never dominant in CA. The plant is unlikely to disrupt natural communities. Snail Medic receives a Low (1) 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 impact 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 Snail Medic: Low (8)

Add up the total score and include it here.

–Low = 5-8 points

-Medium = 9-12 points

-High = 13-15 points

6) Post Entry Distribution and Survey Information: Snail Medic has been found in in 3 counties in California, but seems to be eradicated. 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: Low (7)

Uncertainty:

Snail Medic has been in California a long time, but has spread very modestly. Although some weeds do take decades to show their true potential in an invaded area, it is not terribly likely to be true for snail medic. Therefore, uncertainty is medium to low.

Conclusion and Rating Justification:

Not a bad weed in CA and unlikely to become one. It may have a use as a small forage plant. A D rating is proposed.

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.

Florabase; Snail Medic:  http://florabase.dpaw.wa.gov.au/browse/profile/2450

USDA Plants Database. Medicago scutellata. Accessed 6/12/2015:

http://plants.usda.gov/core/profile?symbol=MESC6

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

European Frogbit | Hydrocharis morsus-ranae L.

California Pest Rating for
European Frogbit | Hydrocharis morsus-ranae L.
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.

History & Status:

European frogbit is an annual herbaceous aquatic plant native to Europe. European frog-bit is generally free-floating but in situations where the vegetation is dense enough, the leaves may become emergent. It has been found in the Great Lakes Basin since the 1930s, but is now spreading into inland streams and lakes within the larger area surrounding the Great Lakes. It is considered invasive as it can displace native flora, possibly resulting in habitat impacts on native fauna by reducing oxygen content of bodies of water. European frogbit populations increase in size rapidly by vegetative reproduction and forms dense mats. These mats can infest irrigation canals.  There are no effective controls for this species at this time. European frogbit was planted in ponds in Ottawa in 1932. It apparently escaped from these ponds; by 1939 it was found in the Rideau Canal and by 1967 it had spread into Lake Ontario, Lake Erie, and several localities in New York.

Official Control: None in California.

California Distribution:  European frogbit does not occur in California at this time.

California Interceptions: None.

This threat European frogbit 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: 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 the plant could occur in wetlands such as the Delta.

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). The plant produces via numerous seeds and overwintering turions, as well as spreading rapidly in water via vegetative growth.

4  Economic Impact: Evaluate the likely economic impacts of the pest to California using the criteria below. Score: 1

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 low (1) as the plant can impede irrigation.

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.  Significantly impacting 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 invade the water systems of California, disrupt natural lake communities and potentially lower biodiversity by covering lake surfaces.  

Consequences of Introduction to California for European frogbit:

Add up the total score and include it here. (12)

—Low = 5-8 points

—Medium = 9-12 points

—High = 13-15 points

6.  Post Entry Distribution and Survey Information: Evaluate the known distribution in California. Only official records identified by a taxonomic expert and supported by voucher specimens deposited in natural history collections should be considered. Pest incursions that have been eradicated, are under eradication, or have been delimited with no further detections should not be included.
Score: 0

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

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

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

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

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

Uncertainty:

It’s not here yet, but it is invasive in the Great Lakes Region.

Conclusion and Rating Justification:

A potentially weedy plant, especially in mountain lakes and cooler freshwater basins. Deserves an A rating, as it’s so invasive in other states.

References:

Catling P.M., Dore W.G., 1982, Status and identification of Hydrocharis morsus-ranae  and Limnobium spongia  (Hydrocharitaceae ) in northeastern North America, Rhodora 84(840): 523-545.

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

Global Invasive Species database: http://www.issg.org/database/species/ecology.asp?si=862

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

Limnobium laevigatum | South American spongeplant

California Pest Rating for
Limnobium laevigatum  |  South American spongeplant
Pest Rating: A  |  Proposed Seed Rating: P
PEST RATING PROFILE
Initiating Event:

This plant has been rated as “Q” on the CDFA Plant Pest Rating list for some years

History & Status:

South American spongeplant is a perennial herbaceous aquatic plant native to South America. South American spongeplant is generally free-floating but in situations where the vegetation is dense enough, the leaves may become emergent. It has been found on the San Joaquin River and in the Sacramento-San Joaquin Delta. Spongeplant can form thick mats across the water causing problems for boats, fish, and water infrastructure. It can spread rapidly through quick seed production and vegetative growth. The small, floating seeds easily disperse once produced. It is invasive as it can displace native flora, possibly resulting in habitat impacts on native fauna by reducing oxygen content of bodies of water. Spongeplant populations increase in size rapidly by vegetative reproduction and form dense mats. These mats can infest irrigation canals.

Official Control: An extensive control project has been carried out by the state of California.

California Distribution: South American spongeplant has been found in Alameda, Fresno, Riverside, Shasta, Fresno, Mariposa, and Humboldt Counties. It has been eradicated from some of these counties, but persists in the Delta.

California Interceptions:  Specimens have been sent to CDFA for confirmation.

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 can occur in many wetlands such as the Delta.

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). The plant produces via numerous seeds, as well as spreading rapidly in water via vegetative growth. Large rafts of plants can be redistributed by wind to new areas. South American spongeplant is occasionally available in the aquarium trade and such plants could form the nexus for new infestations if discarded or dispersed into wetlands.

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 plant can impede irrigation, boating, fishing, and swimming. It ruins views of water; and effects tourism, threatens water supplies (blocks canals, pumps, dams), and increases flooding.

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.  Significantly impacting 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 invade further water systems of California, disrupt natural lake communities and potentially lower biodiversity by covering lake surfaces.  It can block birds’ access to water and suffocate fish and other animals by sealing water surface from air. Dying plants steal oxygen in water.

 Consequences of Introduction to California for South American spongeplant: 

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: -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.

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

Uncertainty:

Known invasive in California. Minimal uncertainty.

Conclusion and Rating Justification:

A potentially terrible weed in California. Deserves an A rating as it has invaded certain areas and undoubtedly has the ability to spread much more. Because of this potential future harm, an A rating is justified.

References:

Akers, P. 2010. South American spongeplant. PDF download 3/12/2015:

http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=4&ved=0CEsQFjAD&url=http%3A%2F%2Fwww.cdfa.ca.gov%2Fphpps%2Fipc%2Fhydrilla%2Fsos%2Fsos_info%2Fsos_info.ppt&ei=ivc1U-rHAumIyAHNn4G4CA&usg=AFQjCNGI_x3yja7B_I7Hx6p8yzEwHC2l4A&sig2=iq4wwbbd_V_WhCQMTkf_8g&bvm=bv.63808443,d.aWc&cad=rja

CalIPC website. Limnobium laevigatum. Accessed 3/12/2015:

http://www.cal-ipc.org/ip/management/plant_profiles/Limnobium_laevigatum.php

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

Global Invasive Species database. Accessed 3/12/2015: http://www.issg.org/database/species/ecology.asp?si=862

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

Flowering-rush | Butomus umbellatus

California Pest Rating for
Flowering-rush | Butomus umbellatus
Pest Rating: B  |  Proposed Seed Rating: R
PEST RATING PROFILE
Initiating Event:

This plant was recently added to the Washington and Oregon noxious weed lists and it seems to be spreading.

History & Status:

Flowering rush is a perennial aquatic plant in the monotypic family, Butomaceae. First detected in North America in the 19th century along the St. Laurence River, it has spread into the Great Lake Region and begun to spread across the Northern United States and Southern Canada. Its habitat is lake shorelines and slow moving waters to a depth of around 2 meters. It is especially well adapted to the fluctuating water levels found in reservoirs, a habitat to which few other plants are adapted, but that has increased under anthropogenic conditions. Where it occurs, flowering rush densities can vary from scattered clumps to populations exceeding 50% cover. It has been documented in Idaho and Montana, but populations in Western North American are still limited. There are no infestations identified in California. The plant is spread via horticulture and water and it still is occasionally available from nurseries that sell pond plants.

California Distribution:  Flowering rush has not yet been detected in California.

California Interceptions: None.

United States Distribution: Flowering rush is distributed across the northern tier of states, including Washington.

World Distribution: This weed is native to Eurasia

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 the plant could occur in wetlands such as montane lakes, as well as irrigation canals and watering ponds in northern CA and at higher elevations.

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 can spread in water and on boats and equipment via seeds and rhizomes. It is also grown as a pond plant.

4)  Economic Impact: Evaluate the likely economic impacts of the pest to California using the criteria below. Score: 1

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 Low (1) as the plant can impede water flows in unlined canals.

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.  Significantly impacting 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 the plant could invade the water systems of California, disrupt natural wetland communities and potentially lower biodiversity by invading wetlands. This dense growth impedes water movement, blocks the growth of native plants, and reduces available habitat for water birds and native fish.

Consequences of Introduction to California for Water-primrose:

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 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: (10)

Uncertainty:

Medium. The plant has established in other states, but the extent of its adaptability to California unknown.

Conclusion and Rating Justification:

A potentially troublesome weed of wetlands, especially in northern and montane regions of California.  Deserves a B rating as it has proven weedy elsewhere, but its eventual spread in California may be limited as current infestations are in climates with cold winters.

References:

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.

Hroudová Z., A. Krahulková, P. Zákravsky, & V. Jarolimová. 1996. The Biology of Butomus umbellatus in shallow waters with fluctuating water level. Hydrobiologia 340: 1-3.

Invasive Plants of Wisconsin: Butomus umbellatus, flowering-rush, www.uwgb.edu/biodiversity/ herbarium/invasive_species/butumb01.htm

Kings County, WA Noxious Weeds. Butomus umbellatus. Accessed 3/12/2015: http://www.kingcounty.gov/environment/animalsAndPlants/noxious-weeds/weed-identification/flowering-rush.aspx

Miller, G. 2011. Oregon Risk Assessment of Butomus umbellatus. Accessed 3/12/2015: http://www.oregon.gov/ODA/shared/Documents/Publications/Weeds/PlantPestRiskAssessmentFloweringRush2013.pdf

Lavoie C., Jean M., Delisle F., Letourneau G. 2003. Exotic plant species of the St. Lawrence River wetlands: a spatial and historical analysis. Journal of Biogeography 30: 537-549

Wisconsin Department of Natural Resources – Invasive Plant Species – Flowering Rush (Butomus umbellatus). Accessed 3/12/2015: dnr.wi.gov/invasives/fact/rush_flowering.htm

USDA Plants. Butomus umbellatus. Accessed 3/12/2015: http://plants.usda.gov/java/profile?symbol=BUUM

Rice P., Dupuis V. 2008 Flowering rush: An invasive aquatic macrophyte infesting the headwaters of the Columbia River system. Northern Interior Columbia Basin Invasive Aquatic Plant Summit. 10/21/2008

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: B  |  Proposed Seed Rating: R

Posted by ls

Weeds

Jointvetch | Aeschynomene spp.

California Pest Rating for
Jointvetch | Aeschynomene spp.
Rosidae; Fabales; Fabaceae
Pest Rating: A  |  Proposed Seed Rating: P
PEST RATING PROFILE
Initiating Event:

A. rudis has been rated as “A” on the CDFA Plant Pest Rating List after being detected in a rice field in California.

History & Status:

Jointvetches are tropical emergent aquatic or terrestrial perennial, to 2 m tall that bear typical pea type flowers and jointed legume seed pods. There are about 150 species of jointvetch in subtropical and tropical areas of the world. No species are native to the Western United States, but one species (A. rudis) has been introduced. Plants are typically annual in California. Infestations were restricted to rice fields in Colusa County, California. Heavy infestations can reduce rice harvest yields, and seed is difficult to remove from rice grains during the milling process. Rough jointvetch (A. rudis) has often been misidentified as Indian jointvetch (A. indica) or northern jointvetch (A. virginica) in the Southeastern U.S. All are weeds of rice. The most common detection of these plants is as seed contaminants, but seeds are difficult to diagnose to the species level. Only a few species of jointvetch are likely to find a pathway to establishment in California (e.g., A. rudis and A. indica). Nevertheless, as these species are important rice field and wetland invaders, and species are hard to distinguish via seed, the genus is treated as a whole for purposes of risk assessment.

Official Control: May be eradicated from its one known site in California.

California Distribution:  In California, this plant is known only from a rice field in Colusa County.

California Interceptions: It has been sent to the CDFA Diagnostics Laboratory for identification and has been detected in imported seed samples.

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 the plants appeared in California and could, presumably, spread to similar habitats elsewhere in the state.

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 as a contaminant in rice seed, as well as by other means such as water and water birds.

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 plant could lower crop yield in rice, could lower crop value, trigger more treatments, and, as it can form dense stands in wet soil or shallow water, interfere with water delivery.

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.  Significantly impacting 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 disrupt wetlands. As such it could suppress native species, including rare wetland species, such as California hibiscus (Hibiscus lasiocarpus var. occidentalis) and California red-legged frog (Rana draytonii). The plant is toxic to mammals. Its presence triggers more treatments to control this weed.

Consequences of Introduction to California for Jointvetches:

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

-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:

Although zigzag jointvetch was successfully eradicated in California, the behavior of zigzag jointvetch (Aeschynomene rudis) and Indian jointvetch (Aeschynomene indica) in other areas of the world demonstrates the genus’ weedy potential in California.

Conclusion and Rating Justification:

The genus contains bad weeds of wetlands and rice fields. An A rated is justified for the genus, as the potential harm is great from introduction of any of the weedy species.

References:

Carulli, J. P. 1988. Aeschynomene rudis Benth. (Fabaceae) in the United States. Bartonia 54:18-20.


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.

Hrusa, F., B. Ertter, A. Sanders, G. Leppig, and E. Dean. 2002. Catalog of non-native vascular plants occurring spontaneously in California beyond those addressed in The Jepson Manual. Part I. Madroño 49: 61-98.

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

Egyptian Broomrape | Orobanche aegyptiaca Pers.

California Pest Rating for
Egyptian broomrape | Orobanche aegyptiaca Pers.
Lamiales: Orobanchaceae
Pest Rating: A  |  Proposed Seed Rating: P
PEST RATING PROFILE
Initiating Event:

Egyptian broomrape was found for the first time in North America in Solano County, California in July, 2014.

History & Status:

Egyptian broomrapes are annual plants that grow from seed and require a host to survive. They are a parasitic plants that grow on the roots of Broad-leaf hosts and obtain all of their nutrients and water from these plants. As such, they can seriously reduce the yield of infected crops. Seeds germinate in response to chemicals released by host plant roots. The broomrape seedling root then attaches itself to the host plant root and remains underground until flowering. The plant has no chlorophyll and no photosynthetic leaves. Flowering stems emerge about 6 weeks after germination, then flower and begin to set seed within 2–3 weeks. Seed capsules dry and shatter in summer. One plant can produce over 100,000 seeds per year and seeds may lay dormant in the soil for more many years. Broomrape seed can be spread by footwear, livestock, machinery, vehicles, flooding, as well as by contaminated fodder, seed and soil. Egyptian broomrape is a relative of branched broomrape and belongs to a species group that is among the world’s worst crop weeds. Most authorities treat Orobanche ramosa and Orobanche aegyptiaca as distinct species, and in most keys there is a clear differentiation between them on the basis of corolla length and hairiness of anthers; in practice many specimens fall on the borderline and are difficult to place with certainty. Some authorities segregate this species group of Orobanche as the genus Phelipanche, in which case the species in question is known as Phelipanche aegyptiaca Pomel. Nevertheless, as a broad approach to Orobanche is followed in the Jepson Manual and will be followed in Flora North America, the species will be recognized as Orobanche aegyptiaca here. In the wild in Europe, Egyptian broomrape attacks annual composites (members of the aster family, Asteraceae), although it occasionally attacks members of the legume family (Fabaceae) and other broad-leaved plants. Egyptian broomrape attacks a broad array of field crops and some ornamentals. Tomato, potato, tobacco, eggplant, peppers, peas, carrot, celery, mustard, spinach, and chrysanthemum are among the susceptible plants. In areas such as southern Russia melons are also potential hosts. Established broomrape infestations can reduce crop yields by up to 70%, threaten export markets, and they are extremely difficult to eradicate.

Official Control:

Egyptian broomrape has been a “Q” listed noxious weed in California since it was recently found. Although the species has not yet been given a permanent official pest designation in the United States, it is included as a federal listed noxious weed under the genus Orobanche (all species that are not native or already widespread).

California Distribution: One site in Solano County.

California Interceptions: Egyptian broomrape has been detected only in eastern Solano County, California.

United States: The finding of Egyptian broomrape in California is the first detection for North America.  

International: Egyptian broomrape is native to the Middle East and is also found as a crop weed in Eastern Europe, at least 3 countries in Africa and in the warmer parts of Asia. Before this detection in California, its only Western Hemisphere report was in Cuba.

This risk Egyptian broomrape would pose to California is evaluated below.

Consequences of Introduction: 

1)  Climate/Host Interaction: The plant has attacked crops in many countries in the Eastern Hemisphere. It is more adapted to warmer climates than its close relative branched broomrape. This makes it well adapted to the regions of California where most row crops are grown. Therefore, Egyptian broomrape scores as 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 Egyptian broomrape is documented to attack at least 23 crops grown in California. Important crops it is known to attack include tomato, olive, melons, cucumbers, eggplants, and carrot. Therefore, Egyptian broomrape scores as High (3) in this category.

Evaluate the host range of the pest. Score:

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

3)  Pest Dispersal Potential: Egyptian broomrape produces numerous seeds that seem to last for years and be able to spread via equipment and on animals (including humans). The seed bank is highly persistent. Egyptian broomrape 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: Egyptian broomrape can lower crop productivity in susceptible row crops by up to 70%. This can make profitable crops unprofitable, affect land value, and result in quarantine. Furthermore, the weed may also be present on broadleaf weeds in fields when non-host crops are grown, affecting marketability of additional crops due to potential seed contamination. Egyptian broomrape 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: Egyptian broomrape is likely to trigger new treatments by land managers. The plant has not yet spread to the wild in California. However, certain native plants such as our annual composites (Asteraceae) and legumes such as clovers (Trifolium) are likely susceptible to attack from Egyptian broomrape. These include such rare or endangered species such as Contra Costa goldfields (Lasthenia conjugens), Suisun aster (Symphyotrichum lentum), Delta tule pea (Lathyrus jepsonii jepsonii), and showy Indian clover (T. amoenum).   Egyptian broomrape 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. 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 Branched broomrape: 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: Egyptian broomrape  has been found in 1 county in California, and may be eradicable. 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 (14)

Uncertainty:

The experience in the Middle East shows the potential of this species to disrupt crop systems. Its potential effects on the environment are more speculative and necessarily more uncertain.

Conclusion and Rating Justification:

Egyptian broomrape is a bad agricultural weed because of its ability to reduce yields, produce large numbers of long-lived seeds, and its ease of spread. Therefore, its advent into California can be viewed as a significant event in North American agriculture. It should be included in regulations such as the California Code of Regulations Section 4500 list of noxious weeds as it is already included on the USDA noxious weed list.

References:

Blanco G. & M. Cueto. 2011. Orobanche 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.

CABI. Invasive Species Compendium:  Orobanche aegyptiaca. Accessed online 7/21/2014: http://www.cabi.org/isc/datasheet/37742

Carlón, L. G. Gómez Casares, M. Laínz, G. Moreno Moral, Ó. Sánchez Pedraja, & G. M. Schneeweiss. Annotated Checklist of Host Plants of Orobanchaceae: Accessed 7/10/2014: http://www.farmalierganes.com/Flora/Angiospermae/Orobanchaceae/Host_Orobanchaceae_Checklist.htm#L_Host

Chater, A. O. & D. A. Webb. 1971. Orobanche in Flora Europaea Vol. 3: Diapensiaceae to Myoporaceae. T. G. Tutin, V. H. Heywood, N. A. Burges, D. H. Valentine, S. M. Walters, & D. A. Webb, eds. Cambridge University Press. United Kingdom.

Grupo Botánico Cantábrica. Index of Orobancheaceae: Phelipanche aegyptiaca.  Accessed online 7/16/2014: http://www.farmalierganes.com/flora/angiospermae/orobanchaceae/phelipanche/Phelipanche_aegyptiaca/Phelipanche_aegyptiaca.htm

Kasasian, L. 1971. Orobanche spp. PANS Pest articles and News Summaries 17: 1.

USDA Plants Database, Orobanche ramosa. Accessed 7/16/2014: http://plants.usda.gov/core/profile?symbol=orra

Jacobsohn, R., A. Greenberger, J. Katan, M. Levi & H. Alon. 1980. Control of Egyptian Broomrape (Orobanche aegyptiaca) and Other Weeds by Means of Solar Heating of the Soil by Polyethylene Mulching. Weed Science 28: 312–316
.

http://www.infonet-biovision.org/default/ct/705/pests

Eizenberg, H., T. Lande, G. Achdari, A. Roichman & J. Hershenhorn. Effect of Egyptian Broomrape (Orobanche aegyptiaca) Seed-burial depth on parasitism dynamics and chemical control in tomato. 2007. Weed Science 55: 152–156
.

Sedigheh S, R. Aptin, & Y. A. Zoheir. 2009. Application soil solarization on the control of Egyptian broomrape in greenhouse. International Journal of Natural and Engineering Sciences 3: 59-64.

Ghannam, I., R. Barakat, & M. Al-Masri. 2007. Biological control of Egyptian broomrape (Orobanche aegyptiaca) using Fusarium spp. Phytopathologia Mediterranea [Online], 46.2: 177-184.

Web. 24 Oct. 2012
6. http://www.flowersinisrael.com/Orobancheaegyptiaca_page.htm

Eizenberg, H, Y. Goldwasser, S. Golan, D. Plakhine, & J. Hershenhorn. 2004. Egyptian broomrape (Orobanche aegyptiaca) Control in tomato with sulfonylurea herbicides—greenhouse studies. Weed Technology 18: 490–496.

Eizenberg, H., D. Plakhine, J. Hershenhorn, Y. Kleifeld, and B. Rubin. Resistance to broomrape (Orobanche spp.) in sunflower (Helianthus annuus L.) Is Temperature Dependent. Journal of Experimental Botany 54: 1305-311.

Hamamouch, N. 2004. Engineering resistance to Orobanche aegyptiaca: evidence of sarcotoxin IA as an anti-parasite protein and macromolecule movement from host to parasite. Diss. Virginia Polytechnic Institute and State University.

Joel, D. M., J. Hershenhorn, H. Eizenberg, R. Aly, G. Ejeta, P. J. Rich, J. K. Ransom, J. Sauerborn, & D. Rubiales. 2007. Biology and management of weedy root parasites. Horticultural Reviews 33: 267-350.

Fernandez-Aparicio, M. Sillero, J. C. Rubiales, D. 2009. Resistance to broomrape species (Orobanche spp.) in common vetch (Vicia sativa L.). Crop Protection 28: 7-12.

Doronina, A. Y. Orobanche aegyptiaca. Interactive agricultural Ecological Atlas of Russia and Neighboring Countries. Accessed July, 2014. http://www.agroatlas.ru/en/content/weeds/Orobanche_aegyptiaca/

Hershenhorn J,, H. Eizenberg, E. Dor, Y. Kapulnik, & Y. Goldwasser. 2009. Phelipanche aegyptiaca management in tomato. Weed Research 49:34–37.

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

Goatsrue (Galega officinalis)

California Pest Rating for
Goatsrue (Galega officinalis)
Pest Rating: A  |  Seed Rating: P
PEST RATING PROFILE
Initiating Event:

There is a recent detection of goatsrue found growing in Eastern Mendocino County. This is the first detection of this species occurring spontaneously in California.

History & Status:

Background: Goatsrue is a deep-rooted perennial, sprouting each spring from a crown and taproot reaching 2 to 6 feet tall by late summer. Plants may have up to 20 hollow stems. The first seedling leaves are large, oval and dark green. The mature leaves are alternate, odd-pinnate with six to ten pairs of leaflets. The white and bluish to purplish pea-like blossoms are borne in terminal or axially racemes. A single plant may produce upwards of 15,000 pods. Goatsrue seeds drop on the ground when mature and may be spread by water, equipment, or animals. Goatsrue seeds typically remain dormant until scarified and may remain viable for ten or more years.
Goatsrue is a USDA federally listed noxious weed. A member of the legume family, goatsrue was introduced into Utah in 1891 as a potential forage crop. Goatsrue now occupies in excess of 60 square miles in Cache, County, Utah. Within this area, goatsrue infests cropland, fence lines, pastures, roadsides, waterways, and wet, marshy areas. The plant’s stems and leaves contain a poisonous alkaloid, galegin, which renders the plant unpalatable to livestock, and toxic in large quantities. It is particularly lethal to sheep.
Goatsrue is controlled by herbicides such as 2,4-D plus Dicamba or glyphosate, although the crowns of treated plants may remain viable up to seven years unless retreated or removed. New herbicide chemistry may improve success rates. Tillage in row crops can suppress regrowth and break up the seed production cycle. Utah weed control personnel indicate that goats rue control is very difficult, requiring significant amounts of time and labor. Their experience reinforces the concept that early detection and rapid control is the most effective means of preventing large-scale establishment.

Official Control: Goatsrue is listed as a noxious weed in Alabama, Florida, Massachusetts, Minnesota,Nevada, North Carolina, Oregon, Pennsylvania, South Carolina, Vermont, and Washington.

Worldwide Distribution: Goatsrue is native to the Middle East; it viewed as naturalized throughout most of Europe, western Asia, and western Pakistan.

U.S. Distribution: In the U.S. goatsrue is found in 12 states, including CA, OR, WA, UT, & CO. The largest infestations occur in Cache County, Utah, where it was first introduced to the U.S. Populations in states other than CA and UT may be historic.
California Distribution: Currently, Goatsrue is known from Cow Mountain in Eastern Mendocino and Western Lake Counties.

The risk goatsrue 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: 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 localized range of the plant in states where it occurs. Goatsrue would be expected to colonize riparian areas, pond margins, wetlands, roadside ditches, irrigation canal banks, and moist forest edges.

2)  Pest Host Range: 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

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

3)  Pest Dispersal Potential: Score: 3

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.

Risk is High (3) as the plant spreads via water flow and human dispersal from vehicles. It also has ben detected as a seed contaminant in commercial seed lots.

4)  Economic Impact: Score: 3

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

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

– 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 goatsrue lowers range value and productivity and requires expensive treatments to control. As goatsrue is a federal noxious weed, there is a chance that goatsrue would trigger limitation of interstate shipment of hay or other crops from where it occurs.

5)  Environmental Impact:

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

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: 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) in California, as goatsrue is an aggressive invader of marginal wetlands. As such, it displaces native plant species in these important habitats. Species outcompeted and excluded potentially include such state and federal endangered plants as white sedge, Thomkin’s sedge, Delta eryngo, Bogg’s Lake hedge hyssop, western lily, Gambell’s watercress, and Calistoga popcornflower. Potential effects on endangered wildlife include breeding habitat modification, and food disruption (either directly from food plant exclusion, or indirectly via insect prey reduction). Potentially affected species include the Point Arena mountain beaver, red-legged frog, yellow-legged frog, and California tiger salamander.

Consequences of Introduction to California for Goatsrue:
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 distribution in California: High (14).

6)  Post Entry Distribution and Survey Information: Goatsrue has been found in in 1 locality in California; This may have spread from seed spread via a vehicle and/or cultivation. It receives a Low (-1) in this category.

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

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

Final Score:

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

Uncertainty:

This plant has just entered California, but it is spreading quickly via riparian corridors. It is not known how far its spread will extend, but the uncertainty is low that it will be invasive. Riparian habitat represents a small percentage of habitat in California, but it is widespread throughout the state and is disproportionally important due to its high water availability and high woody plant cover.

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. This justifies an “A” rating. As the plant is limited to one small areas, as far as is known, prompt and effective action would have a significant effect on the future impacts of this species.

Literature

Evans, J. O. & M. L. Ashcroft 1982. Goatsrue. Utah Agr. Exp. Stat. Res. Report.

Barrett, R. 2013. Oregon Department of Agriculture Plant Pest Risk Assessment for Goatsrue, Galega officinalis. Accessed 6/12/2015: http://www.oregon.gov/ODA/shared/Documents/Publications/Weeds/PlantPestRiskAssessmentGoatsrue2013.pdf

Oldham, M, C. V. Ransom, M. H. Ralphs, and D. R. Gardner. 2011.
Galegine Content in Goatsrue (Galega officinalis) Varies by Plant Part and Phenological Growth Stage. Weed Science 59: 349-352.

USDA Plants, Galega officinalis. Acessed 6/12/2015:
http://plants.usda.gov/core/profile?symbol=GAOF

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

Tree Spurge | Euphorbia dendroides

California Pest Rating for
Tree Spurge  |  Euphorbia dendroides
Pest Rating: B  |  Proposed Seed Rating: R
PEST RATING PROFILE
 Initiating Event:

Collection in Santa Barbara County.

History & Status:

Background: Tree spurge is a small shrub (to 2 meters) native the Mediterranean Region. It is a semi-succulent plant with ascending candelabra-like branches and elliptical leaves without a petiole about 17 mm long. The flowers (cyathia) are borne in spring. The floral bracts are bright greenish yellow. Like all true spurges, the branches and leaves exude an irritating white latex when damaged. Although it most likely arrived in CA as a garden plant, it is no longer available in the trade (except rarely as seed). Its distribution is limited by cold, as it is intolerant of frost.

Worldwide Distribution: California Distribution: Tree spurge is currently restricted to Southern Santa Barbara County, Ventura County, and the foothill region between Altadena and Pasadena in Los Angeles County.

United States: There are no naturalized populations of tree spurge outside of CA in the United States.

International: Tree spurge  is native to the Mediteranean Region where it is found in Southern Europe and Northern Africa. It is naturalized in southwestern Australia.

This risk tree spurge will pose to California is evaluated below.

Consequences of Introduction:  3

1)  Climate/Host Interaction: 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

Risk is high (3), as the plant is naturalized in more than 8 localities throughout CA.

2)  Pest Host Range:  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

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

3)  Pest Dispersal Potential:  2

Evaluate the dispersal potential of the pest:

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

Risk is Medium (2). The plant reproduces via rather large seeds that are thrown some distance from the mother plant. Nevertheless, its ability to disperse seems limited, as populations do not spread rapidly.

 4)  Economic Impact:  1

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

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

– 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 low (1) as tree spurge will be restricted to forest edges, coastal scrub, and arroyos.

5) Environmental Impact:  3

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

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

Risk is High (3). In California, tree spurge has disrupted natural sagebrush scrub communities, has triggered additional treatment programs to control it, and crowds out native species that coexist with or foster rare species.

Consequences of Introduction to California for tree spurge:

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: 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: -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:

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

Uncertainty:

There is no uncertainty as to whether this plant can establish in CA.

Conclusion and Rating Justification:

Conclusions of the harm(s) associated with this pest to California using all of the evidence presented above: Proposed Rating: Based on the score listed above the pest is a medium risk. Given its ability to spread much more widely and ongoing control efforts, a B rating would be justifed.

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/). 2014.

Global Compendium of Weeds: http://www.hear.org/gcw/species/euphorbia_dendroides/

Jepson Flora Project (eds.) 2013. Jepson eFlora, http://ucjeps.berkeley.edu/IJM.html, accessed on Mar 28 2014

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: B  |  Proposed Seed Rating: R

Posted by ls