All posts by Dean Kelch

Laportea canadensis


Canadian wood-nettle (Laportea canadensis), photographed at Brooklyn Botanic Garden (New York) in September
Canadian wood-nettle (Laportea canadensis), photographed at Brooklyn Botanic Garden (New York) in September. Photo By: Raffi Kojian (http://Gardenology.org) [CC BY-SA 3.0], via Wikimedia Commons
California Pest Rating
Laportea canadensis
Former Pest Rating:  Q
CURRENT Pest Rating: D | Proposed Seed Rating: N/A
Initiating Event:

This plant has been rated as “Q” by the CDFA Botany Lab in response to a border detection.

History & Status:

Wood nettle is a common perennial herb native to eastern North America, where it is found growing in moist to wet soil in the understory of Eastern Deciduous Forests. It has a strong family resemblance to the common nettle (Urtica dioica), but unlike most other members of the nettle family, it has alternate leaves. These leaves are broadly heart-shaped with a toothed margin. The plant is sparsely covered by stinging hairs. The effect of touching it is similar to touching common nettles, but not as severe. Native Americans used wood nettle to treat incontinence and tuberculosis, to counteract poison, as a love medicine, and to facilitate childbirth.

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

California Distribution:  None.

California Interceptions:  A new interception was made in Yolo County on 6/14/2017 (PDR NE0P06655513).

Consequences of Introduction: 

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

Risk is Low (1), as the preferred habitat of wood nettle (moist, dense, deciduous forest) does not occur in California. Score: 1

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

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

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

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

Low (1) has a very limited host range.

Medium (2) has a moderate host range.

High (3) has a wide host range.

3) Pest Dispersal Potential: Evaluate the natural and artificial dispersal potential of the pest. Risk is Medium (2). The plant produces numerous seeds that are apparently able to spread via water distribution. Patches may be the result of root sprouting. 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.

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

Economic Impact: 

A. The pest could lower crop yield.

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

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

D. The pest could negatively change normal cultural practices.

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

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

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

Economic Impact Score: Risk is Low (1). No economic impact, even where it is common in Eastern North America.

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

Environmental Impact:

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

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

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

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

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

Environmental Impact Score:  Low (1).  The plant is well integrated into its native landscape, and is not known to be weedy. It is unlikely to be adapted to any part of California.

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 wood nettle:

Add up the total score and include it here. (8)

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. (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: (8)

Uncertainty:

Wood nettle is poorly adapted to California and it is not known to be weedy elsewhere; there is low uncertainty.

Conclusion and Rating Justification:

An Eastern woodland native. A D rating is recommended.

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.

Moerman, Daniel E. 1986. Medicinal plants of native America. Museum of Anthropology, University of Michigan, Ann Arbor.


Responsible Party:

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


Comment Period: CLOSED

45-day comment period: 7/18/17 – 9/1/17


NOTE:

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


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

Branched Broomrape | Orobanche ramosa

Branched broomrape | Orobanche ramosa (Photo by CDFA)California Pest Rating
Orobanche ramosa L., branched broomrape
Lamiales; Orobanchaceae
Former Pest Rating:  A
CURRENT Pest Rating: A |  Proposed Seed Rating: P 
Initiating Event:

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

History & Status:

Branched broomrapes are annual plants that grow from seed and require a plant host to survive. It is a parasitic plant that grows on the roots of Broad-leaf hosts and obtains all of its nutrients and water from these plants. 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 noticeable leaves. Flowering stems emerge from the ground about 6 weeks after germination; flowering and seed set occur within 2–3 weeks. Seed capsules dry and shatter in summer. One plant can produce over 100,000 seeds and seeds may lay dormant in the soil for more than 40 years. Broomrape seed can be spread by livestock, machinery, vehicles, flooding, and contaminated fodder, seed and soil. Branched broomrape is among the world’s worst crop weeds and poses a serious threat to the vegetable industry in California. It has been reported to attack 25 different crops including lettuce, tobacco, and tomatoes. Once established, branched broomrape can reduce crop yields by up to 70% and it is extremely difficult to eradicate. For this reason, it is often regulated and trading partners that import fresh host material may limit or exclude trade in these commodities.

Official Control: Branched broomrape has been an “A” listed noxious weed in California for many years. There was a state control and eradication program in California for branched broomrape that lasted over 20 years; it was discontinued in the late 1970s. It is also a federally listed noxious weed and is listed as noxious in Alabama, Arizona, Florida, Massachusetts, Minnesota, North Carolina, Oregon, South Carolina, Texas, and Vermont.

California DistributionBranched broomrape was known from about a dozen infestations of agricultural fields in Central and Southern California. Most of these sites have been developed over the years and therefore the plant is likely eradicated at these sites (there have been no detections in over 30 years). A known extant infestation is in northern San Benito County; this population reappeared after more than 30 years, when the field was planted to tomatoes.  A second occurrence was found in 2014 in San Joaquin County, in an area near known infestations from the 1970s.

California Interceptions: Vouchered specimens are known from Sacramento, Alameda, San Benito, San Joaquin, Santa Clara, and Ventura Counties.

United States: Branched broomrape has been found in California, Illinois, Kentucky, North Carolina, New Jersey, and Texas.

International: Branched broomrape is native to the Mediterranean. It is reported as naturalized and as an environmental and agricultural weed in Europe and western Asia. It has also been detected in Australia where they are transitioning from attempted eradication efforts to ongoing management.

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

Consequences of Introduction: 

1) Climate/Host Interaction: The plant has attacked crops in many countries spanning many climates. It is highly variable and this variation seems to be tied to differential ecological preferences. Therefore, It 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 branched broomrape attacks 25 crop species and probably has the potential to attack many native species as well.

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: Branched broomrape produces numerous seeds are documented to last for decades and are able to spread via equipment and on animals (including humans). The seed bank is highly persistent. Branched 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:  Evaluate the economic impact of the pest to California using the criteria below.

Economic Impact: A, B, C, D

A. The pest could lower crop yield.

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

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

D. The pest could negatively change normal cultural practices.

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

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

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

Economic Impact Score: Branched broomrape receives a High (3) in this category.  Branched broomrape can lower crop productivity in susceptible row crops by up to 70%. This can affect land value and result in quarantine.  

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

Environmental Impact: A, B, D

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

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

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

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

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

Score the pest for Environmental Impact.

Environmental Impact Score: Branched broomrape receives a High (3) in this category. Branched 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 clovers (Trifolium) are likely susceptible to branched broomrape. These include such rare or endangered species as showy Indian clover (T. amoenum), Buck’s clover (T. buckwestiorum), and Monterey clover (Trifolium trichocalyx).   

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: Branched broomrape has been recently found in three counties in California, but may be eradicated. 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: High (13)

Uncertainty:

The experience in the mid 20th century of California and in Australia show the potential of this species to disrupt crop systems. Its effects on the environment are more speculative and necessarily more uncertain.

Conclusion and Rating Justification:

A terrible agricultural weed because of its ability to produce large numbers of long-lived seeds and its ease of spread. It deserves an A rating as it is likely to have a high impact if it spreads again in California. Development has removed most known sites, but it is otherwise difficult to treat.

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/

Cooke, D. 2002. Control of branched broomrape; a literature review. Animal and Plant Control Commission of South Australia.

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

NSW Department of Primary Industries. Weed alert; branched broomrape: http://www.dpi.nsw.gov.au/agriculture/pests-weeds/weeds/profiles/broomrapes

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


Responsible Party:

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


Comment Period: CLOSED

45-day comment period: 7/18/17 – 9/1/17


NOTE:

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


Pest Rating: A |  Proposed Seed Rating: P

Myrtle Spurge | Euphorbia myrsinites


California Plant Pest Rating
Myrtle Spurge (Euphorbia myrsinites)
Former Pest Rating:  Q
CURRENT Pest Rating: A  |  Proposed Seed Rating: R
Initiating Event:

Collection in Lassen County by county staff and submission to the CDFA Botany Lab.

History & Status:

Background: Myrtle spurge is a deciduous, perennial herb (to 10 cm tall by 40 cm wide) native to southeastern Europe through Asia Minor. It is a semi-succulent plant with prostrate branches and awl-shaped, blue leaves without a petiole approximately 2 cm 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. It arrived in CA as a garden plant, and it can be found at nurseries in the north and at higher elevations. It’s is extremely cold hardy, but evidently doesn’t thrive in areas with severe summer drought.

California Distribution: Myrtle spurge is currently restricted in California. There are 2 small populations, persisting but not spreading, known along the coast in Alameda and Ventura Counties. It was once collected in Kern County. A small population in Quincy, Plumas County has evidently been eradicated. The recent find, in Lassen County, is reportedly spreading from nearby cultivation. A similar case exists east of Macarthur, Shasta County.

United States: Myrtle spurge is highly invasive in Utah and other western, interior states including Wyoming, Colorado, Eastern Oregon, Washington and New Mexico. It has also been collected as waif in a few eastern states such as Wisconsin and Virginia.

International: Myrtle spurge is native to southeastern Europe through Asia Minor.

Regulation: Myrtle spurge is listed as a noxious weed in Colorado, Oregon, Washington and Utah.

This risk Myrtle spurge will 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. Risk is Medium (2), as the plant could naturalize throughout higher elevation mountains and in the “sagebrush” area of northeastern California.

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

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

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

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

Evaluate the host range of the pest: 3

– Low (1) has a very limited host range

– Medium (2) has a moderate host range

High (3) has a wide host range

3) Pest Dispersal Potential:  Risk is Medium (2). The plant reproduces via numerous, 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. It is unlikely to be found in commercial crop seed.

Evaluate the dispersal potential of the pest:

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

Medium (2) has either high reproductive or dispersal potential

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

4) Economic Impact: Risk is High (3) as Myrtle spurge, where established, lowers the rangeland productivity, is unpalatable to livestock, and, where common, will necessitate herbicide treatments for control. As it is a noxious weed in several western states, infested commodities could be excluded from those states that list it as noxious.

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

Economic Impact: A, C, D

A. The pest could lower crop yield

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

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

D. The pest could negatively change normal production cultural practices

Economic Impact Score: 3

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

-Medium (2) causes 2 of these impacts

High (3) causes 3 or more of these impacts

5) Environmental Impact:  Risk is High (3). In California, Myrtle spurge could disrupt natural bunchgrass and sagebrush scrub communities. Once established, it would trigger additional treatment programs to control it, as in Utah. It would crowd out native species that coexist with or foster rare species.

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

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

Environmental Impact: B, C, D

A. The pest could directly affect threatened or endangered species

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

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

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

Environmental Impact Score: 3

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

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

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

Consequences of Introduction to California for Myrtle 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: High (13).

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:

Because there is ample evidence of its invasiveness in Utah, Oregon and Colorado, there is little uncertainty that this plant can establish and become invasive in similar climatic areas of California.

Conclusion and Rating Justification:

Conclusions of the harm(s) associated with this pest to California using all of the evidence presented above: Proposed Rating: Based on the score listed above the pest is a High risk. It has the ability to spread more widely in California. Its current limited distribution in California makes the feasibility of eradication high. An A rating is 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 (cjeps.berkeley.edu/consortium/). 2014.

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

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

Washington State Weed Control Board; Myrtle Spurge. Accessed 6/18/2017: http://www.nwcb.wa.gov/weeds/myrtle-spurge


Responsible Party:

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


Comment Period: CLOSED

45-day comment period:  7/17/17 – 8/31/17


NOTE:

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


Pest Rating: A  |  Proposed Seed Rating: R

 

Sahara Mustard | Brassica tournefortii

California Pest Rating
Brassica tournefortii Gouan. | Sahara mustard
Former Pest Rating:  Q
CURRENT Pest Rating: C | Proposed Seed Rating: R
Initiating Event:

This plant has been rated as “Q” by CDFA botany staff.

History & Status:

The genus Brassica comprises about 40 species and many agricultural cultivars such as cabbage, mustard, bok choi, brussel sprouts, canola, broccoli, turnip, etc. Sahara mustard, as the name implies, is a species adapted to dry, sandy soils.

Sahara mustard forms a basal rosette like most mustards from which grows a highly branched inflorescence with hundreds of typical mustard 4-parted yellow flowers. The basal leaves generally have more than a dozen pairs of lobes or leaflets; this is more than is typical for most other Brassica spp. As the plant fruits, it dies. The dense tangle of stems and fruits breaks off at ground level and tumbles over the ground in windy situations, releasing seeds as it moves through the landscape. The seeds sometimes occur as a contaminant in agricultural seed lots and they are easily distinguishable from other mustard seeds.

Official Control: Some land managers control this plant, but where it is adapted it is generally too common to control it well.

California Distribution:  Sahara mustard is known from at least 15 counties in California; most are in the southern California. It is very common in warm desert regions.

California Interceptions: Sahara mustard was first collected in California in the 1920s from the Coachilla Valley. From that region, it has spread widely to surrounding areas.

United States: Sahara mustard is known from California, Texas, New Mexico, Arizona, and Nevada in the United States.

International:  Sahara mustard occurs in all of North Africa from Morocco through Egypt, in southern Europe, and through Western Asia. It is an introduced weed in Australia.

Consequences of Introduction: 

1) Climate/Host Interaction:  Risk is Mediium (2), as the plant is naturalized on roadsides in the desert and then moves into open desert from these areas. More recent finds in coastal California indicates that it may invade southern coastal areas as well.

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

Score: 2

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

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

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

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

Evaluate the host range of the pest.

Score: 3

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

-Medium (2) has a moderate host range.

-High (3) has a wide host range.

3) Pest Dispersal Potential:  Risk is Medium (2). The plant produces a large number of seeds that spread along roads. It then spreads into the desert interior via the “tumbleweed” inflorescences. It is especially good at exploiting sandy soils.

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.

4) Economic Impact: The presence of this plant in the Anza Borrego desert impacts the spring wildflower tourist industry, as the plant outcompetes native wildflowers that form the basis of an important tourist industry. If it infests row crops or irrigated areas, it lowers crop value or crop yield.

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

Economic Impact: A, B, C, F

A. The pest could lower crop yield.

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

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

D. The pest could negatively change normal cultural practices.

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

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

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

Economic Impact Score: 3

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

-Medium (2) causes 2 of these impacts.

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

5) Environmental Impact: Risk is High (3) as the plant is able to dominate desert areas that are home to sensitive species such as desert tortoise, blunt-nosed leopard lizard, and many rare native plants.

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

Environmental Impact:  A, C, D

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

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

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

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

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

Environmental Impact Score: 3

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

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

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

Consequences of Introduction to California for Sahara mustard: High (13)

Add up the total score and include it here.

Low = 5-8 points

Medium = 9-12 points

High = 13-15 points

6) Post Entry Distribution and Survey Information: Sahara mustard has been found in many counties in California, most commonly in the south. It has spread widely during the last 20 years in California. It receives a High (-3) in this category.

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

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

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

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

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

Final Score:

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

Uncertainty:

Given that populations of Sahara mustard have exploded in the last 20 years, uncertainty is low. It only remains to be seen how well it can invade the Mediterranean coastal and central regions of California. The likelihood is that it has fully invaded the areas where it is best adapted and newer incursions will occur, but that they will prove to be limited.

Conclusion and Rating Justification:

Although Sahara mustard may be somewhat limited in its spread by its environmental preferences, it has shown itself quite invasive where it is adapted. Because it is so widespread, especially in the desert areas, it should be given a C rating.

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.

Berry, K. H., T. A. Gowan, D.M. Miller & M. L. Brooks. 2014. Models of Invasion and Establishment for African Mustard (Brassica tournefortii). Invasive Plant Science and Management 7: 599-616.

Bhagirath S. Chauhan, Gurjeet Gill, and Christopher Preston (2006) African mustard (Brassica tournefortii ) germination in southern Australia. Weed Science: September 2006, Vol. 54, No. 5, pp. 891-897.

Cal_IPC website. Sahara mustard (Brassica tournefortii) research. Accessed 12/17/2015: http://www.cal-ipc.org/ip/research/saharan/index.php

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

Malusa, J., B. Halvorson, and D. Angell. 2003. Distribution of the exotic mustard Brassica tournefortii in the Mohawk Dunes and Mountains, Arizona. Desert Plants 19:31–36.

Sanders, A., & R. Minnich. 2000. Brassica tournefortii. in Bossard, C. C., J. M. Randall, and M. M. Hochovsky. Invasive Plants of California’s Wildlands. University of California Press, Berkeley, CA.


Responsible Party:

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


Comment Period: CLOSED

45-day comment period: July 14, 2017 – August 28, 2017


NOTE:

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


Pest Rating: C | Proposed Seed Rating: R

Hedera spp. (English Ivy, Irish Ivy & Algerian Ivy)

California Pest Rating
Hedera spp.  (English Ivy, Irish Ivy & Algerian Ivy)
Former Rating:  None
CURRENT Pest Rating: None |  Proposed Seed Rating: None
Initiating Event:

This plant is subject to a petition to the Secretary to list English ivy (Hedera helix) as a noxious weed.

History & Status:

True ivies (Hedera spp.) are vining, evergreen plants with dark, glossy, (generally) lobed leaves. When they reach something to climb on, they grow upwards using innumerable adventitious roots that sprout from the stems. After growing upward into sun, the plant changes it growth form, producing unlobed leaves and rigid stems that project from the framework. These fertile stems produce many small green flowers in compound umbels. The fruits are black berries (yellow in H. helix subsp. poetarum) that are generally dispersed by birds, sometimes to a great distance from the mother plant. Although a single ivy plant can carpet a ~0.1 hectare area or take over a tree, it is the bird-dispersed seed that account for most of the continuous spread of the plants.

The various species of ivy are difficult to distinguish and they sometimes hybridize. Even in their home range, widespread cultivation of non-native species or cultivars make identification difficult. The most common species in cultivation on the West Coast are English ivy (H. helix), Irish ivy (H. hibernica) and Algerian ivy (H. algeriensis, synonym H. canariensis). They can be distinguished by the types of hairs on the underside of the leaves, as well as by their chromosome number. Nevertheless, because of confusion between the species, all three will be treated together.

Ivies are popular ground covers in gardens, where they can dominate large areas with a weed resistant mat. Many cultivars have been developed over the years and some gardeners form collections of the various forms. As pot plants, they are often trained over frameworks into topiaries.

Worldwide Distribution: Ivies are widespread throughout Eurasia, northern Africa and the Canary Islands (Hedera algeriana). As adventives, ivies are widespread in forested temperate and warm temperate areas of the world. In the United States, ivies have been found as introductions in all western, all eastern and all southern states.

Official Control: Ivies are listed as official weeds in Oregon and Washington. In California, some State Parks and other land management agencies have instituted ivy control in lands under their jurisdiction.

California Distribution:  Aside from frequent usage in gardens, ivies are adventive in much of the state in the understory of forests. Ivies are only lacking in the hotter, drier areas.

California Interceptions:  Ivies have been collected over 350 times in California, although many of these collections represent plants persisting from cultivation.

The risk ivies 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.

Risk is High (3) as the plant is naturalized in many localities in CA. It prefers the north where there are extensive forests and higher rainfall, but ivies have proved themselves capable of spreading under favorable conditions (e.g., along rivers and creeks) in many areas of California. In Washington, Irish ivy is more invasive than English ivy and much more invasive than Algerian ivy. However, this relationship may differ in other parts of the West Coast. English ivy may be more invasive in California.

Score: 3

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

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

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

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

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

Score: 3

Low (1) has a very limited host range.

Medium (2) has a moderate host range.

High (3) has a wide host range.

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

Risk is Medium (2). The plants produce large vines that can dominate significant areas. Mature plants can form thousands of bird-dispersed seeds per year.

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.

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

Risk is Medium (2) as the plants can lower timber crop value by interfering with tree seedling establishment, damage adult trees by overgrowing them and poison livestock if grazed extensively.

Economic Impact 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.

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

Risk is High (3) as the plant can dominate forest understories and forest margins, excluding native plants and lowering biodiversity, and can exclude cultural plants from a landscape. They can also affect threatened or endangered species by overgrowing their food plants, e.g., covering rocky slopes supporting the host plant of the San Bruno elfin butterfly (Callophrys mossii bayensis).

Environmental Impact. Score: 3

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.

– 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 true ivies:

Add up the total score and include it here. High (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. (-3)

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

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

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

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

Final Score:

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

Uncertainty:

The dry climate has limited ivies’ spread in CA. However, they are still spreading in shady forest and riparian habitats, as they are in OR & WA.

Conclusion and Rating Justification:

These are very bad forest weeds. The magnitude of their planted and escaped populations preclude regional control and ensure their continued widespread distribution. Currently, classifying true ivies as noxious weeds would not significantly impact its current or future distribution, as they would continue to spread despite regulation. Many birds feed on ivy berries and can travel long distances from existing residential and naturalized sources.

Similar invasive and widespread plants have been given a C rating. Only a small number of noxious weeds are C rated weeds; However, the California Food and Agriculture Code section 5004 states that “In determining whether or not a species shall be designated a noxious weed for the purposes of protecting silviculture or important native plant species, the director shall not make that designation if the designation will be detrimental to agriculture.” As ivies are largely weeds of forest areas and are mainstays of the nursery agricultural sector, they would fall under this stricture.

Classifying Hedera spp. as noxious weeds would harm agriculture by preventing the sale of popular nursery plants. At this point in their invasion curve, newly planted ivies represent a very small contribution to the existing populations. Any regulation of this plant would have little or no consequence in limiting its invasiveness or reducing the costs of ivy management. Therefore, given the economic and horticultural importance, no rating is recommended for English ivy, Irish ivy and Algerian ivy at this time.

References:

Ackerfield J. & J. Wen. 2002. A morpholometric analysis of Hedera L. and its taxonomic implications. Adansonia 24:197–212.

Aizpuru I., C. Aseguinolaza, P. M. Uribe-Echebarría, P. Urrutia, e I. Zorrakín. 2003. Claves ilustradas de la flora del País Vasco y Territorios Limítrofes. Eusko Jaurlarizaren. Vitoria-Gasteiz, Spain.

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, CA.xw

Bramwell, D & Z. Bramwell. 1994. Flores Silvestres de las Islas Canarias. Editorial Rueda. Madrid, Spain.

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

King County: English Ivy, Hedera helix. Accessed 2/15/2017. http://www.kingcounty.gov/services/environment/animals-and-plants/noxious-weeds/weed-identification/english-ivy.aspx

Midori M. C., S. H. Reichard, & C. W. Hamilton. 2006. Prevalence of different horticultural taxa of ivy (Hedera spp., Araliaceae) in invading populations. Biol. Invasions 8:149-157.

USDA Plants; Hedera helix. Accessed 2/15/2017:  https://plants.usda.gov/core/profile?symbol=HEHE

Vargas P., H. A. McAllister, C. Morton, S. L. Jury & M. J. Wilkinson. 1999.  Polyploid speciation in Hedera (Araliaceae): phylogenetic and biogeographic insights based on chromosome counts and ITS sequences. Plant Systematics and Evolution 219:165–179.

Webb, D. A. 1968. Hedera in Flora Europaea Vol. 2: Rosaceae to Umbelliferae. T. G. Tutin, V. H. Heywood, N. A. Burges, D. H. Valentine, S. M. Walters, & D. A. Webb, eds. Cambridge University Press. United Kingdom.

Responsible Party:

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


Comment Period: CLOSED

45-day comment period: Feb 22, 2017 – April 8, 2017


Pest Rating: None |  Proposed Seed Rating: None

 

Dittrichia viscosa (L.) Greuter: false yellowhead

California Pest Rating
Dittrichia viscosa (L.) Greuter: false yellowhead
Asteridae: Asteraceae
Former Pest Rating:  Q
CURRENT Pest Rating: A  |   Proposed Seed Rating: P
Initiating Event:

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

History & Status:

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

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

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

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

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

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

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

Consequences of Introduction: 

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

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

 Score: 3

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

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

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

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

Evaluate the host range of the pest:

Score: 3

Low (1) has a very limited host range.

Medium (2) has a moderate host range.

High (3) has a wide host range.

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

Evaluate the natural and artificial dispersal potential of the pest:

Score: 3

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

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

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

4) Economic Impact: False yellowhead can lower range productivity. It is unpalatable to livestock (Philbey and Morton, 2000). Furthermore, because of the barbs on the pappus of the seeds, it leads to enteritis and other gastrointestinal disease in livestock. As they are similar to those of Stinkwort, false yellow head is likely to have similar impacts on livestock. It is thought that false yellowhead would have similar impacts on grazing animals. Thirty years after introduction to South Australia, false yellowhead is a bad weeds of roadsides. Some people are allergic and develop severe dermatitis after contacting false yellowhead plants (Máñez et al., 1999; Hernández et al., 2001). It is also allelopathic to other plants and suppresses seed germination (Omezzine et al., 2011).  False yellowhead receives a Medium (2) in this category.

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

Economic Impact: D, F

A. The pest could lower crop yield.

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

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

D. The pest could negatively change normal cultural practices.

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

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

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

Economic Impact Score: 2

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

– Medium (2) causes 2 of these impacts.

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

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

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

Environmental Impact:  A, C, D

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

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

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

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

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

Score the pest for Environmental Impact:

Environmental Impact Score: 3

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

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

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

Consequences of Introduction to California for False yellowhead: High (14)

Add up the total score and include it here:

Low = 5-8 points

Medium = 9-12 points

High = 13-15 points

6) Post Entry Distribution and Survey Information: False yellowhead has been found in one county in California. It receives a Low (-1) in this category.

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

Score: -1

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

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

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

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

Final Score:

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

Uncertainty:

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

Conclusion and Rating Justification:

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

References:

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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


Responsible Party:

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


Comment Period: CLOSED

45-day comment period: Dec 1, 2016 – Jan 15, 2017


Pest Rating: A  |   Proposed Seed Rating: P

Parthenium hysterophorus L. | Santa Maria feverfew

2100033-Parthenium-hysterophorusL_CharlesTBryson-USDA-AgResearchService-Bugwood.org
California Pest Rating
Family: Asteraceae
Parthenium hysterophorus L. – Santa Maria feverfew
Former Pest Rating:  Q
CURRENT Pest Rating: A |  Proposed Seed Rating: P
Initiating Event:

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

Synonym:

Parthenium lobatum Buckley

History & Status:

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

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

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

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

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

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

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

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

Consequences of Introduction: 

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

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

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

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

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

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

Evaluate the host range of the pest.

Low (1) has a very limited host range.

Medium (2) has a moderate host range.

High (3) has a wide host range.

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

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

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

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

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

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

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

A. The pest could lower crop yield.

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

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

D. The pest could negatively change normal cultural practices.

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

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

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

Score the pest for Environmental Impact:

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

Medium (2) causes 2 of these impacts.

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

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

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

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

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

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

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

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

   Score the pest for Environmental Impact:

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

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

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

Consequences of Introduction to California for Santa Maria feverfew:

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

Low = 5-8 points

Medium = 9-12 points

High = 13-15 points

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

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

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

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

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

Final Score:

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

Uncertainty:

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

Conclusion and Rating Justification:

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

References:

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

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

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

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

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

National Plant Germplasm System: GRIN database: USDA APHIS

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

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

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

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

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

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

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

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

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

Responsible Party:

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


Comment Period:  CLOSED

45-day comment period: Nov 2 – Dec 17, 2016


Pest Rating: A |  Proposed Seed Rating: P

 

Fallopia japonica, F. sachalinensis, & F. X bohemica

California Pest Rating
Giant knotweeds
Fallopia japonica, F. sachalinensis, & F. X bohemica
Former Pest Rating:  A, Q
CURRENT Pest Rating: A |  Proposed Seed Rating: R
Initiating Event:

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

History & Status:

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

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

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

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

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

This risk giant knotweeds pose to California is evaluated below.

Consequences of Introduction: 

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

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

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

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

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

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

Low (1) has a very limited host range.

Medium (2) has a moderate host range.

High (3) has a wide host range.

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

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

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

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

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

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

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

A. The pest could lower crop yield.

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

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

D. The pest could negatively change normal cultural practices.

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

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

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

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

Medium (2) causes 2 of these impacts.

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

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

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

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

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

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

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

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

Score the pest for Environmental Impact. Score: 3

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

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

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

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

Consequences of Introduction to California for giant knotweeds:

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

Low = 5-8 points

Medium = 9-12 points

High = 13-15 points

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

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

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

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

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

Final Score:

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

Uncertainty:

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

Conclusion and Rating Justification:

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

Literature:

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

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

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

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

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

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


Responsible Party:

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


Comment Period:  CLOSED

45-day comment period: Aug 19 – Oct 3, 2016


Pest Rating: A |  Proposed Seed Rating: R

Parrotfeather Myriophyllum aquaticum (Vell.) Verdc.

California Pest Rating
Parrotfeather Myriophyllum aquaticum (Vell.) Verdc.
Saxifragales; Haloragaceae
Former Pest Rating:  Q
CURRENT Pest Rating: C |  Proposed Seed Rating: R
Initiating Event:

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

History & Status:                                  

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

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

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

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

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

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

California Interceptions. Sent to CDFA by land managers.

Consequences of Introduction: 

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

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

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

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

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

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

Low (1) has a very limited host range.

Medium (2) has a moderate host range.

High (3) has a wide host range.

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

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

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

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

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

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

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

A. The pest could lower crop yield.

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

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

D. The pest could negatively change normal cultural practices.

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

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

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

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

Medium (2) causes 2 of these impacts.

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

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

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

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

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

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

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

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

Score the pest for Environmental Impact. Score: 3

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

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

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

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

Consequences of Introduction to California for Uruguayan water primrose:

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

Low = 5-8 points

Medium = 9-12 points

High = 13-15 points

6) Post Entry Distribution and Survey Information: Evaluate the known distribution in California. Only official records identified by a taxonomic expert and supported by voucher specimens deposited in natural history collections should be considered. Pest incursions that have been eradicated, are under eradication, or have been delimited with no further detections should not be included. Score: -3

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

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

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

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

Final Score:

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

Uncertainty:

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

Conclusion and Rating Justification:

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

References:

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

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

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

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

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


Responsible Party:

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


Comment Period: CLOSED

45-day comment period: Aug 19 – Oct 3, 2016


Pest Rating: C |  Proposed Seed Rating: R

 

Crupina vulgaris Pers. ex. Cass.: bearded creeper

common-crupina_1459126-UtahStateUniv-bugwood-WEB
California Pest Rating
Crupina vulgaris Pers. ex. Cass.:  bearded creeper
Asteridae: Asteraceae
Former Pest Rating:  A
CURRENT Pest Rating: A | Proposed Seed Rating: P
Initiating Event:

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

History & Status:

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

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

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

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

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

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

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

Consequences of Introduction: 

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

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

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

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

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

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

Evaluate the host range of the pest. Score:

Low (1) has a very limited host range.

Medium (2) has a moderate host range.

High (3) has a wide host range.

3) Pest Dispersal Potential: Bearded creeper produces via numerous seeds that seem to be able to spread rather slowly. The seed bank is moderately persistent. Once established, bearded creeper can persist and has proven difficult to eradicate. Bearded creeper receives a Medium (2) in this category.

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

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

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

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

4) Economic Impact: Bearded creeper can lower range productivity, land value, and can trigger state quarantines. Bearded creeper receives a High (3) in this category.

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

A. The pest could lower crop yield.

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

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

D. The pest could negatively change normal cultural practices.

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

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

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

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

Medium (2) causes 2 of these impacts.

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

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

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

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

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

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

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

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

Score the pest for Environmental Impact. Score:

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

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

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

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

Add up the total score and include it here.

Low = 5-8 points

Medium = 9-12 points

High = 13-15 points

6) Post Entry Distribution and Survey Information: Bearded creeper has been found in in 2 counties in California. It receives a Low (-1) in this category.

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

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

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

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

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

Final Score

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

Uncertainty:

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

Conclusion and Rating Justification:

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

References:

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

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

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

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

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

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


Responsible Party:

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


Comment Period:

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


Comment Format:

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

Example Comment: 

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

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♦  Comments may not be posted if they:

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

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


Pest Rating: A | Proposed Seed rating: P

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

California Pest Rating
Mantisalca salmantica (L.) Briq. & Cavill.: Dagger-flower
Synonym: Centaurea salmantica L.
Asterales; Asteraceae
Former Pest Rating:  Q
CURRENT Pest Rating: A |  Proposed Seed Rating: P
Initiating Event:

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

History & Status:

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

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

Official Control: None.

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

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

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

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

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

Consequences of Introduction: 

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

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

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

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

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

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

Low (1) has a very limited host range.

Medium (2) has a moderate host range.

High (3) has a wide host range.

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

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

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

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

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

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

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

A. The pest could lower crop yield.

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

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

D. The pest could negatively change normal cultural practices.

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

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

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

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

Medium (2) causes 2 of these impacts.

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

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

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

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

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

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

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

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

Score the pest for Environmental Impact. Score: 3

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

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

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

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

Consequences of Introduction to California for Dagger-flower:

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

Low = 5-8 points

Medium = 9-12 points

High = 13-15 points

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

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

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

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

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

Final Score

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

Uncertainty:

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

Conclusion and Rating Justification:

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

References:

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

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

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

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

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

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

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

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


Responsible Party:

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


Comment Period:  CLOSED

The 45-day comment period opened on Jun 30, 2016 and closed on Aug 14, 2016.


Pest Rating: A |  Proposed Seed Rating: P

Schoenoplectus articulatus (L.) Palla: Jointed bulrush

California Pest Rating
Family: Cyperaceae
Schoenoplectus articulatus (L.) Palla: Jointed bulrush
Synonym: Scirpus articulatus L.
Former Pest Rating:  Q
CURRENT Pest Rating: D |  Proposed Seed Rating: N/A
Initiating Event:

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

History & Status:

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

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

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

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

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

Consequences of Introduction: 

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

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

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

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

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

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

Low (1) has a very limited host range.

Medium (2) has a moderate host range.

High (3) has a wide host range.

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

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

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

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

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

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

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

A. The pest could lower crop yield.

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

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

D. The pest could negatively change normal cultural practices.

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

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

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

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

Medium (2) causes 2 of these impacts.

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

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

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

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

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

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

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

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

Score the pest for Environmental Impact. Score: 2

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

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

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

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

Consequences of Introduction to California for Jointed bulrush:

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

Low = 5-8 points

Medium = 9-12 points

High = 13-15 points

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

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

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

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

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

Final Score

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

Uncertainty:

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

Conclusion and Rating Justification:

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

References:

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

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

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

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

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


Responsible Party:

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


Comment Period:  CLOSED

The 45-day comment period opened on Jun 30, 2016 and closed on Aug 14, 2016.


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