Category Archives: Fungi

Chrysanthemum white rust – Puccinia horiana (Hennings 1901)

California Pest Rating Proposal for

Chrysanthemum white rust | Puccinia horiana (Hennings 1901)
Current Rating: Q
Proposed Rating: A

Comment Period: 6/6/2019 through 7/21/2019


Author/Responsible Party:

Dr. Heather J. Scheck, Primary State Plant Pathologist/Nematologist, California Department of Food and Agriculture, 204 West Oak Ave, Lompoc, CA 805-736-8050 email: plant.health[@]cdfa.ca.gov.

*NOTE:

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

Comment Format:

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

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

Posted comments will not be able to be viewed immediately.

Comments may not be posted if they:

  • Contain inappropriate language which is not germane to the
    pest rating proposal;
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    pornographic, sexually oriented, threatening, racially offensive,
    discriminatory or illegal material;
  • Violates agency regulations prohibiting sexual harassment or 
    other forms of discrimination;
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    including threats.

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

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


Proposed Pest Rating: A


Posted by ls

Colletotrichum fioriniae

California Pest Rating Proposal for

Colletotrichum fioriniae (Marcelino & Gouli) Pennycook 2017
Current Pest Rating: Z
Proposed Pest Rating: B


*Comment Period: 4/17/2019 through 6/1/2019


Author/Responsible Party:

John J. Chitambar, Primary Plant Pathologist/Nematologist, California Department of Food and Agriculture, 3294 Meadowview Road, Sacramento, CA 95832. Phone: 916-738-6693, plant.health[@]cdfa.ca.gov.


*NOTE:

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


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

EXAMPLE COMMENT:

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

Posted comments will not be able to be viewed immediately.

Comments may not be posted if they:

  • Contain inappropriate language which is not germane to the pest rating proposal;
  • Contains defamatory, false, inaccurate, abusive, obscene, pornographic, sexually oriented, threatening, racially offensive, discriminatory or illegal material;
  • Violates agency regulations prohibiting sexual harassment or other forms of discrimination;
  • Violates agency regulations prohibiting workplace violence, including threats.

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

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


Proposed Pest Rating: B


Posted by ls

Erysiphe peckii (U. Braun) U. Braun & S. Takam. 2000

California Pest Rating Proposal for

Erysiphe peckii (U. Braun) U. Braun & S. Takam. 2000
Current Pest Rating: Q

Proposed Pest Rating: B
*Comment Period: 4/4/2019 – 5/19/2019

Author/Responsible Party:

John J. Chitambar, Primary Plant Pathologist/Nematologist, California Department of Food and Agriculture, 3294 Meadowview Road, Sacramento, CA 95832. Phone: 916-738-6693, plant.health[@]cdfa.ca.gov.


*NOTE:

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


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

EXAMPLE COMMENT:

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

Posted comments will not be able to be viewed immediately.

Comments may not be posted if they:

  • Contain inappropriate language which is not germane to the pest rating proposal;
  • Contains defamatory, false, inaccurate, abusive, obscene, pornographic, sexually oriented, threatening, racially offensive, discriminatory or illegal material;
  • Violates agency regulations prohibiting sexual harassment or other forms of discrimination;
  • Violates agency regulations prohibiting workplace violence, including threats.

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

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


Proposed Pest Rating: B

Posted by ls

Ilyonectria capensis L. Lombard & Crous 2013

California Pest Rating Proposal

Ilyonectria capensis L. Lombard & Crous 2013  
Current Pest Rating: Q
Proposed Pest Rating: C


Comment Period:  2/22/2019 – 4/8/2019*


Author/Responsible Party:

John J. Chitambar, Primary PlantPathologist/Nematologist, California Department of Food and Agriculture, 3294Meadowview Road, Sacramento, CA 95832. Phone: 916-262-1110, plant.health[@]cdfa.ca.gov.


*NOTE:

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


Comment Format:

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

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


Posted comments will not be able to be viewed immediately.


Comments may not be posted if they:

  • Contain inappropriate language which is not germane to the
    pest rating proposal;
  • Contains defamatory, false, inaccurate, abusive, obscene, 
    pornographic, sexually oriented, threatening, racially offensive,
    discriminatory or illegal material;
  • Violates agency regulations prohibiting sexual harassment or 
    other forms of discrimination;
  • Violates agency regulations prohibiting workplace violence, 
    including threats.

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


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


Proposed Pest Rating: C


Posted by ls 

Neocercosporidium smilacis (Thüm.) U. Braun, C. Nakash., Videira & Crous 2017

California Pest Rating Proposal

Neocercosporidium smilacis (Thüm.) U. Braun, C. Nakash., Videira & Crous 2017
Current Pest Rating: Q
Proposed Pest Rating: B


Comment Period: 2/22/2019 – 4/8/2019*

Author/Responsible Party:

John J. Chitambar, Primary PlantPathologist/Nematologist, California Department of Food and Agriculture, 3294Meadowview Road, Sacramento, CA 95832. Phone: 916-262-1110, plant.health[@]cdfa.ca.gov.


*NOTE:

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


Comment Format:

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

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


Posted comments will not be able to be viewed immediately.


Comments may not be posted if they:

  • Contain inappropriate language which is not germane to the
    pest rating proposal;
  • Contains defamatory, false, inaccurate, abusive, obscene,
    pornographic, sexually oriented, threatening, racially offensive,
    discriminatory or illegal material;
  • Violates agency regulations prohibiting sexual harassment or
    other forms of discrimination;
  • Violates agency regulations prohibiting workplace violence,
    including threats.

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


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


Proposed Pest Rating: B


Posted by ls 


Gymnosporangium yamadae

California Pest Rating Proposal

Gymnosporangium yamadae Miyabe ex G. Yamada 1904
Current Pest Rating: Q
Proposed Pest Rating: A


Comment Period: 1/18/2019 – 3/4/2019*


Responsible Party:

John J. Chitambar, Primary PlantPathologist/Nematologist, California Department of Food and Agriculture, 3294Meadowview Road, Sacramento, CA 95832. Phone: 916-262-1110, plant.health[@]cdfa.ca.gov.


*NOTE:

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


Comment Format:

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

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

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

♦  Comments may not be posted if they:

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

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

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

Violates agency regulations prohibiting workplace violence, including threats.

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

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


Proposed Pest Rating: A


Posted by ls 

Cercospora insulana Sacc. 1915

California Pest Rating for
Cercospora insulana Sacc. 1915
Pest Rating: C

PEST RATING PROFILE

Initiating Event: 

On May 11, 2018 a postal shipment of statice dried flowers showing symptoms of leaf spots was intercepted by the CDFA at a Federal Express (FedEx) office.  The shipment was destined to a private owner in Alameda County and had originated in Hawaii.  A sample of the symptomatic flowers was sent to the CDFA Plant Pathology Lab for disease diagnoses.  On May 17, 2018 Cheryl Blomquist, CDFA plant pathologist, identified the fungus, Cercospora insulana associated with the leaf spots.  The present status and rating of C. insulana is reevaluated here.

History & Status:

Background:  Cercospora insulana is a fungal plant pathogen in the Mycosphaerellaceae family, that causes leaf spot of statice and other host plants.

The pathogen is globally widespread.  In the USA, Cercospora insulana has only been reported from Florida and California (Farr & Rossman, 2018).  In California, prior to its most recent detection, the pathogen has been reported on Armeria sp. and Limonium spp. in northern and southern coastal region of California (French, 1989).

Disease cycle: In general, plants infected with Cercospora species produce conidiophores (specialized hypha) that arise from the plant surface in clusters through stomata and form conidia (asexual spores) successively.  Conidia are easily detached and blown by wind often over long distances.  On landing on surfaces of a plant host, conidia require water or heavy dew to germinate and penetrate the host.  Substomatal stroma (compact mycelial structure) may form from which conidiophores develop.  Development of the pathogen is favored by high temperatures and the disease is most destructive during summer months and warmer climates.  High relative humidity is necessary for conidial germination and plant infection.  The pathogen can overwinter in or on seed and as mycelium (stromata) in old infected leaves (Agrios, 2005).   

Dispersal and spread: Dispersal and spread: air-currents, infected nursery plants, infected leaves, seeds (Agrios, 2005).

Hosts: Armeria sp., A. maritima (thrift seapink), Limonium sp., L. bonducellii (Algerian statice), L. californicum (California sea lavender/marsh rosemary), L. gmelinii (syn. Statice gmelinii; Siberian statice), L. sinuatum (syn. Statice sinuata; statice/wavyleaf sea lavender), L. vulgare (common sea lavender) (CABI, 2018; French, 1989); Nerium indicum (Indian oleander) (XueWen et al., 2017)

Symptoms:  Leaf spot symptoms caused by Cercospora insulana in field-grown statice were reported from Italy as circular, brown lesions with a darker edge, 3-6 mm in diameter and surrounded by an orange or reddish halo.  Old lesions enlarged and coalesced, causing yellowing and senescence of leaves.  Heavy infections resulted in severe defoliation and retarded growth or death in panicles. Lesions were also present on the wings of the flower scapes, while scapes proper were not involved (Nicoletti et al., 2003).

Damage Potential: Quantitative losses due to Cercospora insulana have not been reported.  If left uncontrolled, leaf spotting may lead to disease outbreaks under favorable conditions, wherein photosynthetic areas can be reduced.  Heavy infections may result in severe defoliation, retarded plant growth and death of flowers in statice, and likely, in other ornamental host plants.  Nursery productions of ornamental hosts under controlled and conducive conditions for pathogen development would also be of concern in California.  However, damage potential due to this pathogen is likely to be similar to other Cercospora diseases which is usually low (Agrios, 2005).  Furthermore, fungicide applications and sanitary measures including the use of clean seed have been used to successfully control Cercospora diseases (Agrios, 2005).

Worldwide Distribution: Asia: China (XueWen et al., 2017), India, Myanmar; Africa: Kenya, Malta, South Africa, Zimbabwe; Europe: Caucasus, Italy, Portugal, Russia: North America: USA (California, Florida), Haiti; Oceania: Australia, New Zealand (Farr & Rossman, 2018)

Official Control: Presently, Cercospora insulana is on the ‘Harmful Organism’ list for Brazil, Colombia, Ecuador and Israel (USDA PCIT, 2018).

California Distribution:  Cercospora insulana is distributed in northern and southern coastal areas of the State (French, 1989).

California Interceptions To date, the recent detection of C. insulana (see ‘initiating event’) has been the only interception reported.

The risk Cercospora insulana would pose to California is evaluated below.

Consequences of Introduction: 

1) Climate/Host Interaction: Cercospora insulana has only been detected in northern and southern coastal regions in California. These limited regions provide adequate moisture that favor development of the pathogen in host plants like statice.

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: The known host range is limited to statice, thrift seapink and Indian oleander in the genera Limonium, Armeria and Neria.

Evaluate the host range of the pest. Score: 1

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: Cercospora insulana has high reproductive potential resulting in the successive production of conidia which primarily depend on air currents, infected plants and seed for dispersal and spread.

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: Quantitative losses due to Cercospora insulana have not been reported. However, for nurseries particularly, infected host plants with leaf spots could result in lowered value resulting in use of fungicidal treatments thereby increasing production costs, and loss of markets.

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

Economic Impact: B, C

A. The pest could lower crop yield.

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

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

D. The pest could negatively change normal cultural practices.

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

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

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

Economic Impact Score: 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: Home garden plantings of statice species may be impacted if the pathogen was to establish under favorable environmental conditions and in the absence of adequate disease control.  The pathogen has not been detected in oleander in California.

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

Environment Impact: E 

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

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

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

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

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

Environmental Impact Score: 2

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

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

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

Consequences of Introduction to California for Cercospora insulana:

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

-Low = 5-8 points

Medium = 9-12 points

-High = 13-15 points

Total points obtained on evaluation of consequences of introduction to California = 10

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.

Evaluation is ‘Medium’ in California.

Score: (-2)

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

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

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

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

Final Score:

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

Final Score:  Score of Consequences of Introduction – Score of Post Entry Distribution and Survey Information = 8

Uncertainty:  

None.

Conclusion and Rating Justification:

Based on the evidence provided above the proposed rating for Cercospora insulana is to continue as C.


References:

Agrios, G. N.  2005.  Plant Pathology (Fifth Edition).  Elsevier Academic Press, USA.  922 p.

Farr, D.F., & A. Y. Rossman.  2016.  Fungal Databases, Systematic Mycology and Microbiology Laboratory, ARS, USDA.  Retrieved May 18, 2018, from http://nt.ars-grin.gov/fungaldatabases/

French, A. M. 1989. California Plant Disease Host Index. California Department of Food and Agriculture, Sacramento (Updated online version by T. Tidwell, May 2, 2017).

Nicoletti, R., F. Raimo, C. Pasini, and F. D’Aquila.  2003.  Occurrence of Cercospora insulana on statice (Limonium sinuatum) in Italy.  Plant Pathology 52: 418.  DOI: 10.1046/j.1365-3059.2003.00840.x

USDA PCIT.  2018.  USDA Phytosanitary Certificate Issuance & Tracking System. Retrieved May 18, 2018. 12:45:06 pm CDT.  https://pcit.aphis.usda.gov/PExD/faces/ReportHarmOrgs.jsp.

XueWen, X., Z. Qian and G. YingLan.  2017.  New records of Cercospora and Pseudocercospora in China.  Mycosystema 36: 1164-1167.


Responsible Party:

John J. Chitambar, Primary Plant Pathologist/Nematologist, California Department of Food and Agriculture, 3294 Meadowview Road, Sacramento, CA 95832. Phone: 916-738-6693, plant.health[@]cdfa.ca.gov.


Comment Period:* CLOSED

9/13/18 – 10/28/18


*NOTE:

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


Comment Format:

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

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

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

♦  Comments may not be posted if they:

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

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

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

Violates agency regulations prohibiting workplace violence, including threats.

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

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


Pest Rating: C


Posted by ls 

Corynespora cassiicola (Berk. & M. A. Curtis) C. T. Wei 1950

California Pest Rating for
Corynespora cassiicola (Berk. & M. A. Curtis) C. T. Wei 1950
Pest Rating: B

 


PEST RATING PROFILE

Initiating Event: 

On September 27, 2017, a shipment of desert rose (Adenium obesum) plants showing symptoms of leaf spot disease was intercepted by San Diego Agricultural County inspectors.  The shipment had originated in Florida and was destined to a private company in San Diego County.  A sample of symptomatic plant leaves was collected by the San Diego Agriculture County and sent to the CDFA Plant Pathology Laboratory in Sacramento.  On October 18, 2017, the fungus, Corynespora cassiicola, was identified by CDFA plant pathologist, Suzanne Latham, to be associated with the leaf spot symptoms. A temporary ‘Q’ rating was assigned to the pathogen and consequently, the shipment was destroyed.  Corynespora cassiicola was previously detected on May 7, 2008, in an intercepted shipment of Mandevilla plants that originated in Florida and was destined to a nursery in San Diego County.  This detection marked the first report of the pathogen in California and resulted in the destruction of the shipment.  The current rating and consequences of introduction of C. cassiicola in California are assessed here and a permanent rating is proposed.

History & Status:

Background:  Corynespora cassiicola is a fungal plant pathogen that attacks a wide range of plants from tropical and subtropical countries causing leaf spot disease in several economically important crops under different common names such as Corynespora leaf spot of cucumber and several other hosts, blotch disease of cucurbits, stem and fruit spot of eggplant, papaya and target spot of tomato and cotton.  The fungus has been found in plant leaves, stems, fruit, roots, nematode cysts, and human skin and comprises many isolates.  Majority of isolates reported have been obtained from lesions or from fulfilled Koch postulate trials and are known to be plant pathogens.  However, isolates have also been reported from dead organic matter and non-symptomatic plant tissue and some can be both depending on the host substrate (Dixon et al., 2009).  Isolates may vary in virulence in host specificity.  Some isolates that specifically parasitize weed hosts without affecting agricultural crops may serve as potential bioherbicides agents (Smith & Schlub, 2005).  In South-east Asia, C. cassiicola causes leaf fall disease of rubber, which is one of the most serious leaf diseases of rubber in that region.

The pathogen was first described as Helminthosporium cassiicola by Berkeley and Curtis in 1868, and subsequently underwent several taxonomic changes to now be known as Corynespora cassiicola (Farr & Rossman, 2018). This pathogen is ubiquitous and has been reported to cause major economic losses in more than 70 countries (Dixon et al., 2009).

Disease cycle:  The pathogen survives in infested plant materials for more than two years.  High humidity, warm temperature (25-32°C) and long days are necessary for conidia production, infection and disease development.  Fluctuating day and night temperatures favor disease development (Williams, 1996).  The disease develops in tomatoes at favorable temperatures of 20-28°C and infection can occur at 16-32°C.  Extended periods of 16 to 44 hours of high moisture are necessary for optimum disease development (Pernezney et al., 2014).

Dispersal and spread: Infested planting stock, plant material, plant debris.  Conidia (spores) are airborne and seedborne (Daughtrey et al., 1995).

Hosts: More than 530 plant species from 380 genera including monocots, dicots, ferns, and one cycad have been reported to support growth of C. cassiicola (Dixon et al., 2009). Economically important host crops for California include Cucumis sativus (cucumber), Cucurbita moschata (pumpkin), C. moschata (pumpkin), C. pepo (marrow), cucurbits, Gossypium sp. (cotton), Solanum lycopersicum (tomato), S. melongena (eggplant) and ornamentals (CABI, 2018; Farr & Rossman, 2018).  Ornamental hosts include Aeschyanthus pulcher (lipstick vine), Aphelandra squarrosa (zebra plant), Catharnathus roseus (Madagascar periwinkle), Begonia, Hydrangea macrophylla (bigleaf hydrangea), Euphorbia pulcherrima (poinsettia), Saintpaulia ionantha (African violet) and Salvia splendens (scarlet sage) (Daughtrey et al., 1995)

Symptoms:  The initial symptoms of target spot in tomato are pinpoint-size, water-soaked lesions on the upper surfaces of leaves. These lesions increase in size, turn circular and pale brown with individual yellow halos.  Over time lesions coalesce and tissue may collapse while the leaflet remains attached to the petiole. Similar lesions may develop on petioles and stems resulting in rapid collapse of affected leaflets.  Lesions can develop on young fruit and resemble those caused by abiotic factors. These lesions are initially dark, sunken, pinpoint and brown and may later develop into craters. On ripe fruit, large, circular lesions develop with pale brown centers that crack and over time create avenues for secondary invading pathogens (Pernezny et al., 2014).  In infected cucurbits, initial lesions are angular yellow spots with light brown centers and dark brown borders.  As these lesion age, they drop out. Young and green fruit are not susceptible however, early infection of the blossom end of fruit may result in shriveling and darkening of the infected area with dark sporulation (Williams, 1996).  On ornamental plants such as poinsettia, lesions may be irregular, large and brown on bracts and primarily at the tips and margins of leaves; on hydrangea lesions may be small, reddish purple, circular with tan centers and reddish-purple margins; on African violets lesions are irregular and brown (Daughtrey et al., 1995).

Damage Potential: In the USA, reports of losses from target spot of field tomatoes are restricted to the Southeast which is frequented with high humidity and warm temperature climate (Pernezny et al., 2014). In California, if left uncontrolled, Corynespora disease development is likely to occur in greenhouses under favorable temperature and high humidity conditions. Impact of disease caused by this pathogen may be mitigated through proper sanitation, use of resistant varieties and regular applications of fungicidal treatments.

Worldwide Distribution: Asia: Bangladesh, Brunei Darussalam, Cambodia, China, India, Indonesia, Japan, Republic of Korea, Laos, Malaysia, Maldives, Myanmar, Nepal, Pakistan, Philippines, Singapore, Sri Lanka, Taiwan, Thailand, Vietnam, Yemen; Africa: Benin, Cameroon, Congo, Democratic Republic of Congo, Côte d’Ivoire, Egypt, Ethiopia, Gabon, Ghana, Guinea, Liberia, Mauritius, Nigeria, Seychelles, Sierra Leone, South Africa, Sudan, Tanzania, Togo, Uganda, Zambia; Central America and Caribbean:  Antigua and Barbuda, Barbados, Belize, British Virgin Islands, Costa Rica, Cuba, Dominica, El Salvador, Guadeloupe, Guatemala, Haiti, Honduras, Jamaica, Nicaragua, Puerto Rico, Trinidad and Tobago, United States Virgin Islands; Europe: Austria, Bulgaria, Denmark, France, Germany, Hungary, Italy, Netherlands, Norway, Romania, Russian Federation, United Kingdom, Ukraine; North America: Canada, Mexico, USA; Oceania: American Samoa, Australia, Fiji, Guam, Micronesia, New Zealand, northern Mariana Islands, Palau, Papua New Guinea, Samoa, Solomon Islands, Vanuatu; South America: Argentina, Bolivia, Brazil, Colombia, Ecuador, French Guiana, Guyana, Venezuela (CABI, 2018).

In the United States, C. cassiicola has been reported from Alabama, Florida, Hawaii, Illinois, Iowa, Louisiana, Minnesota, Mississippi, Nebraska, New York, North Carolina, North Dakota, South Carolina, Tennessee, Virginia, and Wisconsin (CABI, 2018).

Official Control: Corynespora cassiicola is on the ‘Harmful Organism Lists” for Israel, Namibia, South Africa and Vietnam (USDA PCIT, 2018).

California Distribution: Corynespora cassiicola has not been reported from California.  The pathogen is not known to be established in California.

California Interceptions:  There have been two interceptions of plants infected with Corynespora cassiicola (see: ‘Initiating Event’).

The risk Corynespora cassiicola would pose to California is evaluated below.

Consequences of Introduction: 

1) Climate/Host Interaction: Corynespora cassiicola requires prolonged periods of high humidity (16-44 hours) and warm temperature (25-32°C) for disease development. These climatic conditions would limit the ability of the pathogen to establish and spread within California.

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.

2) Known Pest Host Range: The pathogen has a very wide and diverse host range that comprises more than 530 plant species from 380 genera including monocots, dicots, ferns, and one cycad. Economically important host crops for California include cucurbits, cotton, tomato, eggplant and ornamentals.

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: Conidia are produced in abundance and are dispersed by air currents, infected seeds, host plant material and debris. Therefore, a high score is given to 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: Plant damage caused by cassiicola is more likely under prolonged periods of high humidity and warm temperatures found in greenhouse cultivation than in open field environments of the state. If left uncontrolled, infections by the pathogen could result in lower crop yield and value resulting in the loss of markets. However, the administration of proper control measures may mitigate impact of damage caused by this pathogen.  Therefore, a medium score is given to this category.

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

Economic Impact: A, B

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:  No significant impact to the environment is likely as the requirements of prolonged, high humidity and warm temperatures would considerably limit the ability of cassiicola to establish within the state.  

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

Environment Impact:  None

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

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

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

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

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

Environmental Impact Score: 1

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

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

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

Consequences of Introduction to California for Corynespora cassiicola:

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

-Low = 5-8 points

Medium = 9-12 points

-High = 13-15 points

Total points obtained on evaluation of consequences of introduction to California = 10

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.

Evaluation is ‘Not established’ in California and has only been detected in intercepted plant shipments to the State.

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: (Score)

Final Score:  Score of Consequences of Introduction – Score of Post Entry Distribution and Survey Information = 10

Uncertainty:

None.

Conclusion and Rating Justification:

Based on the evidence provided above the proposed rating for Corynespora cassiicola is B.


References:

Agrios, G. N.  2005.  Plant Pathology (Fifth Edition).  Elsevier Academic Press, USA.  922 p.

Daughtrey, M. L., Wick, R. L., and Peterson, J. L.  1995.Corynespora leaf spot of Catharanthus, Hydrangea, Poinsettia, and SaintpauliaIn, Compendium of Flowering Potted Plant Diseases. APS Press, The American Phytopathological Society 90p.

Dixon, L. J., Schlub, R. L., Pernezny, K., and Datnoff, L. E.  2009.  Host specialization and phylogenetic diversity of Corynespora cassiicola.  Phytopathology 99: 1015-1027.

Farr, D.F., and Rossman, A. Y.  2016.  Fungal Databases, Systematic Mycology and Microbiology Laboratory, ARS, USDA.  Retrieved August 1, 2016, from http://nt.ars-grin.gov/fungaldatabases/

Pernezny, K. L., Blazquez, C. H., Smith, L. J., and Schlub, R. L.  2014).  Target spot.  In, Compendium of Tomato Disease and Pests Second Edition, Edited by J. B. Jones, T. A. Zitter, T. M. Momol, and S. A. Miller. 44-46p.

Smith, L. J., and Schlub, R. L. 2005. Foliar fungi on weeds of Guam and the potential for Corynespora cassiicola as a bioherbicide for   Stachytarpheta jamaicensis. (Abstr.) Phytopathology 95: S93.

USDA PCIT.  2017.  USDA Phytosanitary Certificate Issuance & Tracking System. Retrieved May 23, 2018. 11:53:45 am CDT.  https://pcit.aphis.usda.gov/PExD/faces/ReportHarmOrgs.jsp.

Williams, P. H.  1996.  Target leaf spot.  In, Compendium of Cucurbit Diseases, Ed. T. A. Zitter, D. L. Hopkins, and C. E. Thomas.  APS Press, The American Phytopathological Society p 31-32.


Responsible Party:

John J. Chitambar, Primary Plant Pathologist/Nematologist, California Department of Food and Agriculture, 3294 Meadowview Road, Sacramento, CA 95832. Phone: 916-262-1110, plant.health[@]cdfa.ca.gov.


Comment Period:* CLOSED

5/31/18 – 7/15/18


*NOTE:

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


Comment Format:

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

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

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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.

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Pest Rating: B

 


Posted by ls 

 

 

Pseudocercospora theae

California Pest Rating for
Pseudocercospora theae (Cavara) Deighton 1987
Pest Rating: C

 


PEST RATING PROFILE

Initiating Event: 

On March 6, 2018, the USDA APHIS PPQ requested State Regulatory Officials to review PPQ’s consideration of deregulation of the pathogen, Pseudocercospora theae at US ports of entry.  A ‘Deregulation evaluation of established pests’ report prepared by PERAL was provided for this review.  Therefore, the risk of infestation of P. theae in California is evaluated and a permanent rating is herein proposed.

History & Status:

Background:  Pseudocercospora theae is a fungal plant pathogen in the Mycosphaerellaceae family, that causes leaf spotting known as, bird’s eye spot disease of tea (Camellia spp.). The pathogen has previously been known by its synonyms, Septoria theae and Cecoseptoria theae (Braun et al., 2012; Farr & Rossman, 2018). Holliday (1980) reported that the fungus causes a “very minor” leaf-spotting disease in tea plants.

Pseudocercospora theae has not been reported in California. In the USA, the pathogen has been reported in Florida since about 1955 and disease caused by P. theae has not been reported after 1998.  It is likely that the pathogen is present at non-detectable levels and kept under control by standard disease management practices in nurseries (PPQ, 2018).

Disease cycle: While information on the specific biology of Pseudocercospora theae is limited, it is likely that its disease cycle is like that of other members of the genus.  Generally, Pseudocercospora-infected plants produce conidiophores (specialized hypha) that arise from the plant surface in clusters through stomata and form conidia (asexual spores) successively.  Conidia are easily detached and blown by wind often over long distances.  On landing on surfaces of a plant host, conidia require water or heavy dew to germinate and penetrate the host.  Substomatal stroma (compact mycelial structure) may form from which conidiophores develop.  Development of the pathogen is favored by high temperatures and the disease is most destructive during summer months and warmer climates.  High relative humidity is necessary for conidial germination and plant infection.  The pathogen can overwinter in or on seed and as mycelium (stromata) in old infected leaves (Agrios, 2005).    

Dispersal and spread: Specific information for Pseudocercospora is lacking, however, its mode of dispersal is likely to be like other species of the genus and include air-currents, rain splash/drops, infected plants and propagative material (PPQ, 2018).

Hosts: Camelia sp., C. japonica (Japanese camellia), C. sasanqua (sasanqua camellia), C. sinensis (tea tree; synonyms: Thea assamica, T. sinensis) (Farr & Rossman, 2018).  Although some species of Pseudocercospora are capable of infecting different hosts within a single family (Crous, et al., 2013), there is no evidence that this is true for P. theae (PPQ, 2018).

Symptoms:  Infected host plants exhibit circular leaf spots no greater than 2-3 mm diam., on both sides of a leaf.  The spots are at first purple red, with an indefinite yellow green border and turn white with a narrow purple red ring (Holliday, 1980) with a narrow, raised rim, followed by a dark marginal line or halo (Braun et al., 2012).

Damage Potential: Specific losses due to Pseudocercospora theae have not been reported.  Ornamental plantings of Camellia species may be affected in limited regions of California with sufficient moisture for pathogen infection and development. The climatic suitability of the pathogen encompasses Hardiness Zones 10-13 (PPQ, 2018; Margery et al., 2008).  Nursery production of Camellia species under controlled and conducive conditions for pathogen development would also be of concern in California.  However, P. theae outbreaks in Florida nurseries were successfully controlled by use of proper sanitation practices and fungicide applications (PPQ, 2018), therefore, it is likely that the same will be true for California.  If left uncontrolled, leaf spotting may lead to disease outbreaks under favorable conditions, wherein photosynthetic areas can be reduced, and in severe infections, leaf wilt and drop may be expected.

Worldwide Distribution: Asia: Nepal, Indonesia, India, China, Taiwan, Pakistan, Sri Lanka, Vietnam; Africa: Ethiopia, Malawi, Mauritius, Tanzania, Uganda; Europe: Georgia, Italy, Netherlands Antilles; North America: Florida; South America: Argentina, Brazil, Peru (Braun et al., 2012; EPPO, 2018; Farr & Rossman, 2018).

Official Control: Presently, Pseudocercospora theae is on the ‘Harmful Organism’ list for Colombia (USDA PCIT, 2018).

California Distribution: Pseudocercospora theae has not been reported from California.  The pathogen is not known to be established in California.

California Interceptions:  None reported.

The risk Pseudocercospora theae would pose to California is evaluated below.

Consequences of Introduction:

1) Climate/Host Interaction: Limited parts of California with adequate moisture, as in coastal regions of the State where Camellia species are grown, are likely to favor establishment of Pseudocercospora theae.

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: The host range is limited to Camellia [Camelia , C. japonica (Japanese camellia), C. sasanqua (sasanqua camellia), C. sinensis (tea tree)]

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: Reproduction is high and dispersal conidia is through windborne conidia, and rain splash or raindrops. The pathogen is also spread through infected plant propagative material.

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: Specific losses due to Pseudocercospora theae have not been reported. Ornamental plantings of Camellia species may be affected in limited regions of California with sufficient moisture for pathogen infection and development. Nursery production of Camellia species under controlled and conducive conditions for pathogen development would also be of concern in California.  However, theae outbreaks in Florida nurseries were successfully controlled by use of proper sanitation practices and fungicide applications (PPQ, 2018), therefore, it is likely that the same will be true for California.  Uncontrolled infected plants may lose value, however, with control measures adopted, the impact is expected to be low.

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

Economic Impact: B

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: Home garden plantings of Camellia species may be impacted if the pathogen was to establish under favorable environmental conditions and in the absence of adequate disease control.

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

Environment 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.

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 Pseudocercospora theae: 9

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

-Low = 5-8 points

Medium = 9-12 points

-High = 13-15 points

Total points obtained on evaluation of consequences of introduction to California = 9

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.

Evaluation is ‘Not established’ in California.

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: (Score)

Final Score:  Score of Consequences of Introduction – Score of Post Entry Distribution and Survey Information = 9

Uncertainty:

There is very limited information available on the biology of Pseudocercospora theae.

Conclusion and Rating Justification:

Based on the evidence provided above the proposed rating for Pseudocercospora theae is C.


References:

Agrios, G. N.  2005.  Plant Pathology (Fifth Edition).  Elsevier Academic Press, USA.  922 p.

Braun, U., M. Rybak, R. Rybak, and M. G. Cabrera.  2012.  Foliar diseases on tea and mate in Argentina caused by Pseudocercospora species.  Plant Pathology & Quarantine 2 (2): 103-110.  Doi 10.5943/ppq/2/2/2

Crous, P. W., U. Braun, G. C. Hunter, M. J. Wingfield, G. J. M. Verkley, H. -D. Shin, C. Nakashima and J. Z. Groenewald.  2013.  Phylogenetic lineage in Pseudocercospora.  Studies in Mycology 75: 37-114. Published online: 22 May 2012; doi:10.3114/sim0005. Hard copy: June 2013. www.studiesinmycology.org

EPPO.   2018.   Pseudocercospora theae (CERSTH).  PQR database.  Paris, France: European and Mediterranean Plant Protection Organization.  https://gd.eppo.int/

Farr, D.F., & A. Y. Rossman.  2016.  Fungal Databases, Systematic Mycology and Microbiology Laboratory, ARS, USDA.  Retrieved August 1, 2016, from http://nt.ars-grin.gov/fungaldatabases/

Holliday, P.  1980.  Fungus diseases of tropical crops.  Cambridge University Press, New York. 607 pp.

PPQ. 2018.  DEEP report for Pseudocercospora theae (Cavara) Deighton (Mycosphaerellaceae: Capnodiales) – Bird’s eye spot. United States Department of Agriculture, Animal and Plant Health Inspection Service, Plant Protection and Quarantine (PPQ), Raleigh, NC. 4 pp.

USDA PCIT.  2017.  USDA Phytosanitary Certificate Issuance & Tracking System. Retrieved March 21, 2018. 6:36:50 pm CDT.  https://pcit.aphis.usda.gov/PExD/faces/ReportHarmOrgs.jsp.


Responsible Party:

John J. Chitambar, Primary Plant Pathologist/Nematologist, California Department of Food and Agriculture, 3294 Meadowview Road, Sacramento, CA 95832. Phone: 916-262-1110, plant.health[@]cdfa.ca.gov.


Comment Period:* CLOSED

4/6/18 – 5/21/18


*NOTE:

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


Comment Format:

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

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

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

♦  Comments may not be posted if they:

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

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

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

Violates agency regulations prohibiting workplace violence, including threats.

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

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


Pest Rating: C

 


Posted by ls 

Colletotrichum henanense

California Pest Rating for
Colletotrichum henanense F. Liu & L. Cai 2015
Pest Rating: B

 


PEST RATING PROFILE

Initiating Event:  

On October 12, 2017, the California Dog Team a shipment of nuts of Castanea sativa (European chestnut) at a parcel distribution facility in Alameda County.  The shipment had originated in Indiana and was destined to a private citizen in Contra Costa County.  A sample of nuts were collected by Alameda County Agricultural officials, and sent to the CDFA Plant Diagnostics Branch for Diagnosis.  Suzanne Latham, CDFA plant pathologist detected the pathogen, Colletotrichum henanense in culture from the nuts. The identity of the associated pathogen was later confirmed by USDA National Identification Services at Beltsville, Maryland, and marked the first domestic detection of C. henanense in the USA.  Consequent to the California detection, all infected plant materials were destroyed. The risk of infestation of C. henanense in California is evaluated and a permanent rating is proposed.

History & Status:

Background:  Colletotrichum henanense is a distinct fungus species belonging to the vastly morphological and physiological variable C. gloeosporioides and is genetically identified from other species of the complex.  The species was originally described in 2015 from tea plants (Camelia sinensis) and Japanese thistle (Cirsium japonicum) in Xinyang, Henan Province, and Beijing, China respectively (Liu et al., 2015).  The pathogen causes anthracnose disease in its host plants.  Camellia species were affected by anthracnose disease in China where the plant species are used as in production of edible oil, processed tea and as ornamentals (Li et al., 2018; Liu et al., 2015).  The pathogen has only been reported from China until its 2017 detection in the California.

Symptoms: Generally, Colletotrichum-infected host plants exhibit symptoms of anthracnose which include dark brown leaf, stem and fruit spots and wilting of leaves which often result in dieback and reduction in plant quality.

HostsCamellia sinensis (tea tree), C. oleifera (tea-oil tree.  Theaceae); Cirsium japonicum (Japanese thistle.  Asteraceae) (De Silva et al., 2017; Li et al., 2018; Liu et al., 2015).  The detection of Colletotrichum henanense in Castanea sativa (European chestnut) is included here (see: Initiating Event).

Symptoms: Colletotrichum henanense causes leaf spot symptoms. Leaf spots or lesions in tea-oil tree are semicircular or half-oval, brown to black with greyish-white centers.  Severely infected leaves wither and drop (Li et al., 2018).

Disease Cycle: It is likely that Colletotrichum henanense has a similar life cycle to that of other Colletotrichum species and survives between crops during winter as mycelium on plant residue in soil, on infected plants, and on seeds.  During active growth, the pathogen produces masses of hyphae (stromata) which bear conidiophores, on the plant surface. Conidia (spores) are produced at the tips of the conidiophores and disseminated by wind, rain, cultivation tools, equipment, and field workers.   Conidia are transmitted to host plants.  Humid, wet, rainy weather is necessary for infection to occur.  These requirements may limit the occurrence of the pathogen in California fields and subsequently, the pathogen may be more of a problem under controlled environments of greenhouses.  Conidia germinate, penetrate host tissue by means of specialized hyphae (appresoria) and invade host tissue.

Transmission: Wind, wind-driven rain, cultivation tools, and human contact.

Damage Potential:  In China, 40% of tea-oil tree yield loss has been suggested (Li et al., 2018).  A 42.5% incidence of anthracnose disease caused by C. henanense was observed in 85 of 200 young tea-oil plants grown in a nursery in Kunming, Yunnan Province, China (Li et al., 2018).  Generally, anthracnose disease can result in reduced plant quality and growth, and marketability.  Nursery productions of Camellia and chestnut are particularly at risk as nursery conditions are often conducive to infection by Colletotrichum species.  In open fields, disease development may be sporadic as it is affected by levels of pathogen inoculum and environmental conditions.

Worldwide Distribution: Asia: China; North America: USA (De Silva et al., 2017; Li et al., 2018; Liu et al., 2015).

Official Control: None reported.

California Distribution Colletotrichum henanense is not established in California (see “Initiating Event”).

California InterceptionsThe risk Colletotrichum henanense would pose to California is evaluated below.

Consequences of Introduction:

1) Climate/Host Interaction: Like other species of Colletotrichum henanense requires humid, wet, rainy weather for conidia to infect host plants. This environmental requirement and narrow host range may limit the ability of the pathogen to fully establish and spread under dry field conditions.

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: Presently, the host range is limited to Camellia sinensis, C. oleifera, Cirsium japonicum, and Castanea sativa.

Evaluate the host range of the pest.

Score: 1

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: Colletotrichum henanense has high reproductive potential and conidia are produced successively.  They are transmitted by wind, wind-driven rain, cultivation tools, and human contact, however, conidial germination and plant infection require long, wet periods.

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: Anthracnose-infected chestnut and camellia plants may result in lower crop value and market loss.  Nursery productions of Camellia and chestnut are particularly at risk as nursery conditions are often conducive to infection by Colletotrichum  In open fields, disease development may be sporadic as it is affected by levels of pathogen inoculum and environmental conditions. Its economic impact is evaluated as a Medium risk.

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

Score: B, C

A. The pest could lower crop yield.

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

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

D. The pest could negatively change normal cultural practices.

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

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

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

Economic Impact Score: 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: Chestnut trees cultivated and growing in open environments in California are not expected to be significantly affected by Colletotrichum henanense due to the high moisture conditions required for the development of the pathogen.  However, under humid and moist environments, the pathogen may be more of a problem particularly in ornamental plantings of Camellia in home/urban and private/public settings.

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

Environmental Impact: E

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

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

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

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

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

Environmental Impact Score: 2

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

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

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

Consequences of Introduction to California for Colletotrichum henanense10

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: 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.

 Evaluation is ‘Not Established’

 Score (0). Colletotrichum henanense is not known to be established in California and is known only from its detected in an intercepted shipment of chestnut.

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: (Score)

Final Score:  Score of Consequences of Introduction – Score of Post Entry Distribution and Survey Information = 10.

Uncertainty:

None.

Conclusion and Rating Justification:

Based on the evidence provided above the proposed rating for the anthracnose pathogen, Colletotrichum henanense, is B.


References:

 De Silva, D. D., P. K. Ades, P. W. Crous and P. W. J. Taylor.  2017.  Colletotrichum species associated with chili anthracnose in Australia.  Plant Pathology 66 (2): 254-267.

Farr, D. F., and A. Y. Rossman. Fungal Databases, U.S. National Fungus Collections, ARS, USDA. Retrieved March 16, 2018, from https://nt.ars-grin.gov/fungaldatabases/

Li, H., G. Y. Zhou, X. Y. Qi and S. Q. Jiang.  2018.  First report of Colletotrichum henanense causing anthracnose on tea-oil trees in China.  Plant Disease “First Look” paper, accepted for publication, posted 01/03/2018. https://doi.org/10.1094/PDIS-08-17-1302-PDN 

Liu, F., Weir, B.S., Damm, U., Crous, P.W., Wang, Y., Liu, B., Wang, M., Zhang, M., and Cai, L. 2015. Unravelling Colletotrichum species associated with Camellia: employing ApMat and GS loci to resolve species in the C. gloeosporioides complex. Persoonia 35: 63-86.


Responsible Party:

John J. Chitambar, Primary Plant Pathologist/Nematologist, California Department of Food and Agriculture, 3294 Meadowview Road, Sacramento, CA 95832. Phone: 916-262-1110, plant.health[@]cdfa.ca.gov.


Comment Period:* CLOSED

4/6/18 – 5/21/18


*NOTE:

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


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Pest Rating: B

 


Posted by ls 

Marasmiellus Palmivorus

California Pest Rating for
Marasmiellus palmivorus (Sharples) Desjardin comb. prov.
Pest Rating: C

 


PEST RATING PROFILE

Initiating Event:   

None.  The risk of infestation of M. palmivorus in California evaluated and a permanent rating is herein proposed.

History & Status:

Background:   Marasmiellus palmivorus is a Basidiomycete fungus in the order Agaricales.  The species was described by Sharples in 1936, but, in the 1920s, was reported to have caused significant losses to oil palm and coconut in Malaysia 1920 (Pong et al., 2012).  In 1980, specimens of the fungus from coconut and oil palm were initially identified as Marasmiellus semiustus, a species that is generally regarded synonymous with M. palmivorus (CABI, 2018).  There has been confusion over the taxonomy of M. palmivorus and the species was previously attributed to the genus Marasmius (palmivorus).  However, Hemmes and Desjardin (2002) and Wilson and Desjardin (2005), in their taxonomic revision of the genus, regarded the genus Marasmius as a synonym of Marasmiellus until further DNA phylogenetic analysis is done to support its accurate identification (Pong et al., 2012).

Marasmiellus palmivorus can be saprophytic on a range of dead and dying plant material, or parasitic on tropical plants.  The species is reported to cause bunch rot disease on oil palm fruit, seeds, and seedlings in Malaysia (Almaliky et al., 2012; Pong et al., 2012), and is associated with leaf infection and bud rot of coconut, also causing embryo and shoot rot in germinating nuts and post-emergence damping off disease in Malaysia (Amaliky et al., 2013; CABI, 2018).  Synonymous species of M. palmivorus have also been recorded on pineapple causing trunk and root rot, and root rot of maize and sugarcane (CABI, 2018). In Hawaii, M. palmivorus was listed as a wood-rotting basidiomycete fungus of native and exotic plant species (Gilbertson et al., 2002).

In California, during March 2017, Marasmiellus palmivorus was detected on ginger flower stems from a shipment of ginger cut flowers that originated in Hawaii and was intercepted in Humboldt County by Humboldt County Agricultural officials. The pathogen was identified at the CDFA Plant Pathology Lab and was given a Q rating, which resulted in the destruction of the shipment.  The pathogen is not known to be established in California.

Disease Development: The fungus is normally saprophytic on decaying and dead materials.  It spreads to a new food source by growth of its hyphal strands or rhizomorphs and requires plenty of moisture for growth and development.  Not much is known of the biology of the fungus.  It is presumed that the fungus becomes parasitic once it has attained a certain inoculum level as infection by a small amount of spores or mycelium is unlikely (Turner, 1981 in CABI, 2018).

Dispersal and spread: Infected plants including flowers, fruits, leaves, roots, stems, true seeds, wood, contaminated coconut seed-nuts, plant decaying and dead materials, windblown rain, water-splash, air-currents (CABI, 2018).

Hosts: Ananas comosus (pineapple), Alpini purpurata (red ginger), Cocos nucifera (coconut), Elaeis guineensis (African oil palm), Etlingera elatior (torch ginger), Hevea brasiliensis (rubber), Musa x paradisiaca (plantain), Zingiber officinale (ginger) (Almaliky et al., 2012, 2013; CABI, 2017; Farr & Rossman, 2017; Gilbertson et al., 2002).

Symptoms:  Marasmiellus palmivorus causes bunch rot disease of oil palm in Malaysia.  In pathogenicity tests conducted by Almaliky et al. (2012), symptoms in fruit included a wet, discolored soft rot that extended upward to the tip of the fruit; infected seeds showed pre-emergence damping off consisting of seed decay, reddish-brown discoloration of shoots and radicles, failure to germinate, and post-emergence damping off; infected seedling initially showed chlorosis that turn brown to black rot lesions on the base of lower leaves, and roots were usually soft, rotten, water-soaked and dark brown or black in color with white mycelia covering the roots and crowns partially. Seedlings reared in a greenhouse developed root and crown rot and leaf blight.  Initial necrosis at the bases of leaves subsequently caused extensive discoloration, softening, rapid drying and wilting of leaves.  Rotting of seedlings initiated near the soil line and moved downwards and upwards resulting in parts of stems and base of leaves turning brown to black in color.  .  Dense white mycelia were formed on the lower stem of base of seedlings.  Basidiocarps (mushroom-like fruiting bodies) were formed at the base of seedlings near the crown.  The fungus also caused post-emergence damping off on coconut seedlings in Malaysia (Almaliky et al., 2013).  The researchers also showed that isolates from coconut were pathogenic to oil palm.

Damage Potential: In California, certain hosts, such as, ginger and plantain that are grown as ornamental plants by nurseries, small businesses, hobbyists, and private residents may be affected by the fungus if it were able to establish within high moisture environments.    

Worldwide Distribution:  Africa: Congo Democratic Republic, Nigeria; Asia: Brunei Darussalam, India (Andaman and Nicobar Islands), Indonesia, Malaysia; Central America and Caribbean: Trinidad and Tobago, North America: USA (Hawaii), South America: Colombia; Oceania: Fiji, Papua New Guinea (CABI, 2017; Farr & Rossman, 2017; Gilbertson et al., 2002).

Official Control: Marasmiellus palmivorus is on the ‘Harmful Organism’ lists for Guatemala, Nicaragua, and Peru (USDA-PCIT, 2017).

California Distribution: Marasmiellus palmivorus has not been reported from California.

California Interceptions: To date, Marasmiellus palmivorus has been detected once in a single shipment of ginger cuttings that were shipped from Hawaii and intercepted in Humboldt County.

The risk Marasmiellus palmivorus would pose to California is evaluated below.

Consequences of Introduction: 

1) Climate/Host Interaction: Marasmiellus palmivorus requires high amounts of moisture to grow and develop. It may be able to establish only in very limited areas of the State, if at all.

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.

2) Known Pest Host Range: The host range is limited to some tropical plants that include, pineapple, African oil palm, coconut, plantain, rubber, and ginger.  It is also a saprophytic and feeds on dead and decaying material.  Presently, its pathogenicity has only been reported on coconut and Oil palm.

Evaluate the host range of the pest.

Score: 1

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: Infected plants including flowers, fruits, leaves, roots, stems, true seeds, wood, contaminated coconut seed-nuts, plant decaying and dead materials, windblown rain, water-splash, air-currents.

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: Potential losses to oil palm in Malaysia have only been reported.  Economic impact due to the fungus are largely not known.  Most hosts of the fungus are not commercially grown in California. Other hosts, such as, ginger and plantain that are grown as ornamental plants by nurseries may be affected by the fungus if it were able to establish within high moisture environments.

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

Economic Impact: B

A. The pest could lower crop yield.

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

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

D. The pest could negatively change normal cultural practices.

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

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

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

Economic Impact Score: 1

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

– Medium (2) causes 2 of these impacts.

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

5) Environmental Impact:  Under high moisture environments, Marasmiellus palmivorus may impact ornamental plantings of host plants in home/urban gardens.

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

Environmental Impact: E

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

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

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

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

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

Environmental Impact Score: 2

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

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

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

Consequences of Introduction to California for Marasmiellus palmivorus: Low (8)

Add up the total score and include it here.

Low = 5-8 points

-Medium = 9-12 points

-High = 13-15 points

6) Post Entry Distribution and Survey Information: 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.

Evaluation is ‘Not established’ in California.

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: (Score)

Final Score:  Score of Consequences of Introduction – Score of Post Entry Distribution and Survey Information = 8

Uncertainty:

None.

Conclusion and Rating Justification:

Based on the evidence provided above the proposed rating for Marasmiellus palmivorus is C.


References:

Almaliky, B. S. A., M. A. Zainal Abidin, J. Kadir, and M. Y. Wong.  2012.  Pathogenicity of Marasmiellus palmivorus (Sharples) Desjardin comb. prov. on oil palm Elaeis guineensis.  Wulfenia 19: 1-17.

Almaliky, B. S. A., J. Kadir, M. Y. Wong, and M. A. Zainal Abidin.  2013.  First report of Marasmiellus palmivorus causing post-emergence damping off on coconut seedlings in Malaysia. Plant Disease 97: 143.

CABI, 2017.    Marasmius palmivorus (oil palm bunch rot) full datasheet.  Crop Protection Compendium.  http://www.cabi.org/cpc/datasheet/34926

Farr, D. F., and A. Y. Rossman.  2017.  Fungal Databases, U. S. National Fungus Collections, ARS, USDA. Retrieved April 27, 2017, from http://nt.ars-grin.gov/fungaldatabases/

Gilbertson, R. L., D. M. Bigelow, D. E. Hemmes, and D. E. Desjardin.  2002.  Annotated check list of wood-rotting Basidiomycetes of Hawai’i.  Mycotaxon 82: 215-239

Pong, V. M., M. A. Zainal Abidin, B. S. A. Almaliky, J. Kadir, and M. Y. Wong.  2012.  Isolation, fruiting and pathogenicity of Marasmiellus palmivorus (Sharples) Desjardin (comb.prov.) in oil palm plantations in West Malaysia.  Pertanika Tropical Agricultural Science 35 (S): 38-48.

USDA PCIT.  2017.  USDA Phytosanitary Certificate Issuance & Tracking System. April 26, 2017, 5:04:18 pm CDT.  https://pcit.aphis.usda.gov/PExD/faces/ReportHarmOrgs.jsp.


Responsible Party:

John J. Chitambar, Primary Plant Pathologist/Nematologist, California Department of Food and Agriculture, 3294 Meadowview Road, Sacramento, CA 95832. Phone: 916-262-1110, plant.health[@]cdfa.ca.gov.


Comment Period:* CLOSED

1/26/18 – 3/12/18


*NOTE:

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


Comment Format:

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

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

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

♦  Comments may not be posted if they:

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

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

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

Violates agency regulations prohibiting workplace violence, including threats.

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

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


Pest Rating: C

 


Posted by ls

Diaporthe pseudophoenicicola R. R. Gomes, C. Glienke & Crous 2013

California Pest Rating for
Diaporthe pseudophoenicicola R. R. Gomes, C. Glienke & Crous 2013
Pest Rating: C

 


PEST RATING PROFILE
Initiating Event:

On June 15, 2017, a shipment of an unknown plant, exhibiting symptoms of leaf spotting and destined to a commercial florist in Los Angeles County, was intercepted by the CDFA Dog Team in Los Angeles County.  The shipment had originated in Kilgore, Texas.  A sample of symptomatic leaves was submitted to the CDFA Plant Pathology Lab for disease diagnosis.  On July 7, 2017, Suzanne Latham, CDFA plant pathologist, detected the fungal pathogen, Diaporthe pseudophoenicicola, in culture and confirmed its identity by PCR testing, as the cause for the disease.  Later, on July 19, 2017, the same pathogen was detected in a date palm (Phoenix dactylifera) sample exhibiting decline and canker symptoms and collected from a tree located off Interstate 5 (I-5), in Orange County.  The sample was collected by Orange County Agricultural officials and sent to the CDFA Plant Pathology Lab for diagnosis.  Suzanne Latham detected D. pseudophoenicicola in culture and confirmed its identity by multi-locus sequencing.  Later, the identity of the pathogen was also confirmed by the USDA APHIS Mycology and Nematology Genetic Diversity and Biology Laboratory at Beltsville, Maryland (Kennedy, 2017).   The current status and rating of D. pseudophoenicicola in California is assessed here and a permanent rating is proposed.

History & Status:

Background:  Diaporthe pseudophoenicicola is a fungal plant pathogen belonging to the order Diaporthales.  The species was named after its morphological similarity to Diaporthe phoenicicola, which was originally isolated from dead leaves of Mangifera indica in Pakistan, however, later reported to differ morphologically from D. phoenicicola (Gomes et al., 2013).  Diaporthe pseudophoenicicola is the sexual state of the pathogen, whereas, the asexual state belongs to the genus Phomopsis.  Presently, D. pseudophoenicicola has only been reported from China, Iraq, and Spain (Farr & Rossman, 2017; Gomes, et al., 2013).

The asexual state of the fungal pathogen has been detected in California prior to the 2017 detection.  In 2007, during a CDFA survey for palm wilt in Southern California, 16 detections were made of unidentified Phomopsis sp. on Phoenix canariensis, P. dactylifera, and P. reclinata in 10 counties.   Only recently, was the Phomopsis species that was detected on P. dactylifera in Riverside County, identified through DNA sequencing as P. pseudophoenicicola (syn. Diaporthe pseudophoenicicola), thereby, indicating that this pathogen has already been established in California for at least 10 years.  Complete identification of the remaining Phomopsis sp. is pending (personal communication: Suzanne Latham, CDFA).

Disease Development While specific information is lacking, it is likely that plant infection and disease development caused by Diaporthe pseudophoenicicola are similar to those caused by other species of Diaporthe occurring as plant pathogens, endophytes or saprobes.  The fungus produces ascospores (sexual spores) in perithecia (sexual fruiting bodies) and conidia (asexual spores) in pycnidia on dead twigs and leaves.  Conidia are the main inoculum causing primary and secondary infections and are spread to host plants by splashing rains.  Ascospores may be involved in long distance dispersal of the pathogen.  The fungus is likely to overwinter as mycelium and/or as conidia within pycnidia (Agrios, 2005).

Dispersal and spread: Windblown/splashing rain and irrigation water, pruning tools, possibly insects, and animals can spread fungal spores to non-infected plants.

Hosts: Mangifera indica (mango), Phoenix dactylifera (date palm), P. canariensis (Canary Island palm) (Farr & Rossman, 2017; Gao et al., 2017; Gomes et al., 2013).

Symptoms:  Diaporthe pseudophoenicicola causes symptoms of dieback and canker in infected mango and date palm.  Dead tops of green leaves have been reported for date palms (Farr & Rossman, 2017; Gomes et al., 2013).

Damage Potential: Quantitative losses caused by Diaporthe pseudophoenicicola have not been reported. The pathogen causes dieback and cankers in mango and date palm.  Therefore, if left uncontrolled, infections may result in reduced fruit and plant production and marketability.  In California, nurseries and other growers of mango and date palms plants may be at risk of damage caused by this pathogen.

Worldwide Distribution: Asia: China, Iraq; Europe: Spain (Farr & Rossman, 2017; Gomes et al., 2013); North America: USA (California) (see: “Initiating Event”).

Official Control: No official control is reported for Diaporthe pseudophoenicicola or Diaporthe spp., however, Phomopsis spp. is presently on the ‘Harmful Organism List’ for French Polynesia (USDA PCIT, 2017).  Currently, D. pseudophoenicicola has a temporary Q rating in California.

California Distribution:  Los Angeles, Orange, and Riverside Counties.

California Interceptions: There has been only one interception.  On July 7, 2017, Diaporthe pseudophoenicicola was detected in a shipment of an unknown plant that originated in Texas (see: ‘Initiating Event’).

The risk Diaporthe pseudophoenicicola would pose to California is evaluated below.

Consequences of Introduction: 

1) Climate/Host Interaction: Mango and palm are the only known hosts and are grown in California.  Diaporthe pseudophoenicicola may be able to infect its hosts under wet conditions and is therefore, only likely to establish in very limited regions of the State where mango and palm are grown mainly Southern California.

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.

2) Known Pest Host Range: The host range of the pathogen is presently limited to Mangifera indica and Phoenix dactylifera.

Evaluate the host range of the pest.

Score: 1

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: Diaporthe pseudophoenicicola has high reproductive potential with an abundant production of spores, however, the spores are dependent on splashing water for dispersal.

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: Quantitative losses caused by Diaporthe pseudophoenicicola have not been reported. Under favorable wet conditions for spread and disease development the pathogen may cause dieback and cankers in mango and palm.  Therefore, if left uncontrolled, infections may result in reduced fruit and plant production and marketability.  In California, nurseries and other growers of mango and date palms plants may be at risk of damage caused by this pathogen.,

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

Economic Impact: A, B, C

A. The pest could lower crop yield.

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

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

D. The pest could negatively change normal cultural practices.

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

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

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

Economic Impact Score: 3

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

– Medium (2) causes 2 of these impacts.

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

5) Environmental Impact:  The pathogen may impact palms used as ornamental plantings in commercial and private environments.

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

Environmental Impact: E

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

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

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

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

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

Environmental Impact Score: 2

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

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

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

Consequences of Introduction to California for Diaporthe pseudophoenicicola: Medium (9)

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: 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.

Evaluation is Low.  The pathogen is already established in at least three counties in Southern California.

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

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

Final Score:  Score of Consequences of Introduction – Score of Post Entry Distribution and Survey Information = 8

Uncertainty:  

Identification of Phomopsis sp. (asexual state of Diaporthe) detected during the 2007 CDFA survey, is pending.  Positive identification may provide new information on the distribution and hosts of D. pseudophoenicicola in California, while further stabilizing its currently proposed rating.

Conclusion and Rating Justification:

Based on the evidence provided above the proposed rating for Diaporthe pseudophoenicicola is C.


References:

Agrios, G. N.  2005.  Plant Pathology Fifth Edition.  Elsevier Academic Press.  922 p.

Farr, D. F., and A. Y. Rossman.  2017.  Fungal Databases, U. S. National Fungus Collections, ARS, USDA. Retrieved September 20, 2017, from http://nt.ars-grin.gov/fungaldatabases/

Gao, Y., F. Liu, W. J. Duan, P. W. Crous, and L. Cai.  2017.  Diaporthe is paraphyletic. IMA Fungus 8(1): 153-187.

Gomes, R.R., C. Glienke, S. I. R. Videira, L. Lombard, J. Z. Groenewald, and P. W. Crous.  2013.  Diaporthe: a genus of endophytic, saprobic and plant pathogenic fungi. Persoonia 31: 1-41.

Kennedy, A. H.  2017.  Email from A. H. Kennedy, Molecular Biologist, USDA APHIS Mycology and Nematology Genetic Diversity and Biology Laboratory, Beltsville, Maryland, to Suzanne Latham, Plant Pathologist, CDFA Plant Pest Diagnostics Branch, dated September 01, 2017, 5:14 am.

USDA PCIT.  2017.  USDA Phytosanitary Certificate Issuance & Tracking System. Sept. 20, 2017, 2:11:43 pm CDT.  https://pcit.aphis.usda.gov/PExD/faces/ReportHarmOrgs.jsp.


Responsible Party:

John J. Chitambar, Primary Plant Pathologist/Nematologist, California Department of Food and Agriculture, 3294 Meadowview Road, Sacramento, CA 95832. Phone: 916-262-1110, plant.health[@]cdfa.ca.gov.


Comment Period:* CLOSED

12/29/17 – 2/12/18


*NOTE:

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


Comment Format:

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

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

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

♦  Comments may not be posted if they:

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

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

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

Violates agency regulations prohibiting workplace violence, including threats.

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

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


Pest Rating: C


Posted by ls