“B”
An pest of known economic or environmental detriment and, if present in California, it is of limited distribution. B-rated pests are eligible to enter the state if the receiving county has agreed to accept them. If found in the state, they are subject to state endorsed holding action and eradication only to provide for containment, as when found in a nursery. At the discretion of the individual county agricultural commissioner they are subject to eradication, containment, suppression, control, or other holding action.
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Posted by ka
Heather J. Scheck, CDFA Primary Plant Pathologist/Nematologist. 204 West Oak Ave, Lompoc, CA
93463. 805-736-8050. plant.health[@]cdfa.ca.gov.
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Posted by ka
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.
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Consequences of Introduction: 1. Climate/Host Interaction:
[Your comment that relates to “Climate/Host Interaction” here.]
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Posted by ls
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.
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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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Posted by ls
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.
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.
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:
Comments may be edited prior to posting to ensure they are entirely germane.
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Posted by ls
Karen Olmstead, Environmental Scientist; California Department of Food and Agriculture; 1220 N Street, Sacramento, CA 95814; Tel. (916) 403-6879; plant.health[@]cdfa.ca.gov
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
Updated on 7/12/2019 by ls
Karen Olmstead, Environmental Scientist; California Department of Food and Agriculture; 1220 N Street, Sacramento, CA 95814; Tel. (916) 403-6879; plant.health[@]cdfa.ca.gov
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
Updated by ls
John J. Chitambar, Primary Plant Pathologist/Nematologist, California Department of Food and Agriculture, Phone: 916-738-6693, plant.health[@]cdfa.ca.gov.
Updated on 7/10/2019 by ls
John J. Chitambar, Primary PlantPathologist/Nematologist, California Department of Food and Agriculture, plant.health[@]cdfa.ca.gov.
Updated on 7/10/2019 by ls
John J. Chitambar, Primary PlantPathologist/Nematologist, California Department of Food and Agriculture, plant.health[@]cdfa.ca.gov.
Updated on 7/10/2019 by ls
The risk of infestation of Citrus viroid V (CVd-V) in California is evaluated and a permanent rating is herein proposed.
Background: The origin of Citrus viroid V (CVd-V) is uncertain (Serra et al., 2008a). In a study in Spain on the response of Citrus species and citrus-related genera to viroid infections, Serra and other researchers (2008a) originally detected CVd-V in Atalantia citroides, a citrus relative plant propagated on rough lemon rootstock and graft-inoculated with artificial mixtures of different viroids. The viroid source was provided to them by a researcher at the University of California, Riverside and purified preparations were shown to be infectious in Etrog citron (Citrus medica), a classical indicator plant of citrus viroids. Subsequently, CVd-V was considered a new species of the genus Apscaviroid in the family Pospiviroidae (Serra et al., 2008a). Viroids are classified within two families: Pospiviroidae and Avsunviroidae. Citrus are natural hosts of several viroid species that belong to the family Pospiviroidae. Therefore, A. citroides was identified as an unusual viroid host since it was resistant to all previously known citrus viroids, yet capable of replicating CVd-V (Serra et al., 2008b). Infectious assays conducted by Sierra et al. (2008) showed that CVd-V in Etrog citron exhibited mild symptoms, however, co-infections with either Citrus bent leaf viroid (CBLVd) or Citrus dwarfing viroid (CDVd, previously Citrus viroid III), also belonging to the genus Apscaviroid, showed synergistic effects in contrast to single infections of CVd-V or the other two viroids, however, titers of the viroids remained the same in singly or doubly infected plants (Serra et al., 2008a).
While the origin of CVd-V is not known, Pakistan may be one of the geographic origins of the viroid (Serra et al., 2008a, b; Parakh et al., 2017). Serra et al. (2008a) suggested that the viroid was present, but overlooked or unnoticed, in field sources containing Hop stunt Viroid or Citrus dwarfing viroid – both of which have electrophoretic mobilities similar to CVd-V. CVd-V has been found with some variations in its nucleotide sequence, in several countries in Africa, Asia, Europe, and North America (see ‘Worldwide Distribution).
In June 2016, the Citrus Clonal Protection Program-National Clean Plant Network (CCPP-NCPN), University of California, Riverside, California detected Citrus Viroid V in citrus budwood samples submitted by the CDFA for virus and viroid testing under the mandatory California (CA 3701) Citrus Nursery Stock Pest Cleanliness Program. These budwood samples were taken from asymptomatic redblush grapefruit (Citrus paradisi) and variegated calamondin (C. madurensis) from a nursery in Tulare County. This find marked the natural occurrence of CVd-V in California and corroborated the earlier report of CVd-VCA variant in the State (Dang et al., 2018; Serra et al., 2008b).
Hosts: Citrus spp. including ‘Sanguinelli’, Salustiana’, and ‘Ricart navelina’ sweet oranges (Citrus x sinensis), ‘Oroval’ and ‘Hernandina clementines (C. clementina), ‘Fino’ and ‘Verna’ lemons (C. limon), ‘Sevilano’ and ‘Cajel’ sour orange (C. aurantium), ‘Clausellina’ satsuma (C. unshiu), Temple mandarin (C. temple), Tahiti lime, Palestine sweet lime (C. limettioides), calamondin (C. madurensis), ‘Calabria’ bergamot (C. bergamia), ‘Orlando’ tangelo (C. paradisi x C. tangerina), ‘Page’ mandarin [(C. paradisi x C. tangerina) x C. clementina], and ‘Nagami’ kumquat (Fortunella margarita), and Etrog citrus (Atlantia citroides) (Serra et al., 2008); ‘Shiranui’ [(C. unshiu x C. sinensis) x C. reticulata] (Ito and Ohta, 2010); ‘Moro blood’ sweet orange (Citrus x sinensis) (Bani Hashemian et al., 2013); redblush grapefruit (C. paradisi) (Dang et al., 2018).
Symptoms: Citrus viroid V induced mild characteristic symptoms of very small necrotic lesions and cracks, sometimes filled with gum, in the stems of the viroid indicator plant, Etrog citron. However, CVd-V reacted synergistically when Etrog citrus was co-infected with either citrus bent leaf viroid (CBLVd) or Citrus dwarfing viroid (CDVd), and showed severe stunting and epinasty with multiple lesions in the midvein. Plants co-infected with CBLVd and CVd-V exhibited severe stem cracking characteristic of CBLVd, but without gum exudates, whereas plant co-infected with CDVd showed necrotic lesions (Serra et al., 2008a). Symptoms induced by CVd-V alone in commercial species and varieties are presently not known since commercial trees may be co-infected with several viroids (Ito and Ohta, 2010; Serra et al., 2008a). Citrus viroid V may be present in asymptomatic citrus plant tissue – as recently evidenced by its detection in asymptomatic budwood collected from Tulare County, California.
Damage Potential: The effect of CVd-V in commercial citrus rootstock-scion combinations, alone and in combination with other viroids, is yet unknown, however, Serra et al. (2008b) suggested that CVd-V could reduce tree size and yield as has been reported for clementine trees grafted on trifoliate orange co-infected with several viroids. Therefore, the need for nursery planting stock free of CVd-V is important.
Transmission: Similar to other citrus viroids, CVd-V is graft-transmitted and is spread mainly through the propagation of infested material.
Worldwide Distribution: Africa: Oman (Serra et al., 2008), Tunisia (Hamdi et al., 2015); Asia: China, Japan, Nepal, Pakistan (Cao et al., 2013), Iran (Bani Hashemian et al., 2010), Turkey (Önelge and Yurtmen, 2012); Europe: Spain (Serra et al., 2008); North America: USA (Serra et al., 2008).
Official Control: Citrus viroid V is a disease agent of concern that is tested for in the CDFA Citrus Nursery Stock Pest Cleanliness Program (3 CCR §§ 3701, et seq.).
California Distribution: Tulare County (Dang et al., 2018).
California Interceptions: None reported.
The risk Citrus viroid V would pose to California is evaluated below.
1) Climate/Host Interaction: Citrus viroid V is likely to establish within infested propagative citrus materials in all citrus-growing regions of California.
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) Known Pest Host Range: Citrus viroid V has a moderate host range that is limited to several species and varieties of Citrus.
Evaluate the host range of the pest.
Score: 2
– 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: Citrus viroid V replicates autonomously within infested plants and is spread mainly through the propagation and movement of infested planting materials to non-infested regions.
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 effect of CVd-V in commercial citrus rootstock-scion combinations, alone and in combination with other viroids, is yet unknown, however, it has been suggested by Serra et al. (2008b) that CVd-V could reduce tree size and yield.
Evaluate the economic impact of the pest to California using the criteria below.
Score: 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: It is probable that home, urban, public garden and landscape plantings of CVd-V-infested citrus plantings may be significantly impacted by the viroid singly or in combination with other viroids.
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.
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 of CVd-V to California = 12.
6) Post Entry Distribution and Survey Information: Evaluate the known distribution in California. Only official records identified by a taxonomic expert and supported by voucher specimens deposited in natural history collections should be considered. Pest incursions that have been eradicated, are under eradication, or have been delimited with no further detections should not be included. (Score)
-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.
Evaluation is Low (-1). Currently, Citrus viroid V has only been detected in a nursery in Tulare County.
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 = 11.
The effect of CVd-V in commercial citrus rootstock-scion combinations, alone and in combination with other viroids, is yet unknown.
Based on the evidence provided above the proposed rating for Citrus viroid V is B.
Bani Hashemian, SM, Taheri, H, Duran-Vila, N, and Serr, P. 2010. First report of Citrus viroid V in Moro blood sweet orange in Iran. Plant Disease 94: 129.
Cao, M. J., Liu, Y. Q., Wang, X. F., Yang, F. Y., and Zhou, C. Y. 2010. First report of Citrus bark cracking viroid and Citrus viroid V infecting Citrus in China. Plant Disease 94: 922. https://doi.org/10.1094/PDIS-94-7-0922C
Dang, T., Tan, S. H., Bodaghi, S., Greer, G., Lavagi, I., Osman, F., Ramirez, B., Kress, J., Goodson, T., Weber, K., Zhang, Y. P., Vidalakis, G. First report of Citrus Viroid V naturally infecting grapefruit and calamondin trees in California. Plant Disease, Posted online on August 10, 2018. https://doi.org/10.1094/PDIS-01-18-0100-PDN
Hamdi, I., Elleuch, A., Bessaies, N., Grubb, C. D., and Fakhfakh, H. 2015. First report of Citrus viroid V in North Africa. Journal of General Plant Pathology 81, 87
Ito, T., and Ohta, S. 2010. First report of Citrus viroid V in Japan. Journal of General Plant Pathology 76: 348-350.
Önelge, N., and Yurtmen, M. 2012. First report of Citrus viroid V in Turkey. Journal of Plant Patholology 94 (Suppl. 4), 88.
Parakh, D. B., Zhu, S., and Sano, T. 2017. Geographical distribution of viroids in South, Southeast, and East Asia. In: Apscaviroids Infecting Citrus Trees by Tessitori, M, Viroids and Satellites, Edited by Hadidi, A, Flores, R, Randles, JW, and Palukaitis, P, Academic Press Ltd-Elsevier Science Ltd, Pages 243-249
Serra, P., Barbosa, C. J, Daros, J. A., Flores, R., Duran-Vila, N. 2008a. Citrus viroid V: molecular characterization and synergistic interactions with other members of the genus Apscaviroid. Virology 370, 102112.
Serra, P., Eiras, M., Bani-Hashemian, S. M., Murcia, N., Kitajima, E.W., Daro`s, J. A., et al., 2008b. Citrus viroid V: occurrence, host range, diagnosis, and identification of new variants. Phytopathology 98, 11991204.
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.
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Posted by ls
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.
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.
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.
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.
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
None.
Based on the evidence provided above the proposed rating for Corynespora cassiicola is B.
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 Saintpaulia. In, 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.
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.
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