{"id":1002,"date":"2015-06-01T07:00:57","date_gmt":"2015-06-01T14:00:57","guid":{"rendered":"http:\/\/blogs.cdfa.ca.gov\/Section3162\/?p=1002"},"modified":"2024-04-26T11:20:49","modified_gmt":"2024-04-26T18:20:49","slug":"xanthomonas-arboricola-pv-pruni-smith-vauterin-hoste-kersters-swings","status":"publish","type":"post","link":"https:\/\/blogs.cdfa.ca.gov\/Section3162\/?p=1002","title":{"rendered":"Xanthomonas arboricola pv. pruni (Smith) Vauterin, Hoste, Kersters & Swings"},"content":{"rendered":"
California Pest Rating for<\/strong><\/h5>\n
Xanthomonas arboricola<\/em><\/strong> pv. pruni<\/em> (Smith) Vauterin, Hoste, Kersters & Swings<\/strong><\/h5>\n
Pest Rating: B<\/strong><\/h5>\n
\n
PEST RATING PROFILE<\/strong><\/h5>\n
Initiating Event:<\/strong><\/h5>\n

In September 2013, CDFA plant pathologist, Luci Kumagai, identified Xanthomonas arboricola<\/em> pv. pruni<\/em> associated with symptomatic almond seedlings that were submitted by Sierra Gold Nursery in Sutter County to the CDFA Plant Pathology Laboratory.\u00a0 David Marion, CDFA environmental scientist, surveyed the nursery shade house where the trees were housed and determined that only Monterey Almond trees exhibited symptoms of bacterial canker.\u00a0 Subsequently, in line with CDFA\u2019s current Q rating of X. arboricola<\/em> pv. pruni<\/em> and \u2018Nursery Standard of Cleanliness\u2019, the lot of affected almond trees was destroyed and other Prunus<\/em> spp. in the nursery were protected from further potential infection. Near about that time, the pathogen was found in commercial almond orchards in a few counties in northern California, thereby marking its first non-official detection in the State.\u00a0 The detection of the associated disease was reported by the University of California Cooperative Extension Farm Advisor for Stanislaus County.\u00a0 In view of the recent finds, the current temporary rating is herein assessed for the proposal of a permanent rating.<\/p>\n

History & Status:<\/strong><\/h5>\n

Background<\/strong><\/span>: \u00a0Xanthomonas arboricola<\/em> pv. pruni<\/em> is a bacterial pathogen that attacks only Prunus<\/em> spp. causing disease commonly known by various names: bacterial canker of stone fruit, bacterial leaf spot of stone fruit, bacterial shot-hole of stone fruit, and black spot of stone fruit.\u00a0 The bacterium belongs to the family Xanthomonadaceae of the order Xanthomonodales.\u00a0 No strains have been reported, however, difference in virulence to peach, plum and apricot have been noted (Du Plessis, 1988).\u00a0 The species was first described in North America (Michigan) in 1903 on Japanese plum, but it not clear if it spread from there throughout the world or if it naturally has a wide geographical range.\u00a0 In California, it is a relatively new disease of almonds (UCIPM, 2013).<\/p>\n

Disease cycle:\u00a0 On Prunus<\/em> species, the pathogen overwinters in plant tissues such as buds, protected areas (cracks in the bark), and in leaf scars. On almonds it overwinters on fruit mummies and twig cankers.\u00a0 On plum and apricot, cankers formed during the preceding season continue to develop in spring and provide a source of inoculum.\u00a0 During late winter as temperatures warm, peach leaf and flower buds swell, and as new tissue growth initiates, bacteria multiply and cause the epidermis to rupture, forming a lesion or spring canker. \u00a0Bacteria are spread from cankers or mummified fruit to newly emerging leaves by dripping dew and splashing and\/or wind-blown rain.\u00a0 Infection takes place through natural openings or wounds.\u00a0 High moisture conditions favor leaf and fruit infections.\u00a0 Severe infection is favored by warm temperatures (19-28\u00b0C), light frequent rainfall and fairly heavy winds and dew.\u00a0 Following foliar infection, cankers develop in the green shoot tissue, but usually become sealed off by formation of a periderm barrier layer.\u00a0 Also, cankers tend to dry out during the summer months thereby reducing viability of bacteria.\u00a0 For that reason, twig cankers produced in plum and peach during the summer are not considered important overwintering sites or sources of inoculum for spring infections.\u00a0 Generally, late shoot infections that occur just before leaf fall in autumn provide the primary inoculum source for the following spring (CABI, 2014; UCIPM, 2013).<\/p>\n

Hosts<\/em>:\u00a0 Xanthomonas arboricola<\/em> pv. pruni<\/em> attacks only Prunus<\/em> species, in particular fruit crops such as almonds, peaches, cherries, plums, apricots, P. salicina <\/em>(Chinese\/Japanese plum), and ornamental species of Prunus<\/em> including P<\/em>. davidiana<\/em> (Chinese wild peach), Japanese apricot (P. mume<\/em>), and P<\/em>. laurocerasus<\/em> (cherry laurel).\u00a0 Generally, species of the Sino-Japanese group (P. japonica<\/em> and P. salicina<\/em>) are more susceptible than European plums (CABI, 2014; EPPO, 2013)<\/p>\n

Symptoms<\/em>: Symptoms may vary depending on the infected plant host and plant part.<\/p>\n

On peach leaves, infection is first apparent on the lower leaf surface as small, pale green to yellow, circular or irregular areas with a light tan center. These spots become apparent on the upper surface as they enlarge, becoming angular and darken to deep-purple, brown or black.\u00a0 Tissue immediately surrounding the diseased spots becomes yellow.\u00a0 The spots may darken before they drop out giving a shot-hole appearance. Usually, spots are concentrated toward the leaf tip as bacteria accumulate in that area with droplets of rain or dew. Bacterial ooze may exude from the spots.\u00a0 In severe infections defoliation may occur.\u00a0 On peach fruit, small, sunken circular spots with frequently water-soaked margins or light green halos appear on the surface. Pitting and cracking occur near the spots as the fruit enlarges.\u00a0 Gum may exude from bacterial wounds, especially after heavy rains.\u00a0 Spring cankers appear on the top part of overwintering twigs before green shoots are produced.\u00a0 These cankers initiate as small, water-soaked slightly darkened superficial blisters that extend 1-10 cm along the length of the twig or girdle it causing tip death or \u201cblack tip injury\u2019.\u00a0 The area below the dead tip harbors the bacteria.\u00a0 Twigs that get infected late in season result in \u2018summer cankers\u2019 which are dark purple spots surrounding lenticels that later dry out and become limited, dark, sunken, circular to elliptical lesions.<\/p>\n

On plum leaves: the shot-hole effect is more pronounced than on peach leaves.\u00a0 On plum fruit symptoms vary from large sunken, black lesions to small pit-like lesions.\u00a0 On plum and apricot, twig cankers are perennial developing on 2-3 year old twigs.\u00a0 As a result, deep-seated cankers are formed in the inner bark thereby deforming and killing twigs.<\/p>\n

On cherry leaves symptoms develop similar to peach but are rarely of importance.\u00a0 Fruit may be distorted and bacteria usually internally inhabit fruit pulp.<\/p>\n

On almond:\u00a0 In California, damage has been predominant on the \u2018Fritz\u2019 variety however similar damage has been observed by researchers on \u2018Monterey\u2019, \u2018Padre\u2019, and \u2018Nonpareil\u2019 varieties (Holtz et al<\/em>., 2013).\u00a0 Symptoms on leaves, twigs and fruit are similar to those produced on peach.\u00a0 Symptoms on infected almond nuts include the production of amber colored gum from spots on the hull which internally reveals a lesion. Lesions may enlarge, become sunken and orange in color, or exude an orange slime.\u00a0 Furthermore, infected nuts may stick on spurs and be close to mummified, lesion nuts of the previous year.\u00a0\u00a0\u00a0 Leaves may have spots, turn yellow and drop prematurely.\u00a0 Twigs may have lesions or cankers.<\/p>\n

Damage Potential<\/em>:\u00a0 The pathogen is capable of causing severe defoliation thereby weakening trees.\u00a0 The leader (i.e., the vertical stem at the top of the trunk) dies and fruit is reduced in size and often not marketable.\u00a0 Serious losses in peach (25-75%), plum and apricot production are reported from Australia, New Zealand, and the USA (CABI, 2014; EPPO, 2014).\u00a0 Damage to stone fruit is more severe where the latter are grown in light, sandy soils than in heavier soils (UCIPM, 2013).<\/p>\n

Transmission<\/em>:\u00a0 Local spread of the bacterial pathogen from cankers and mummified fruit is limited and dependent on dripping dew and splashing and\/or wind-blown rain.\u00a0 Long distance spread, as in international trade, is through infected plantings, budwood, and fruit (except seeds).<\/p>\n

Worldwide Distribution<\/strong><\/span>: Asia<\/em> (China, India, Iran, Japan, Korea DPR, Korea Republic, Lebanon, Pakistan, Saudi Arabia, Taiwan, Tajikistan); Africa<\/em> (South Africa, Zimbabwe); Europe<\/em> (Bulgaria, France, Italy, Moldova, Montenegro, Netherlands, Romania, Russia (Far East, Southern), Slovenia, Spain, Switzerland, Ukraine); North America <\/em>(Bermuda, Canada, Mexico, USA); South America <\/em>(Argentina, Brazil, Uruguay); Oceania<\/em> (Australia, New Zealand).<\/p>\n

In the USA it is present in Alabama, Arkansas, California, Connecticut, Florida, Georgia, Idaho, Kentucky, Louisiana, Maryland, Michigan, Mississippi, Missouri, New Jersey, New York, North Carolina, Oregon, Pennsylvania, South Carolina, and Texas.<\/p>\n

Official Control<\/strong><\/span>: Ten countries list X. arboricola<\/em> pv. pruni<\/em> on their \u201cHarmful Organism Lists\u2019 namely, Canada, Chile, Ecuador, Israel, Madagascar, Mexico, Morocco, New Caledonia, Peru, and Turkey.\u00a0 Whereas, 41 countries worldwide list X. campestris<\/em> pv. pruni<\/em> (synonym of X. arboricola<\/em> pv. pruni<\/em>) on their lists (USDA PCIT, 2014).\u00a0 Xathomonas arboricola<\/em> pv. pruni<\/em> is listed as an A2 quarantine pest by EPPO and of little economic importance in EPPO countries where it is present.\u00a0 Also, it is of quarantine significance for the Inter-African Phytosanitary Council\/IAPSC (EPPO, 2014).<\/p>\n

California Distribution<\/strong><\/span>:\u00a0 The bacterial spot pathogen is relatively in California.\u00a0 It has been found on almonds (mainly Fritz cultivar), in Colusa, Merced, Stanislaus, and San Joaquin Counties, as well as sweet cherry and other stone fruit crops in San Joaquin and Stanislaus Counties (UCIPM, 2013).<\/p>\n

California Interceptions<\/strong><\/span>:\u00a0 The pathogen was recently intercepted in a nursery in Sutter County.\u00a0 The plants were destroyed (see \u2018Initiating event\u2019.)<\/p>\n

The risk Xanthomonas arboricola<\/em> pv. pruni<\/em> would pose to California is evaluated below.<\/p>\n

Consequences of Introduction:\u00a0<\/strong><\/h5>\n

1) \u00a0Climate\/Host Interaction:<\/strong> Evaluate if the pest would have suitable hosts and climate to establish in California. Score:<\/p>\n

– Low (1) not likely to establish in California; or likely to establish in very limited areas
\n\u2013 Medium (2)<\/strong> may be able to establish in a larger but limited part of California<\/span>
\n\u2013 High (3) <\/span>likely to establish a widespread distribution in California.<\/p>\n

Risk is High (2)<\/span>:\u00a0 <\/em><\/strong>\u00a0<\/strong>The pathogen is limited to high moisture and warm temperature conditions and regions for establishment.<\/em><\/p>\n

2) \u00a0Known Pest Host Range:<\/strong> Evaluate the host range of the pest:<\/p>\n

– Low (1) has a very limited host range
\n\u2013\u00a0Medium (2)<\/strong> has a moderate host range<\/span>
\n\u2013 High (3) has a wide host range.<\/p>\n

Risk is Medium (2)<\/span>: <\/em><\/strong>The host range is limited to <\/em>Prunus spp. stonefruit which is cultivated in vast acreage within California. \u00a0<\/em><\/p>\n

3) \u00a0Pest Dispersal Potential:<\/strong> Evaluate the dispersal potential of the pest:<\/p>\n

– Low (1) does not have high reproductive or dispersal potential
\n\u2013 Medium (2) has either high reproductive or dispersal potential
\n\u2013 High (3) <\/strong>has both high reproduction and dispersal potential.<\/span><\/p>\n

Risk is High (2)<\/span>:<\/em><\/strong> The pathogen increases and tends to cause infections in spring and its spread to non-infected tissue is dependent on warm temperatures and wet conditions brought about by wind-driven rainfall, water-splash and dripping dew.<\/em><\/p>\n

4) \u00a0Economic Impact:<\/strong> Evaluate the economic impact of the pest to California using these criteria:<\/p>\n

A. \u00a0 The pest could lower crop yield.
\nB. \u00a0 The pest could lower crop value (includes increasing crop production costs).
\nC. \u00a0 The pest could trigger the loss of markets (includes quarantines).
\nD. \u00a0 The pest could negatively change normal cultural practices.
\nE. \u00a0 The pest can vector, or is vectored, by another pestiferous organism.
\nF. \u00a0 The organism is injurious or poisonous to agriculturally important animals.
\nG. \u00a0 The organism can interfere with the delivery or supply of water for agricultural uses.<\/p>\n

– Low (1) causes 0 or 1 of these impacts
\n\u2013 Medium (2) causes 2 of these impacts
\n\u2013 High (3)<\/strong> causes 3 or more of these impacts.<\/span><\/p>\n

Risk is High (3)<\/span>: <\/em><\/strong>Infection of <\/em>Prunus spp. could lower crop yield and value thereby resulting in a loss of market.<\/em><\/p>\n

5) \u00a0Environmental Impact:<\/strong> Evaluate the environmental impact of the pest on California using these criteria:<\/p>\n

A. \u00a0 The pest could have a significant environmental impact such as lowering biodiversity, disrupting natural communities, or changing ecosystem processes.
\nB. \u00a0 The pest could directly affect threatened or endangered species.
\nC. \u00a0 The pest could impact threatened or endangered species by disrupting critical habitats.
\nD. \u00a0 The pest could trigger additional official or private treatment programs.
\nE. \u00a0 The pest significantly impacts cultural practices, home\/urban gardening or ornamental plantings.<\/p>\n

Score the pest for Environmental Impact:<\/p>\n

– Low (1) causes none of the above to occur
\n\u2013 Medium (2) causes one of the above to occur
\n\u2013 High (3)<\/strong> causes two or more of the above to occur.<\/span><\/p>\n

Risk is <\/em><\/strong><\/span>High (3)<\/span>:<\/em><\/strong> Infection of ornamental <\/em>Prunus species, in particular could impact residential and commercial cultivation of ornamental and fruit trees, requiring cultural practices to remove infected plant parts and mummified fruit.\u00a0 In addition, official and private treatment programs may be needed to manage the pathogen.<\/em><\/p>\n

Consequences of Introduction to California for Xanthomonas arboricola<\/em> pv. pruni<\/em>:<\/strong><\/h5>\n

Add up the total score and include it here. (Score)<\/p>\n

Low = 5-8 points
\nMedium<\/strong> = 9-12 points<\/span>
\nHigh = 13-15 points<\/p>\n

Total points obtained on evaluation of consequences of introduction to California = 12<\/strong><\/span><\/p>\n

6) \u00a0Post Entry Distribution and Survey Information<\/strong>: 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)<\/p>\n

-Not established (0) Pest never detected in California, or known only from incursions.
\n–Low (-1)<\/strong> Pest has a localized distribution in California, or is established in one suitable climate\/host area (region).<\/span>
\n-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.
\n-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.<\/p>\n

Evaluation Low (-1):<\/span> \u00a0<\/em><\/strong>Xanthomonas arboricola pv. <\/em>pruni has been detected on almond, sweet cherry and other stone fruit in four counties within the Central Valley of California.<\/em><\/p>\n

Final Score:<\/h5>\n

7) The final score is the consequences of introduction score minus the post entry distribution and survey information score: (Score)<\/p>\n

\u00a0Final Score: <\/em><\/strong><\/span>\u00a0Score of Consequences of Introduction \u2013 Score of Post Entry Distribution and Survey Information = 11<\/strong><\/span><\/em><\/p>\n

Uncertainty:<\/h5>\n

To date, Xanthomonas arboricola<\/em> pv. pruni<\/em> has been detected mainly in almond orchards in four California counties.\u00a0\u00a0 Targeted surveys for the detection of this relatively new pathogen may result in a wider distribution and range of host plants than currently known for the State.\u00a0 If that occurs, then a lower rating than that proposed here is probable.\u00a0 Therefore, diligent screenings and management of planting stock in nurseries will remain critical to mitigate risk of introduction of the pathogen to new, non-infected commercial production sites.<\/p>\n

Conclusion and Rating Justification:<\/h5>\n

Based on the evidence provided above the proposed rating for Xanthomonas arboricola<\/em> pv. pruni<\/em> is B.<\/strong><\/p>\n

References:<\/strong><\/h5>\n

C<\/strong>ABI.\u00a0 2014.\u00a0 Xanthomonas arboricola pv. pruni datasheet report.\u00a0 Crop Protection Compendium.\u00a0 www.cabi.org\/cpc\/<\/a><\/p>\n

D<\/strong>u Plessis, H. 1988.\u00a0 Differential virulence of Xanthomonas campestris<\/em> pv. pruni<\/em> for peach, plum, and apricot cultivars.\u00a0 Phytopathology, 78 (10):1312-1315.<\/p>\n

E<\/strong>PPO, 2014.\u00a0 Xanthomonas arboricola<\/em> pv. pruni<\/em> (XANTPR).\u00a0 PQR database.\u00a0 Paris, France:\u00a0 European and Mediterranean Plant Protection Organization.\u00a0 http:\/\/newpqr.eppo.int<\/a><\/p>\n

H<\/strong>oltz, B., D. Doll, R. Duncan, J. Edstrom, T. Michailides, and J. Adaskaveg.\u00a0 2013.\u00a0\u00a0 http:\/\/www.ipm.ucdavis.edu\/PDF\/MISC\/168605.pdf<\/a><\/p>\n

U<\/strong>CIPM.\u00a0 2013.\u00a0 Bacterial spot (Xanthomonas arboricola<\/em> pv. pruni<\/em>) University of California Agriculture & Natural Resources, UC IPM Online, Statewide Integrated Pest Management Program.\u00a0 http:\/\/www.ipm.ucdavis.edu\/EXOTIC\/bacterialspot.html<\/a><\/p>\n

U<\/strong>SDA PCIT.\u00a0 2014.\u00a0 USDA Phytosanitary Certificate Issuance and Tracking System.\u00a0 Phytosanitary Export Database.\u00a0 https:\/\/pcit.aphis.usda.gov\/PExD\/faces\/ReportHarmOrgs.jsp<\/a><\/p>\n

Responsible Party:<\/h5>\n

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.<\/p>\n

\n

PEST RATING: B<\/h3>\n
\n

Posted by ls<\/em><\/p>\n","protected":false},"excerpt":{"rendered":"

California Pest Rating for Xanthomonas arboricola pv. pruni (Smith) Vauterin, Hoste, Kersters & Swings Pest Rating: B PEST RATING PROFILE Initiating Event: In September 2013, CDFA plant pathologist, Luci Kumagai, identified Xanthomonas arboricola pv. pruni associated with symptomatic almond seedlings that were submitted by Sierra Gold Nursery in Sutter County to the CDFA Plant Pathology … Continue reading Xanthomonas arboricola pv. pruni (Smith) Vauterin, Hoste, Kersters & Swings<\/span> →<\/span><\/a><\/p>\n","protected":false},"author":1117,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":true,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":false},"version":2},"jetpack_post_was_ever_published":false},"categories":[9,4],"tags":[40,45,170],"class_list":["post-1002","post","type-post","status-publish","format-standard","hentry","category-bacteria","category-plant-pathology","tag-bacteria-2","tag-plant-pathogen","tag-xanthomonas-arboricola-pv-pruni"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"jetpack_shortlink":"https:\/\/wp.me\/p5l8vQ-ga","jetpack-related-posts":[{"id":13444,"url":"https:\/\/blogs.cdfa.ca.gov\/Section3162\/?p=13444","url_meta":{"origin":1002,"position":0},"title":"Xanthomonas arboricola pv. juglandis (Pierce 1901) Vauterin et al. 1995 Walnut blight","author":"Heather Martin","date":"October 25, 2024","format":false,"excerpt":"California Pest Rating Profile for Xanthomonas arboricola pv. juglandis (Pierce 1901) Vauterin et al. 1995 Walnut blightPest Rating:\u00a0C download pest rating profile *NOTE You must be registered and logged in to post a comment. 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