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Published Date: 2012-10-19 09:36:25
Subject: PRO/PL> Common scab, kinnow mandarin - Pakistan
Archive Number: 20121019.1351834

COMMON SCAB, KINNOW MANDARIN - PAKISTAN
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International Society for Infectious Diseases
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Date: Mon 8 Oct 2012
Source: FreshPlaza [edited]
http://www.freshplaza.com/news_detail.asp?id=101628

Urgent action called for against kinnow disease
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Kinnow [mandarin] growers have appealed to the Horticulture Board of Pakistan to take urgent action over an outbreak of scab affecting the fruit. Farmers Associates Pakistan said: "Last year [2011], export orders were cancelled because of the disease in the orchards and now once again there is a need for sprays as the disease has returned."

Harvest Tradings said: "This disease came due to extra moisture in the orchards. Farmers are advised to use sprays effectively and timely from now."

Indonesia and India have been added as new markets for the coming [2012] season.

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[Common citrus scab (or sour orange scab) is caused by the fungus _Elsinoe fawcettii_. It is a serious problem on susceptible varieties of, for example, sour orange, lemons (including rough lemon rootstocks), grapefruit, as well as a range of mandarin (including kinnow, _Citrus nobilis_ x _C. deliciosa_) and tangerine hybrids. Symptoms include raised pustules ('scabs') consisting of host and fungal tissues on leaves and fruit, as well as leaf distortion and corky growths on twigs. Affected fruit are no longer marketable.

Disease development is favoured by rain and humid conditions. Only young host tissue is susceptible to scab infection. 2 types of spores are produced which are spread by water splash or wind, respectively. Long distance spread and survival between seasons occurs mostly on infected plant material, including fruit. Disease management may include timely fungicide applications and cultural measures (such as reducing humidity in orchards).

The related _E. australis_ causes sweet orange scab, which differs in host range. Other species in the genus cause, for example, mango scab (_E. mangiferae_) and an anthracnose disease of grapevine (_E. ampelina_).

Kinnow mandarin in the region can also suffer severe yield losses due to ringspot disease (_Indian citrus ringspot virus_; see ProMED-mail post 20111216.3609).

Maps
Pakistan:
http://www.lib.utexas.edu/maps/middle_east_and_asia/pakistan_pol_2002.jpg and
http://healthmap.org/r/1iGJ

Pictures
Common scab symptoms on citrus leaves:
http://www.daff.qld.gov.au/images/Biosecurity_GeneralPlantHealthPestsDiseaseAndWeeds/CitrusCanker-CitrusScab-350.jpg and
http://www.apsnet.org/publications/imageresources/PublishingImages/1999/IW00011d.jpg
Common scab on citrus fruit:
http://www.dpi.nsw.gov.au/__data/assets/image/0016/137104/citrus-scab.jpg (lemon)
http://www.apsnet.org/publications/imageresources/PublishingImages/1999/IW00011c.jpg (sour orange),
http://3.bp.blogspot.com/-rdy-Ld_9dmw/UCentw1kFHI/AAAAAAAAAXg/6ceVKiGH0_o/s1600/Citrus+scab+on+mandarins.jpg (mandarin),
http://4.bp.blogspot.com/-7X74Fu4pM7I/T2-gMXxkGeI/AAAAAAAAAMA/rz4JcL0B1lA/s1600/1_tangerine_elisnoe_scab_foliar_fruit_1.JPG (tangerine), and
http://laplantpath.files.wordpress.com/2010/08/dscn2604cropped.jpg (satsuma)

Links
Additional news stories:
http://www.hortist.com/fruit/urgent-action-called-against-kinnow-disease-in-pakistan and
http://www.nation.com.pk/pakistan-news-newspaper-daily-english-online/business/02-Oct-2012/kinnow-produce-may-drop-after-disease
Information on citrus scab:
http://edis.ifas.ufl.edu/ch014,
http://www.idtools.org/id/citrus/diseases/factsheet.php?name=Citrus%20scab, and
http://www.ctahr.hawaii.edu/oc/freepubs/pdf/PD-60.pdf
Citrus scab management:
http://edis.ifas.ufl.edu/cg020
Comparison of common and sweet orange scab:
http://www.lsuagcenter.com/NR/rdonlyres/0AD09A71-2C58-40BB-88DB-3D75F2A82C56/74234/pub3169CitrusScabsHIGHRES.pdf
_E. fawcettii_ taxonomy:
http://www.indexfungorum.org/Names/NamesRecord.asp?RecordID=120451
Species and hybrids of citrus:
http://www.rbgsyd.nsw.gov.au/__data/assets/pdf_file/0019/73216/Tel7Mab167.pdf,
http://www.ars-grin.gov/cgi-bin/npgs/html/splist.pl?2640, and
http://www.buzzle.com/articles/hybrid-citrus-fruits.html. - Mod.DHA]

See Also