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
A ProMED-mail post
ProMED-mail is a program of the
International Society for Infectious Diseases
Date: Mon 8 Oct 2012
Source: FreshPlaza [edited]
Urgent action called for against kinnow disease
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 , 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  season.
[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).
Common scab symptoms on citrus leaves:
Common scab on citrus fruit:
http://www.apsnet.org/publications/imageresources/PublishingImages/1999/IW00011c.jpg (sour orange),
http://4.bp.blogspot.com/-7X74Fu4pM7I/T2-gMXxkGeI/AAAAAAAAAMA/rz4JcL0B1lA/s1600/1_tangerine_elisnoe_scab_foliar_fruit_1.JPG (tangerine), and
Additional news stories:
Information on citrus scab:
Citrus scab management:
Comparison of common and sweet orange scab:
_E. fawcettii_ taxonomy:
Species and hybrids of citrus:
http://www.buzzle.com/articles/hybrid-citrus-fruits.html. - Mod.DHA]