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Published Date: 2018-08-17 12:20:36
Subject: PRO/PL> Late blight, potato - Malawi: (DE)
Archive Number: 20180817.5971029
LATE BLIGHT, POTATO - MALAWI: (DEDZA)
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Date: Tue 14 Aug 2018
Source: Nyasa Times [edited]
https://www.nyasatimes.com/dedza-irish-potato-farmers-dealt-heavy-blow/


Dedza [district] potato farmers [are] reeling under heavy losses after their crop was devastated by late blight disease which drastically reduced the quality and quantity of their yield.

[A] research technician for International Potato Centre (CIP) in Dedza concurred with the farmers saying the just ended [2018] growing season has been bad for potato farming due to the disease. He said the situation was worsened by the fact that many farmers use poor quality seeds [tubers] for planting.

[Byline: Sellah Singini-Mana]

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ProMED-mail
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[Late blight of potato (PLB) and tomato is caused by the fungus-like organism (oomycete) _Phytophthora infestans_ and can cause 100 per cent crop loss. The pathogen can also affect some other solanaceous crops. In potato, it affects leaves as well as tubers; in tomato, it causes lesions and rotting of leaves, stems, and fruits. The disease is favoured by cool, moist conditions. It can spread rapidly within a crop and destroy it within a few days. Under favourable conditions, epidemics in tomatoes may be even more rapid than in potatoes.

The pathogen is spread by plant material (including potato seed tubers, tomato transplants, plant debris, volunteer crop plants), mechanical means (including human and insect activities), wind, and water. Disease management requires an integrated approach and may include removal of pathogen reservoirs, crop rotation, preventative fungicide treatments of planting material, and fungicide sprays of crops. Farm-saved or uncertified seed tubers have often been reported as sources of PLB outbreaks and may be what is referred to above as 'poor quality seeds'. Commercial crop cultivars vary in susceptibility to late blight. Development of resistant cultivars is being counteracted by the adaptability of the pathogen.

Certified clean planting stock and management strategies for fungicide resistance of the pathogen are considered vital to control late blight outbreaks. Seed tuber certification schemes have been set up in many countries. Considerable variation in aggressiveness between different pathogen strains has been observed, but more virulent strains with additional fungicide resistances and increased yield losses are emerging frequently. Late blight is considered an increasing problem worldwide.

Maps
Malawi:
http://nthambazale.com/wp-content/uploads/2009/05/malawi_map.gif and
http://healthmap.org/promed/p/16724
Malawi districts:
https://en.wikipedia.org/wiki/Districts_of_Malawi
Africa, overview:
http://www.worldatlas.com/webimage/countrys/africa/maps/africa.jpg

Pictures
Late blight on potato:
http://farm1.static.flickr.com/81/281344513_74bbffe5fe.jpg and
http://cdn.phys.org/newman/gfx/news/2013/keepingpacew.jpg (resistant vs. susceptible cultivars)
Late blight on tomato:
http://ipm.illinois.edu/ifvn/volume15/images/tomato_late_blight.jpg
Microscopy of PLB infected cells:
http://micro.magnet.fsu.edu/optics/olympusmicd/galleries/brightfield/images/potatoblight.jpg

Links
Information on late blight:
http://vegetablemdonline.ppath.cornell.edu/factsheets/Potato_LateBlt.htm,
http://www.apsnet.org/edcenter/intropp/lessons/fungi/Oomycetes/Pages/LateBlight.aspx, and
http://www.scri.ac.uk/research/pp/pestanddisease/blightepidemiologyandpopulationbiology
PLB disease cycle:
http://bit.ly/2lnDBQg
_P. infestans_ taxonomy:
http://www.indexfungorum.org/Names/NamesRecord.asp?RecordID=232148
Global Initiative on Late Blight:
https://research.cip.cgiar.org/confluence/display/GILBWEB/Home
- Mod.DHA]

See Also

Late blight, tomato - UK: new strain susp 20180611.5850443
Late blight, potato - India: strain Blue 13 20180418.5755980
Late blight, potato - Bangladesh: (RP) 20180110.5550872
2017
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Late blight & post harvest rot, potato - Ireland & UK (NI) 20171124.5462543
Late blight, potato - UK: strain Dark Green 37 20171029.5412307
Late blight, potato - Bhutan: (CK) 20170619.5114985
Late blight, potato - Bangladesh (02): (RP) 20170209.4825828
Late blight, potato - Bangladesh: (RS) 20170115.4767829
2016
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Late blight, potato - Uganda: (South West) 20160602.4260691
Late blight & undiagnosed virus, potato - Bangladesh: (RP) 20160121.3953451
2015
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Late blight, potato - Spain: strain Blue13 1st rept, new A1/A2 strains 20150317.3237610
Late blight, potato - Nepal: (DN) 20150128.3127014
2014
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Late blight, potato - Nigeria, UK 20140611.2533396
Late blight, potato & tomato - Canada: strains 20140428.2434165
Late blight, potato - Bangladesh: (KH) 20140320.2345850
2013
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Late blight, tomato - Oman: (BS) 20130603.1752356
Yellow leaf curl & blights, tomato - Pakistan: (SD) 20130206.1531086
Late blight, potato: new strains threat 20130111.1492024
and additional items on late blight in the archives
.................................................sb/dha/mj/ml

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