A ProMED-mail post <http://www.promedmail.org>
ProMED-mail is a program of the International Society for Infectious Diseases <http://www.isid.org>
Date: Tue 7 Apr 2020
Source: International Potato Centre (CIP) [edited] <https://cipotato.org/blog/mapping-bacterial-wilt-uganda/>
First documented in Uganda in 1958, bacterial wilt [BW] is widespread, limiting yields and degrading seed [tuber] quality. But little is known about the extent of the disease and the type of pathogen strains involved. BW is not always apparent: the harvest can look healthy, but will not be fit as seed [tubers]. "There has been no monitoring and documentation of BW in Uganda," said Kalpana Sharma, CIP. Many African countries do not have measures in place to prevent its spread [and] do not have certified seed systems.
[CIP] conducted a nationwide survey to chart the prevalence and spread of BW, as well as the type of pathogens present. The results confirmed that the disease was moving primarily through seed [tubers]. BW was present in 73% of ware potato farms and 50% of seed potato farms. The disease has moved from eastern and western regions to the northern region where potatoes have been more recently introduced.
"We have provided evidence about the types, presence and movement of BW, researchers and policy makers can use this to develop appropriate management strategies within [a] seed [tuber] regulatory framework,"
[said] Sharma. The completed study is being compared with the findings of a similar study in Ethiopia, Kenya and Rwanda. The next steps will be to scale this up into other countries, such as Tanzania and Malawi, to generate a BW regional map for improved collaboration across national borders.
--
Communicated by: ProMED-mail <promed@promedmail.org>
[Brown rot (also called bacterial wilt) of potato is caused by _Ralstonia solanacearum_ race 3 (biovar 2, adapted to cooler temperatures) or race 1 (prevalent in warmer areas). Yield losses are mostly caused by tuber rotting. The pathogen also causes bacterial wilt of tomato, a major disease of the crop, and it can also affect other solanaceous crops.
The bacteria are spread by mechanical means (including insect activities), contaminated equipment, infected plant material (including seed potatoes), soil and water. They can survive in soil on plant debris or roots of hosts. Some solanaceous weeds and unharvested potato plants may serve as pathogen reservoirs. Disease management is difficult, relying mostly on exclusion from new areas. Some cultural methods (such as crop rotation), control of pathogen reservoirs and phytosanitary measures (soil fumigation) may be used. Biological control is being investigated. Potato cultivars with levels of genetic resistance are available for certain growing conditions.
The source paper (see link below) reports that the strains identified in Uganda belonged to three phylotypes. Members of one of these was identified as playing an important epidemiological role, being disseminated via latently infected seed tubers.
Members of the _R. solanacearum_ species complex affect more than 200 plant species including many important crops. The various races and biovars are active under different climatic conditions and in different hosts.
Maps
Uganda:
<http://www.nationsonline.org/maps/uganda-political-map.jpg>
Africa (overview):
<http://www.lib.utexas.edu/maps/africa/africa_pol97.jpg>
Pictures
Potato brown rot symptoms:
<http://www.fsvps.ru/fsvps-docs/img/core/2014-4/mk4ymkuhfs.jpg>,
<http://plantpath.ifas.ufl.edu/rsol/images/Modules/Sptme1_BR.gif>,
<http://plantpath.ifas.ufl.edu/rsol/images/Modules/Sptme2_BR.gif>,
<https://projects.ncsu.edu/cals/course/pp728/Ralstonia/potato_field.gif>
and
<https://www.overtopinfo.com/wp-content/uploads/2019/09/Bacterial-Wilt-of-Potato.jpg>
Bacterial wilt symptoms on tomato plants:
<https://giantveggiegardener.files.wordpress.com/2011/03/bacterial-wilt-u-of-wisconsin.jpg>
and
<http://entoweb.okstate.edu/ddd/IMAGES/bactwilt.jpg>
Links
Original publication for the story above:
<https://apsjournals.apsnet.org/doi/full/10.1094/PHYTO-12-18-0476-R>
Information on brown rot of potato:
<https://planthealthportal.defra.gov.uk/assets/factsheets/brownrot.pdf>,
<http://www.plantmanagementnetwork.org/pub/php/review/2009/ralstonia/>,
<https://potatoes.ahdb.org.uk/media-gallery/detail/13214/2637> (with pictures), <http://agriculture.vic.gov.au/agriculture/pests-diseases-and-weeds/plant-diseases/vegetable/potato-diseases/potatoes-bacterial-wilt>,
<http://www.cabi.org/isc/datasheet/45009> and <https://plantpath.ifas.ufl.edu/rsol/Trainingmodules/BRPotato_Module.html>
Information on bacterial wilt of tomato:
<http://www.tomatodirt.com/bacterial-wilt.html> and <https://plantpath.ifas.ufl.edu/rsol/Trainingmodules/BWTomato_Module.html>
_R. solanacearum_, pathogen and disease information:
<https://gd.eppo.int/taxon/RALSSO> (with pictures), <http://www.cals.ncsu.edu/course/pp728/Ralstonia/Ralstonia_solanacearum.html>,
<http://www.oisat.org/pests/diseases/bacterial/bacterial_wilt.html>,
<https://gd.eppo.int/download/standard/145/pm7-021-2-en.pdf>,
<http://onlinelibrary.wiley.com/doi/10.1046/j.1364-3703.2002.00102.x/full>,
<http://iant.toulouse.inra.fr/bacteria/annotation/cgi/ralso.cgi> and <https://www.frontiersin.org/articles/10.3389/fpls.2014.00715/full>
Rs races and biovars:
<https://projects.ncsu.edu/cals/course/pp728/Ralstonia/Races_and_biovars_of_Ralstonia_solanacearum.html>
(overview) and
<https://www.researchgate.net/publication/326569728_Characterization_of_biovar_races_of_Ralstonia_solanacearum_the_incitant_of_bacterial_wilt_in_solanaceous_crops>
(tomato and other Solanaceae)
Description and taxonomy of _R. solanacearum_:
<http://www.uniprot.org/taxonomy/305>
- Mod.DHA]
[See Also:
Bacterial wilt, tomato - Ghana: (UE)
http://promedmail.org/post/20200123.6911226
2019
----
Potato diseases - Russia: survey
http://promedmail.org/post/20190606.6506616
2018
----
Wart & brown rot, potato - Georgia, Russia: interceptions
http://promedmail.org/post/20180327.5712463
2017
----
Brown rot, potato - Switzerland: alert
http://promedmail.org/post/20170227.4868480
Brown rot, potato - Poland
http://promedmail.org/post/20170213.4834454
Brown rot, potato - Chile: (AR,LR)
http://promedmail.org/post/20170120.4778242
2015
----
Bacterial wilt, tomato - Uganda: (QL)
http://promedmail.org/post/20150520.3373776
Brown rot, potato - India http://promedmail.org/post/20150514.3361262
Bacterial diseases, potato - Europe: 1st reports
http://promedmail.org/post/20150210.3157933
2014
----
Brown rot, potato - Russia: (PR) interceptions
http://promedmail.org/post/20140527.2500654
2013
----
Emerging crop diseases - Bolivia
http://promedmail.org/post/20130504.1690667
2012
----
Bacterial wilt, tomato - Kenya, Canada
http://promedmail.org/post/20120123.1018696
2011
----
Brown rot, potato - Russia: (KL) ex Egypt
http://promedmail.org/post/20110418.1208
2010
----
Bacterial wilt, tomato - Uganda, Nepal
http://promedmail.org/post/20101209.4386
Brown rot, potato - Lesotho: (MS, TT)
http://promedmail.org/post/20100221.0591
Bacterial wilt, eggplant - India: (KA) control
http://promedmail.org/post/20100106.0063
2009
----
Brown rot, potato - Australia: (QLD), new strain
http://promedmail.org/post/20090821.2958
and additional items on ralstonia diseases in the archives]
Topics
Species
