ProMED
http://www.promedmail.org

Source: Corriere dell'Economia [in Italian, machine trans., summ. Mod.DHA, edited]
https://www.corrieredelleconomia.it/2024/10/12/il-batterio-delle-patate-e-presente-in-sardegna/

The presence of _Ralstonia solanacearum_ was confirmed on potatoes in Sardinia. The region immediately issued requirements for owners of production sites where potatoes infected with _Ralstonia solanacearum_ are present. They are to adopt phytosanitary measures issued by the Regional Phytosanitary Service aimed at eradicating the harmful organism.

Following the first detected outbreak, the Regional Plant Health Service conducted further investigations by taking 3 samples of self-produced seed potatoes from 3 different lots. These were sown in 3 different fields, each of 4 hectares. The results of the analyses were positive for _Ralstonia solanacearum_ for all 3 samples.

[Byline: Marcello Guerrieri]

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Communicated by:
ProMED

[Brown rot (also called bacterial wilt, slime rot) 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, before or after harvest. 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 _Ralstonia solanacearum_ (previously _Pseudomonas solanacearum_) species complex (Rss) currently includes _R. solanacearum_ (sensu stricto), _R. pseudosolanacearum_ and _R. syzygii_. Members 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.

Pictures
Potato brown rot symptoms:
https://media.potatopro.com/symptomy-ralstonia-solanacearum-1200.jpg,
https://plantpath.ifas.ufl.edu/rsol/images/Modules/Sptme1_BR.gif,
http://ephytia.inra.fr/en/I/29682/Mildiou6,
https://www.shutterstock.com/image-photo/brown-rot-potato-disease-caused-260nw-1937650438.jpg,
https://agritech.tnau.ac.in/crop_protection/images/potato_ph_diseasess/3.brownrot_3 and
https://image.shutterstock.com/shutterstock/photos/1889304943/display_1500/stock-photo-brown-rot-of-potato-disease-caused-by-a-soil-borne-bacterium-named-ralstonia-solanacearum-1889304943.jpg
Bacterial wilt symptoms on tomato plants:
https://giantveggiegardener.files.wordpress.com/2011/03/bacterial-wilt-u-of-wisconsin.jpg and
https://www.tomatonews.com/maj/phototheque/photos/Images_TN/6213_00.jpg

Links
Brown rot of potato:
http://www.plantmanagementnetwork.org/pub/php/review/2009/ralstonia/,
https://doi.org/10.1079/cabicompendium.45009,
https://agritech.tnau.ac.in/crop_protection/potato_phdiseases_3.html and
https://plantpath.ifas.ufl.edu/rsol/Trainingmodules/BRPotato_Module.html
Bacterial wilt of tomato:
https://www.tomatodirt.com/bacterial-wilt.html and
https://plantpath.ifas.ufl.edu/rsol/Trainingmodules/BWTomato_Module.html
Rss pathogen and disease information:
https://gd.eppo.int/taxon/RALSSO (with pictures),
http://www.oisat.org/pests/diseases/bacterial/bacterial_wilt.html,
https://doi.org/10.1046/j.1364-3703.2002.00102.x,
https://iant.toulouse.inra.fr//bacteria/annotation/cgi/ralso.cgi and
https://doi.org/10.3389/fpls.2014.00715
Rss races and biovars:
https://doi.org/10.1146/annurev-phyto-081211-173000,
https://doi.org/10.1094/PHP-04-18-0015-DG and
https://tinyurl.com/64x9n2xn (tomato and other Solanaceae)
Taxonomy of members of Rss via:
https://www.uniprot.org/taxonomy
- Mod.DHA