ProMED
http://www.promedmail.org

Source: Daily News [in Thai, machine trans., summ. Mod.DHA, edited]
https://www.dailynews.co.th/news/3465490/
A warning has been issued to banana growers for ralstonia wilts and rhizome rot. The weather in the lower south is currently rainy and humid.
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Communicated by:
ProMED
[Ralstonia
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Bacterial wilts of banana and plantain known as moko, blood disease, and bugtok are caused by members of the _Ralstonia solanacearum_ (Rs) species complex (see link below). Within the complex, strains causing moko and bugtok are closely related, causing similar symptoms (including wilting, fruit rot, blackening of suckers, bacterial ooze), while the blood disease bacterium is more distantly related with characteristic red internal discolouration ("blood") of fruits and pseudostems. Moko is one of the most serious banana diseases, with reported yield losses of over 70 percent, but all 3 diseases cause severe yield losses and eventually death of the plants. Blood disease is suspected to be spreading from Indonesia to other countries in the region (ProMED post 20090727.2643). For diagnosis, molecular or microbiological tests are needed.

The bacteria are spread by water, wind, infected plant material or soil, as well as mechanical means (including human and insect activities). Suckers for propagation pose a high risk of spreading the diseases. Ornamental and weed species may serve as pathogen reservoirs. Infection can occur via roots or flowers, depending on host cultivar and pathogen strain. The primary means of control is exclusion from areas that are disease-free and eradication of infected plants where the pathogens are present. Disease management may also include cultural, chemical (for example, soil treatments) and biocontrol (antagonistic microorganisms) measures, or combinations of these. Certified clean planting material is essential. No resistant banana or plantain cultivars are known.

Members of the _R. solanacearum_ complex affect more than 200 plant species including many important crops (for example, causing brown rot of potato). The various races and biovars are active under different climatic conditions and in different hosts.

Rhizome rot
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Rhizome (soft) rots of banana can be due to bacterial (_Erwinia_ species) and fungal (such as _Cylindrocarpon musae_) pathogens. They are serious diseases which may lead to total crop losses. Symptoms may include yellowing and wilting of leaves, rotting of leaf bases and rhizomes, and eventual death of plants. Symptoms are not sufficient to distinguish between pathogens; reliable molecular diagnosis is required.

The pathogens are mostly soil borne and also spread with infected plant material (including seed rhizomes) or water and by mechanical means. Rhizome rots are favoured by humid conditions and high soil moisture. Disease management may include the use of well-drained planting sites, crop rotation, preventative chemical treatments of rhizomes for propagation, and use of certified disease-free planting material. However, in affected areas, even plants derived from disease-free rhizomes have a very high risk of being infected from local pathogen reservoirs.

Pictures
Moko disease symptoms:
https://www.plantmanagementnetwork.org/pub/php/management/bananapanama/images/ploetz13lg.jpg and
https://www.plantmanagementnetwork.org/pub/php/management/bananapanama/images/ploetz12lg.jpg
Banana blood disease symptoms:
http://4.bp.blogspot.com/_jsDi86zSP9Q/RzKdtPXvVCI/AAAAAAAAAK0/1JFTrInQG24/s320/Blood+disease+banana+cut+open+poss.jpg (pseudostem)

Links
Information on moko disease:
https://doi.org/10.1079/cabicompendium.44999,
https://plantix.net/en/library/plant-diseases/300016/moko-disease and
https://doi.org/10.1079/pwkb.20137804483
Information on _R. solanacearum_:
https://doi.org/10.1046/j.1364-3703.2002.00102.x,
https://iant.toulouse.inra.fr//bacteria/annotation/cgi/ralso.cgi and
_R. solanacearum_ taxonomy and description:
https://www.uniprot.org/taxonomy/305
Taxonomy of _Erwinia_ species via:
https://www.uniprot.org/taxonomy?query=erwinia
Fungal taxonomy via:
https://www.indexfungorum.org/Names/Names.asp
List of major diseases and pathogens of banana:
https://www.apsnet.org/edcenter/resources/commonnames/Pages/BananaandPlantain.aspx
- Mod.DHA]