ProMED
http://www.promedmail.org

Source: European Plant Protection Organisation (EPPO) Reporting Service [summ. Mod.DHA, edited]
https://gd.eppo.int/reporting/article-7923
According to a Rosselkhoznadzor [Federal Service for Veterinary and Phytosanitary Surveillance] press release, 2 outbreaks of _Acidovorax citrulli_ (EPPO A1 List), the causal agent of bacterial fruit blotch disease of cucurbits, have been recently reported in central and southern Russia. This is the 1st report of this bacterium in Russia. Quarantine zones have been defined and phytosanitary measures are being applied.
[Source press release, with pictures (in Russian):
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Communicated by:
ProMED
[Bacterial fruit blotch (BFB) caused by _Acidovorax citrulli_ (Ac) is an economically important disease of cucurbit crops (family Cucurbitaceae) worldwide. For example, yield losses of up to 90% have been reported in watermelon (genus _Citrullus_). Several genetic groups have been identified for isolated strains which vary in host preferences within the cucurbit family. Symptoms on fruit may include spots, lesions and cracks; white bacterial ooze from the lesions; general fruit decay; young fruit are most susceptible. Leaves may develop brown lesions and infected seedlings may collapse. Disease development is favoured by warm, humid conditions.

The bacteria can be spread with or on seed and this is considered the main mode of spread between areas. They can also be spread by water (including crop irrigation), mechanical means (including animal and human activities) and infected plant materials (including crop debris). Disease management may include crop rotation, cultural measures (removal of pathogen reservoirs) and phytosanitation (for example, disinfection of farming tools). Chemical control may be effective, especially in glasshouses. Use of certified clean seed or transplants is essential. Disease susceptibility of commercial cucurbit cultivars varies.

Ac reports in solanaceous hosts have been few (see ProMED post 20210204.8162828) and were mostly connected with infected or contaminated seeds. In host range studies, symptoms were produced on leaves of tomato, aubergine and capsicum, but not on their fruits.

The related _A. avenae_ can affect a number of mainly grassy hosts, including cereal crops such as maize, millets, sorghum, oats, sugarcane and rice.

Pictures
BFB on cucurbits:
https://bugwoodcloud.org/images/768x512/1576246.jpg,
https://bugwoodcloud.org/images/768x512/1577739.jpg,
https://gd.eppo.int/media/data/taxon/P/PSDMAC/pics/1024x0/3000.jpg,
https://www.plantdiseases.org/sites/default/files/plant_disease/images/0983.jpg (internal fruit fermentation),
https://aggie-horticulture.tamu.edu/vegetable/files/2012/01/WMD43_43_43.jpg and
https://bugwoodcloud.org/images/768x512/5076088.jpg (leaf symptoms)
Ac micrograph:
http://bacmap.wishartlab.com/system/images/439/medium/Acidovorax_citrulli.jpg?1319706326

Links
Information on Ac & cucurbit BFB:
https://gd.eppo.int/taxon/PSDMAC/datasheet,
https://doi.org/10.1079/cabicompendium.2676,
https://apps.lucidcentral.org/pppw_v10/text/web_full/entities/watermelon_fruit_blotch_196.htm,
https://www.apsnet.org/edcenter/disandpath/prokaryote/pdlessons/Pages/BacterialBlotch.aspx and
https://www.plantmanagementnetwork.org/pub/php/management/bacterialblotch/ (with pictures)
Ac taxonomy:
https://www.uniprot.org/taxonomy/80869
Cucurbit taxonomy and list of genera:
https://www.itis.gov/servlet/SingleRpt/SingleRpt?search_topic=TSN&search_value=22337#null
EPPO A1 quarantine list:
https://www.eppo.int/ACTIVITIES/plant_quarantine/A1_list
- Mod.DHA]