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Date: April 2024
Source: European and Mediterranean Plant Protection Organisation (EPPO) Reporting Service 04/2024/075 [summ. Mod.DHA, edited]
https://gd.eppo.int/reporting/article-7825


_Beet necrotic yellow vein virus_ (_Benyvirus_, EPPO A2 List - rhizomania) is reported for the first time from Tunisia. The virus was detected in a commercial beet (_Beta vulgaris_) field.

[Ref: S. Nahdi et al (2022). First survey of beet viruses and their relative vectors on beet (_Beta vulgaris_) species in Tunisia. Abstract of a paper presented at the 13th Arab Congress of Plant Protection, Hammamet 2022.]

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Communicated by:
ProMED

[Rhizomania is one of the most serious diseases of sugarbeet worldwide. It is caused by _Beet necrotic yellow vein virus_ (BNYVV; genus _Benyvirus_), which is spread by the fungus-like root parasite _Polymyxa betae_. Symptoms include excessive production of roots, distortion and discolouration of roots, as well as chlorosis and distortion of leaves. Root size and sugar yield is severely reduced. The vector, and with it the virus, is easily spread with contaminated soil to new fields. It survives for decades in the soil as cysts, which can release zoospores carrying infectious virus when water becomes available. Disease management includes cultural practices and genetic resistance.

_Polymyxa_ is a group of poorly studied fungus-like organisms informally called 'plasmodiophorids'. Members can transmit a range of viruses in several genera (including _Furovirus_, _Benyvirus_, _Bymovirus_) that cause serious diseases in a range of crops. The related _P. graminis_ transmits viruses of cereals (e.g., _Barley yellow mosaic virus_, ProMED post 20230602.8710365). The viruses are protected from the environment within the resting spores (cysts), which can remain viable for decades in soil or dry plant matter. Disease management of the associated soil-borne viruses is difficult and mainly relies on virus-resistant crop cultivars.

Pictures
Rhizomania, root symptoms:
https://www.apsnet.org/edcenter/disandpath/viral/pdlessons/PublishingImages/rhizomaniasugarbeet_fig10.jpg and
https://c8.alamy.com/comp/2DRXGRK/rhizomania-symptom-of-hairy-secondary-root-development-and-distortion-caused-by-beet-necrotic-yellow-vein-virus-bnyvv-to-sugar-beet-greece-2DRXGRK.jpg
Rhizomania, leaf symptoms:
https://www.apsnet.org/edcenter/disandpath/viral/pdlessons/PublishingImages/rhizomaniasugarbeet_fig8.jpg
Beet plants with rhizomania:
https://www.apsnet.org/edcenter/disandpath/viral/pdlessons/PublishingImages/rhizomaniasugarbeet_fig6.jpg
_P. graminis_ in barley root cells, microscopy:
https://www.dpvweb.net/dpvfigs/d374f05.png and
https://media.springernature.com/original/springer-static/image/art%3A10.1007%2Fs13313-010-0015-9/MediaObjects/13313_2010_15_Fig2_HTML.gif

Links
Information on rhizomania:
https://doi.org/10.1094/PDIS-92-4-0581 and
https://gd.eppo.int/taxon/BNYVV0 (with distribution map and pictures)
Description and history of BNYVV:
https://www.dpvweb.net/dpv/showdpv/?dpvno=391 and
https://doi.org/10.1094/MPMI-10-10-0241
Virus taxonomy via:
https://ictv.global/taxonomy
_P. betae_ taxonomy:
http://www.indexfungorum.org/Names/NamesRecord.asp?RecordID=337464
EPPO A2 quarantine list:
https://www.eppo.int/ACTIVITIES/plant_quarantine/A2_list
- Mod.DHA]

See Also

2016
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Rhizomania, sugar beet - South Africa: 1st rep (WC) 20160602.4260593
2010
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Rhizomania, virus yellows, sugarbeet - UK: new strain 20100220.0582
2005
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Beet yellow vein virus, sugarbeet - Morocco: 1st report 20051112.3310
2003
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Rhizomania, sugar beet - USA (Great Lakes region) 20030210.0356
Rhizomania, sugar beet - Egypt 20030719.1769
2002
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Rhizomania, sugar beet - USA (Oregon, Washington) 20020124.3369
Beet necrotic yellow vein, sugar beet - UK (England) 20020827.5164
Beet viruses, sugar beet - Syria 20021218.6089
2001
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Beet necrotic yellow vein benyvirus - Denmark 20010509.0893
Rhizomania, benyvirus, sugar beet - UK 20011121.2851
2000
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Beet necrotic yellow vein benyvirus - Syria 20000124.0123
Beet necrotic yellow vein benyvirus - Sweden 20000525.0824
Beet necrotic yellow vein benyvirus - Sweden (02) 20001128.2076

Website: http://www.isid.org

Published: May 14, 2024