A ProMED-mail post <http://www.promedmail.org>
ProMED-mail is a program of the International Society for Infectious Diseases <http://www.isid.org>
In this posting:
[1] Egypt: 1st report, new hosts
[2] Kenya, Pakistan, Brazil: 1st reports and new host
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[1] Egypt: 1st report, new hosts
Date: May 2020
Source: European Plant Protection Organisation (EPPO) Reporting Service 05/2020/103 [edited] <https://gd.eppo.int/reporting/article-6781>
In autumn 2013, tomato plants (_Solanum lycopersicum_) presenting symptoms of leaf yellowing were observed both in the greenhouses and fields of the experimental station of the Faculty of Agriculture at Giza governorate.
The presence of _Tomato chlorosis virus_ (_Crinivirus_, ToCV - EPPO A2 List) in tomato plants was confirmed by RT-PCR. Plants in the vicinity of the infected sites were tested for the presence of ToCV. Out of 52 different plant species tested within 22 families, 44 tested positive for ToCV. 37 out of these 44 plant species were considered as new hosts for ToCV.
In another survey in 2017-2018, symptomatic and asymptomatic tomato samples were collected from open fields from Fayoum, Giza, and Nobaria regions in northern Egypt and tested for a number of viruses. ToCV was detected in 5 out of 36 samples.
[Source publications:
<http://www.fspublishers.org/published_papers/26413_doi%2015.1375%20IJAB-19-1446%20(7)%2029-01-2020%20F.pdf>
and <https://scialert.net/abstract/?doi=pjbs.2019.83.94>
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Communicated by: ProMED-mail <promed@promedmail.org>
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[2] Kenya, Pakistan, Brazil: 1st reports and new host
Date: May 2020
Source: European Plant Protection Organisation (EPPO) Reporting Service 05/2020/091 [edited] <https://gd.eppo.int/reporting/article-6769>
_Tomato chlorosis virus_ is first reported from Kenya. Symptomatic tomato leaves were collected in September 2017 from 4 regions and ToCV was detected by RT-PCR in samples from 2 counties (Kiambu and Kirinyaga).
_Tomato chlorosis virus_ is first reported from Pakistan. In March 2019, a survey of tomato was conducted in the Multan district (Punjab province). ToCV was detected in 27 out of the 30 samples taken from symptomatic plants. _Tomato infectious chlorosis virus_ (TICV) was not detected. The authors note that ToCV and its vector _Bemisia tabaci_ are widespread in tomato crops in this region.
_Tomato chlorosis virus_ was first detected on cucumber (_Cucumis sativus_). Plants exhibiting chlorosis and mottling symptoms on young leaves were found in a commercial greenhouse, in State of São Paulo, Brazil, in February 2019.
[Source publications:
Kenya: <https://doi.org/10.1016/j.sciaf.2020.e00286>,
Pakistan: <https://doi.org/10.1094/PDIS-12-19-2732-PDN> and
Brazil: <https://doi.org/10.1094/PDIS-07-19-1490-PDN>]
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Communicated by: ProMED-mail <promed@promedmail.org>
[_Tomato chlorosis virus_ (ToCV; genus _Crinivirus_) infects crops in the family Solanaceae, as well as weeds which may serve as pathogen reservoirs. It can also affect a number of crop and ornamental species in other families such as Cucurbitaceae (which include cucumber mentioned above). Symptoms on tomato leaves may include irregular chlorotic mottle, interveinal yellowing, necrotic flecks, and possible distortions. No obvious symptoms develop on fruit and flowers, but fruit size and numbers are reduced due to a loss of photosynthetic area. Significant yield losses occur as a result, but symptom severity varies with host cultivars. Symptoms may be confused with nutritional problems and are also similar to those of the related _Tomato infectious chlorosis virus_ (TICV; mentioned in item 2 above) of the same genus.
ToCV is transmitted by a number of whitefly vectors, including _Bemisia tabaci_ mentioned above, and outbreaks are usually associated with high vector populations. Whiteflies are a serious pest in themselves and have also been reported to transmit over 100 virus species. Multiple infections with viruses sharing these vectors (for example, coinfection of ToCV and TICV, see ProMED-mail post
http://promedmail.org/post/20140808.2671012) are not unusual and may result in symbiotic enhancement of symptoms (synergism) of the co-infecting viruses.
Control of whitefly transmitted viruses is particularly difficult in open field crops due to the widespread presence and wide host range of whiteflies. Disease management of these viruses is difficult and includes vector control, removal of reservoirs of both virus and vectors, use of crop varieties with increased pathogen tolerance and clean planting material.
Elsewhere in item 2, the related _Lettuce chlorosis virus_ (also genus _Crinivirus_) is reported for the first time from Brazil on ornamental species.
Maps
Egypt:
<http://healthmap.org/promed/p/8480> and <http://mapsof.net/egypt/egypt-map1> (governorates)
Kenya:
<http://healthmap.org/promed/p/174> and
<https://i.pinimg.com/originals/e5/5b/d7/e55bd7154cc09d4606fc8b3f9e01c057.jpg>
(counties)
Pakistan:
<http://healthmap.org/promed/p/1243> and <https://geology.com/world/pakistan-province-map.gif> (provinces)
Brazil:
<http://healthmap.org/promed/p/45784> and <https://overland.org.au/wp-content/1-Brazil-Regions.jpg> (states)
Pictures
ToCV symptoms on tomato:
<http://www.scielo.br/img/revistas/tpp/v36n4/a07fig01.jpg>,
<http://3.bp.blogspot.com/-V7pjNeP6jMk/TyspbW49OJI/AAAAAAAAA9Q/fhSoxY-LYWI/s1600/ToCV+en+tomate.jpg>,
<https://gd.eppo.int/media/data/taxon/T/TOCV00/pics/1024x0/3511.jpg>
and
<http://www.growgardentomatoes.com/image-files/tomato-chlorosis-virus-2.jpg>
Whiteflies:
<https://www.planetnatural.com/wp-content/uploads/2012/12/whitefly.jpg>
and
<https://www.pinpointpestcontrol.com/images/whitefly-on-plant.jpg>
Links
ToCV information:
<https://gd.eppo.int/taxon/TOCV00> (with pictures), <https://www.plantwise.org/KnowledgeBank/Datasheet.aspx?dsid=54069>,
<http://www.growingproduce.com/article/14078/pest-of-the-month-tomato-chlorosis-virus>,
<https://apsjournals.apsnet.org/doi/10.1094/PDIS-01-16-0054-RE>,
<https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5985646/>, and via <https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/tomato-chlorosis-virus>
Virus taxonomy via:
<https://talk.ictvonline.org/taxonomy/>
Information on whitefly vectors:
<http://www.ipm.ucdavis.edu/PMG/r783301211.html> and <http://www.issg.org/database/species/ecology.asp?fr=1&si=106>
EPPO A2 quarantine list:
<https://www.eppo.int/QUARANTINE/listA2.htm>
- Mod.DHA]
[See Also:
Undiagnosed disease, tomato - India (02): (MH) multiple viruses
http://promedmail.org/post/20200528.7388319
2018
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Tomato chlorosis virus - Netherlands
http://promedmail.org/post/20180719.5914214
2015
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Vegetable viruses - Spain: (AN) alert
http://promedmail.org/post/20151204.3839034
2014
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Tomato chlorosis virus - Tunisia: 1st rep (KR)
http://promedmail.org/post/20140808.2671012
2013
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Tomato chlorosis virus - China: 1st rep (BJ)
http://promedmail.org/post/20130916.1946775
2008
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Tomato chlorosis virus - Cuba: 1st report
http://promedmail.org/post/20080530.1741
2007
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Tomato chlorosis virus - Turkey, Mayotte: 1st reports
http://promedmail.org/post/20071215.4030
and older items in the archives]