A ProMED-mail post <http://www.promedmail.org>
ProMED-mail is a program of the International Society for Infectious Diseases <http://www.isid.org>
Date: Tue 13 Mar 2018
Source: HortiDaily [edited]
<http://www.hortidaily.com/article/41790/Italy-TYLCV-variant-risks-damaging-entire-economy>
Sicily is strategic for the country's agriculture, but currently has to deal with at least 2 major problems.
Salvatore Davino, University of Palermo, says, "First the New Delhi virus [_Tomato leaf curl New Delhi virus_; ToLCNDV], which first appeared in Sicily in 2015 [ProMED-mail post http://promedmail.org/post/20160327.4121164]. It started with cucurbits, the virus then moved to tomatoes after around 4 years. We are currently monitoring tomato crops.
"Another great problem is the IL23 variant of TYLCV [_Tomato yellow leaf curl virus_]. It originated autonomously as a genetic recombination of TYLCV and TYLCSV [TYLC Sardinia virus]. So far, it would seem that this new strain has the capability of overcoming the tolerance of selected plants to the previous strain. It's an extremely serious problem, as there are currently no tomato varieties that can tolerate [it]. The new variant was first observed in Ragusa [province] and has since moved towards Caltanissetta [province]. Thanks to the mild winters, vector _Bemisia tabaci_ could proliferate and contaminate nearby areas."
The situation is alarming. "Over the next few months, we will be able to make a real assessment that will take into consideration not only the phytopathological aspects affecting the territory, but also the economic loss that would derive from a pandemic."
--
communicated by: ProMED-mail <promed@promedmail.org>
[The viruses mentioned above are all species of genus _Begomovirus_ and belong to the tomato leaf curl and yellow leaf curl clades of the genus. Known species in these clades cause similar diseases on solanaceous, cucurbit and other crops and can lead to considerable yield losses. Symptoms may include distortion and yellowing of leaves and stems, stunting of plants, reduced flowering and severe loss of plant vigour. A large number of geographical variants of the viruses are being identified and many of them have now been classified as separate species. Frequent recombination events are considered to be the basis for the diversity within the clades. Variations in host range and specificity exist both amongst viral species and between different strains within species.
Begomoviruses are transmitted by different whitefly vectors (such as _Bemisia tabaci_ biotypes). Many can also be transmitted by mechanical means and grafting, but they are not seed transmitted. Whiteflies in themselves are serious pests of many vegetable crops. If virus sources are available locally, high vector numbers are often reflected in high levels of the viral diseases they transmit. Begomovirus control is particularly difficult in open field crops due to the widespread presence and wide host range of whiteflies. Disease management may include pathogen exclusion, vector control and elimination of possible pathogen and/or vector reservoir plants. In some cases, crop cultivars with increased virus resistance are available.
In some areas, leaf curl viruses are considered to be the biggest constraint to solanaceous and cucurbit crops, both in terms of yield losses (up to 100 per cent in tomato) and loss of fruit quality. The Mediterranean region collectively accounts for ca. 30 per cent of global tomato production (FAO). It is of major concern that it also has been identified as a 'hot spot' for emergence of new strains and species within the leaf curl/yellow leaf curl clades. TYLCV and related species, as well as _Bemisia_ vectors, have been added to the
A2 quarantine list of the European Plant Protection Organisation (EPPO); ToLCNDV has been added to the EPPO alert list.
Maps
Italy:
<http://www.lonelyplanet.com/maps/europe/italy/map_of_italy.jpg>
Italy, provinces and regions:
<http://www.lib.utexas.edu/maps/europe/italy_div96.jpg>
Europe, overview:
<http://www.youreuropemap.com/europe_map_political.gif>
Pictures
Leaf curl disease on tomato:
<http://susveg-asia.nri.org/images/svcorkipmt2.JPG>,
<http://www.daff.qld.gov.au/__data/assets/image/0018/55530/Tomato-leaf-curl-virus-35-days-250.jpg>,
<http://www.daff.qld.gov.au/__data/assets/image/0003/65847/Tomato-leaf-curl-virus-56-days-250.jpg>
and
<http://2.bp.blogspot.com/_bMncWNHcSHM/S_TwfAoj_yI/AAAAAAAAAjE/dvx1eij0RNU/s1600/leaf+curl+contaminated.jpg>
ToLCNDV symptoms:
<http://cienciacebas.files.wordpress.com/2013/09/aranda-1.jpg>
(zucchini) and
<http://cienciacebas.files.wordpress.com/2013/09/aranda-2.jpg>
(cucumber and melon)
Photo gallery of symptoms of different begomoviruses:
<http://www.forestryimages.org/browse/TaxImages.cfm?fam=651&genus=Begomovirus>
Whiteflies:
<https://apps.rhs.org.uk/Advice/ACEImages//SW1244_790940.jpg>
Links
Information on tomato leaf curl viral diseases:
<http://www.oisat.org/pests/diseases/viral/leaf_curl__virus.html> and <http://www.daff.qld.gov.au/plants/health-pests-diseases/a-z-significant/tomato-leaf-curl-virus>
Information on individual leaf curl viruses:
<http://www.natureasia.com/en/nindia/article/10.1038/nindia.2010.171>
(ToLCV),
<https://www.eppo.int/QUARANTINE/Alert_List/viruses/ToLCNDV.htm>
(ToLCNDV),
<http://www.ipm.ucdavis.edu/PMG/r783103311.html> (TYLCV) and <http://www.dpvweb.net/dpv/showdpv.php?dpvno=368> (TYLCV) Characterisation of TYLCV variants in the Mediterranean:
<https://link.springer.com/article/10.1007%2Fs00705-017-3674-9> (IL23
Sicily) and
<http://jgv.microbiologyresearch.org/content/journal/jgv/10.1099/jgv.0.000633?crawler=true&mimetype=application/pdf>
(Morocco)
TYLCV review:
<https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2965765/>
Characterisation of recombinant ToLCNDV strain in the Mediterranean
region:
<https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5127021/>
Taxonomy & current species lists of the clades via:
<https://talk.ictvonline.org/taxonomy/>
Information on whiteflies:
<http://www.issg.org/database/species/ecology.asp?fr=1&si=106>
EPPO quarantine & A2 alert lists:
<https://www.eppo.int/QUARANTINE/Alert_List/alert_list.htm> and <https://www.eppo.int/QUARANTINE/listA2.htm>
- Mod.DHA]
[See Also:
2017
---
Tomato leaf curl New Delhi virus, zucchini - Morocco: 1st rep (SS)
http://promedmail.org/post/20171206.5487792
Tomato leaf curl New Delhi virus, zucchini - Spain: (AN)
http://promedmail.org/post/20171114.5442041
2016
---
Vegetable viruses - Jamaica
http://promedmail.org/post/20160421.4173419
Tomato leaf curl virus, eggplant - India: (TN)
http://promedmail.org/post/20160415.4160915
Tomato leaf curl New Delhi virus, cucurbits - Italy: 1st rep (SC)
http://promedmail.org/post/20160327.4121164
2015
---
Vegetable viruses - Spain: (AN) alert
http://promedmail.org/post/20151204.3839034
2014
---
Tomato yellow leaf curl virus - Ghana: (TV)
http://promedmail.org/post/20140717.2616753
Tomato leaf curl New Delhi virus - Spain: (AN) alert
http://promedmail.org/post/20140321.2345942
2013
---
Tomato leaf curl New Delhi virus, zucchini - Spain: (MU) 1st report
http://promedmail.org/post/20131223.2131729
Yellow leaf curl & blights, tomato - Pakistan: (SD)
http://promedmail.org/post/20130206.1531086
2011
---
Vegetable viruses - Australia: (WA, QL)
http://promedmail.org/post/20110314.0817
Tomato yellow leaf curl, cowpea - China: new host, (SH)
http://promedmail.org/post/20110121.0244
2010
---
Tomato yellow leaf curl virus - Spain: (AL)
http://promedmail.org/post/20100923.3444
and older items in the archives]
Topics
Species
