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: November 2016
Source: European Plant Protection Organisation (EPPO) Reporting Service 11/2016/217 [edited] <http://archives.eppo.int/EPPOReporting/2016/Rse-1611.pdf>
During studies conducted from 2007 to 2012 in Western Australia, _Potato spindle tuber viroid_ (PSTVd - EPPO A2 List) was detected in volunteer and wild plants in the Gascoyne Horticultural District. In this irrigated area, a wide range of temperate, tropical and subtropical crops are grown including solanaceous crops, and PSTVd was 1st detected [there] in field tomatoes (_Solanum lycopersicum_) in 2006. Since then, PSTVd has frequently been detected in field crops of tomato, pepper and chilli (_Capsicum_ spp.).
During these studies, PSTVd was detected in volunteer plants of tomato, pepper and chilli, as well as in the following wild and weed plants: _Atriplex semilunaris_, _Conyza bonariensis_, _Datura leichhardtii_, _Nicandra physalodes_, _Rhagodia eremaea_, _Solanum nigrum_ and _Streptoglossa_ sp. In addition, PSTVd was detected in another location in WA, in the Ord River irrigation area (Kimberley region) on _Physalis angulata_.
It is concluded that in these areas, volunteer and wild plants probably act as reservoirs for the viroid and that this may explain the occurrence of repeated PSTVd outbreaks in nearby solanaceous crops.
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Communicated by: ProMED-mail <promed@promedmail.org>
[_Potato spindle tuber viroid_ (PSTVd; genus _Pospiviroid_) is an important pathogen of solanaceous crops. Yield losses can be up to 65 per cent in potato and up to 50 per cent in tomato. Symptoms in potato may include spindly shoots, stunting of plants, severely distorted tubers (spindles) and delayed sprouting. In tomatoes, symptoms include leaf chlorosis and distortion, shortening of internodes, stunting of plants and absence of flowers. Capsicum plants often display only mild symptoms, and solanaceous ornamentals are often symptomless. All varieties of tomato and potato appear to be susceptible, but mild strains causing latent infections in some host cultivars exist.
PSTVd is seed transmitted in potato and tomato at a rate of up to 100 per cent, depending on the host cultivar. Tomato seed is considered an international quarantine risk (ProMED-mail post http://promedmail.org/post/20140122.2222560), and the viroid was shown to be present in the embryo and endosperm (see item 218 in the same source document above). Spread occurs also via infected plants or vegetative plant parts, pollen, mechanical means and plant-to-plant contact. PSTVd is exceptionally stable and can persist in dried sap or plant residue for considerable times. Only in the presence of _Potato leafroll virus_ can PSTVd also be transmitted by an aphid vector (_Myzus persicae_).
Due to the multiple potential transmission routes and the large number of host species, both epidemiology and control of PSTVd are complicated. Disease management relies mainly on removal of infected plants and other inoculum, phytosanitary procedures, as well as use of certified PSTVd-free seed and other planting material. Pospiviroids are considered an emerging phytosanitary threat worldwide because of their potential effects on a number of very important crops and the high risk of incursions via commercial imports.
The presence of PSTVd (and other pospiviroids) in symptomless weedy hosts has been reported from several countries. The report above adds additional potential reservoir species and confirms that the viroid can persist in a hot, arid environment.
In Australia, several previous outbreaks of PSTVd, including in the area where the survey above was conducted (ProMED-mail post http://promedmail.org/post/20101201.4322), were mostly attributed to imported infected seeds but considered to be successfully eradicated (for example, ProMED-mail post http://promedmail.org/post/20030804.1913). The report above provides an explanation why these eradication programmes failed to eliminate PSTVd from the crop growing areas.
Maps
Australia (with states):
<http://www.webookaustralia.com/images/australiamap.jpg>
Individual states via:
<http://www.mapsofworld.com/australia/states/>
Pictures
PSTVd symptoms on potato:
<http://vegetablemdonline.ppath.cornell.edu/Images/Potatoes/PotatoViruses/PotatoVirusfs7.jpg>,
<http://mcmanuslab.ucsf.edu/sites/mcmanuslab.ucsf.edu/files/put_your_BMS265_images_here/LM_potatoes.jpg>,
<https://www.agric.wa.gov.au/sites/gateway/files/PSTVd%20on%20Atlantic.JPG>,
<http://www.omafra.gov.on.ca/english/crops/facts/98-02514.jpg> (leaf) and <http://www.dpi.nsw.gov.au/__data/assets/image/0003/583842/above-ground-symptoms-of-infected-potato.jpg>
(whole plant, compared to healthy)
PSTVd affected tomato plants:
<http://www.forestryimages.org/images/768x512/0162082.jpg> and <https://www.agric.wa.gov.au/sites/gateway/files/PSTVd%20on%20Rutgers.JPG>
(compared to healthy)
Photo galleries of PSTVd symptoms on tomato and potato:
<http://www.forestryimages.org/browse/subimages.cfm?SUB=11936> and <https://gd.eppo.int/taxon/PSTVD0/photos>
Links
Information on PSTVd:
<http://www.apsnet.org/edcenter/intropp/lessons/viruses/Pages/PotatoSpindleTuber.aspx>,
<https://gd.eppo.int/taxon/PSTVD0>,
<http://www.cabi.org/isc/datasheet/43659>,
<http://www.dpvweb.net/dpv/showdpv.php?dpvno=66> and via <http://www.apsnet.org/publications/apsnetfeatures/Pages/Viroids.aspx>
Detection methods and quarantine risk analysis of pospiviroids:
<http://www.efsa.europa.eu/en/efsajournal/pub/2330.htm> and <https://gd.eppo.int/download/standard/258/pm9-013-1-en.pdf>
PSTVd taxonomy via:
<http://ictvonline.org/virusTaxonomy.asp?version=2015>
- Mod.DHA
A HealthMap/ProMED-mail map can be accessed at:
<http://healthmap.org/promed/p/289>.]
[See Also:
Potato spindle tuber viroid, seed & breeding lines - Poland, Netherlands ex UK http://promedmail.org/post/20161020.4574403
Potato spindle tuber viroid - Netherlands: (northeast)
http://promedmail.org/post/20160916.4491923
Potato spindle tuber viroid, capsicum - Switzerland: 1st rep (AG,ZH)
http://promedmail.org/post/20160509.4209713
Potato spindle tuber viroid, capsicum - Netherlands: (ZH,LI)
http://promedmail.org/post/20160422.4175522
2014
----
Potato spindle tuber viroid, tomato - Dominican Republic
http://promedmail.org/post/20140508.2460224
Potato spindle tuber viroid, tomato seed: international spread
http://promedmail.org/post/20140122.2222560
2013
----
Pospiviroids - France, Poland: 1st reps
http://promedmail.org/post/20131218.2122275
Pospiviroids, tomato seed - Australia: quarantine intercepts.
http://promedmail.org/post/20130321.1597703
2011
----
Potato spindle tuber viroid, tomato - UK: (England)
http://promedmail.org/post/20110808.2403
2010
----
Potato spindle tuber viroid, vegetable crops - Australia: (WA)
http://promedmail.org/post/20101201.4322
Potato spindle tuber viroid, tomato - USA: (CA)
http://promedmail.org/post/20101117.4174
Potato spindle tuber viroid - Russia: update
http://promedmail.org/post/20101020.3801
and older items in the archives]
Topics
Species
