Update on the situation of Potato spindle tuber viroid in the Netherlands
The NPPO of the Netherlands recently provided updated information about the situation of Potato spindle tuber viroid (Pospiviroid, PSTVd – EPPO A2 List) on its territory.
Eradication of PSTVd from potato breeding material
In August 2016, PSTVd was detected in potato (Solanum tuberosum) breeding material (EPPO RS 2016/176). The viroid was detected in 4 potato plants belonging to the same genotype, and which were grown in 2 small fields owned by a breeding company located in the municipality of Noordoostpolder. All infected material was destroyed. As no further detections of PSTVd have been made, the Dutch NPPO officially declared the eradication of this outbreak in June 2017.
Eradication of PSTVd from Capsicum annuum plants for planting (seedless cultivars)
In March 2016, the presence of PSTVd was confirmed in 5 greenhouses producing plants for planting of Capsicum annuum (several seedless cultivars). One glasshouse was located in the municipality of ‘Peel en Maas’ and the others in the municipality of Westland (EPPO RS 2016/083). In November 2016, another greenhouse (approximately 3 ha) producing seedless C. annuum was also found to be infected. By the end of 2016, measures for eradication were completed at all 6 production sites. As no further detections of PSTVd have been made, the Dutch NPPO officially declared the eradication of this outbreak in June 2017.
Interception of PSTVd on Solanum sisymbriifolium seeds imported from Asia
In May 2017, a Dutch breeding company reported to the NPPO a suspicion of PSTVd infection in a seed lot of Solanum sisymbriifolium* originating from Asia. Due to a low viroid concentration in the tested sample, the results of the diagnosis indicated that the detected Pospiviroid was most probably PSTVd but a final confirmation is still needed. In fact, this suspicion had initially been raised by the consignee of a third country to which the seed lot had been exported by the Dutch breeding company. This seed lot of 1400 kg had been produced in 2012, 2014 and 2015 by 2 Asian countries by order of the breeding company. All seed lots of the breeding company are currently under investigation. Tracing-back and -forward studies are ongoing. In the Netherlands, one seed lot has been sown and the resulting crop will be destroyed. So far, S. sisymbriifolium has not been recorded as a host plant of PSTVd.
The pest status of Potato spindle tuber viroid in the Netherlands is officially declared as: Transient in ornamentals (S. jasminoides); Pest eradicated in Dahlia, Solanum lycopersicum fruit production, Capsicum annuum fruit production and Solanum tuberosum breeding material.
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* Solanum sisymbriifolium is a tropical plant which is occasionally used in the Netherlands as a trap crop in fields infested by potato cyst nematodes. Full development of the plant is difficult to obtain under temperate climates. The Dutch NPPO explained that the plant breeder has gradually developed and marketed this crop since 2002. In 2008 and 2009, 15 fields of S. sisymbriifolium were sampled and tested for PSTVd. All results were negative.
Sources
NPPO of the Netherlands (2017-06).