Potato spindle tuber viroid (PSTVd)
Significance: In recent years, Potato spindle tuber viroid (PSTVd) was identified in several hosts other than potato, including tomato, pepper, pepino and several ornamental plant species (e.g. Brugmansia sp., Solanum jasminoides, S. rantonnetii, Streptosolen jamesonii) (EPPO, 2008; Verhoeven et al., 2008). Infected plants may be asymptomatic. These finds in non-potato hosts have led to an increased PSTVd-awareness amongst growers and certifying agencies in many countries, prompting increased PSTVd surveillance and testing in some regions. Recently, through PCR and inoculation studies, PSTVd was identified in symptomless cuttings of Cape gooseberry (Physalis peruviana) in Turkey and on young seedlings of this host growing in Germany (Verhoeven et al., 2009).
Issues of Concern: PSTVd is a quarantine pest for all NAPPO countries (NAPPO, 2007). In recent years, other countries reported PSTVd in ornamental plants as well as greenhouse vegetable crops such as tomato and pepper. As pointed out by Verhoeven et al., (2009), this is believed to be the first report of PSTVd in Physalis peruviana. As PSTVd is easily mechanically transmitted between plants/crops, and P. peruviana can be symptomlessly infected, such plants could act as sources of inoculum for the viroid to move into crops like potato and tomato. Finding the viroid in Physalis seedlings also suggests that, like in the case of tomato, potato, and pepino, seeds of this host may also be a potential pathway for spreading the viroid.
EPPO, 2008. Potato spindle tuber viroid - Italy: 1st report, new host. January 2008. European Plant Protection Organisation (EPPO) Reporting Service 1/2008/008 [edited] http://archives.eppo.org/EPPOReporting/2008/Rse-0801.pdf. (Also reported by Pro-Med Plant (PRO/PL> Pospiviroids - Europe: 1st reps, new hosts).
NAPPO. 2007. RSPM No. 3. Requirements for Importation of Potatoes into a NAPPO Member Country. Originally drafted in 2003, reviewed in 2007. NAPPO Regional Standard for Phytosanitary Measures. North American Plant Protection Organization. Ottawa, Canada. Available online at: http://www.nappo.org/Standards/REVIEW/RSPM3-e.pdf or in Spanish at: http://nappo.org/Standards/REVIEW/RSPM3-s.pdf.
Verhoeven, J. Th. J., C. C. C. Jansen and J. W. Roenhorst. 2008. Streptosolen jamesonii 'Yellow', a new host plant of Potato spindle tuber viroid. Plant Pathology. Vol. 57:399.
Verhoeven, J. Th. J., M. Botermans, J. W. Roenhorst, J. Westerhof and E. T. M. Meekes. 2009. First Report of Potato spindle tuber viroid in Cape Gooseberry (Physalis peruviana) from Turkey and Germany. Plant Disease. Vol. 93 (3):316.