Quarantine viruses in strawberry

Raspberry ringspot virus (RpRSV), Strawberry crinkle virus (SCV), Strawberry latent ringspot virus (SLRSV) and Strawberry mild yellow edge virus (SMYEV) are quarantine viruses that should be avoided on strawberry (but also on Rubus and Prunus for RpRSV and SLRSV) propagation material in all strawberry growing regions. In order to assess the prevalence and status of these four regulated viruses in Belgium, an extensive survey was organized during the past two years.
Approx. 1000 samples were collected and tested taking into account a balanced geographical distribution based on production and historical/recent outbreak information.
Duplex PCR techniques were used to detect the viruses, grouping both aphid transmittable viruses, SCV & SMYEV, and both nematode transmittable viruses, RpRSV & SLRSV.
In both consecutive survey years outbreaks of SCV and SMYEV were observed in strawberry. In the 2011 and 2012 growing season SMYEV was detected at 5 and 3 locations, respectively. SCV was detected twice in 2011 and three outbreaks were pinpointed in 2012. Outbreak sites were dispersed over the whole of the Belgian strawberry growing area and on each site a monitoring strategy was set up, including sampling and testing of the aphid vectors. None of the nematode transmitted viruses was detected during the survey. Their status can therefore be considered as ‘absent’.
The obtained status information on the four viruses was put in a database following ISPM8 guidelines and transmitted to the federal authorities and will contribute to review the regulation status of these viral pathogens in Belgium.