Scientific opinion on the risk to plant health posed by Arabis mosaic virus, Raspberry ringspot virus, Strawberry latent ringspot virus and Tomato black ring virus to the EU territory with the identification and evaluation of risk reduction options

Abstract

The Panel on Plant Health assessed the risk to plant health of Arabis mosaic virus (ArMV), Strawberry latent ringspot virus (SLRSV), Raspberry ringspot virus (RpRSV) and Tomato black ring virus (TBRV) for the European Union (EU) territory, and evaluated the current EU legislation and possible risk reduction options. These viruses are largely restricted to Europe and their vector nematodes and at‐risk hosts occur widely in Europe. Plants for planting were identified as the most significant entry pathway and the probability of entry is rated as unlikely to moderately likely for ArMV and as very unlikely to unlikely for RpRSV, SLRSV and TBRV. These ratings have moderate uncertainty. The probability of establishment is rated very likely with low uncertainty. The probability of local spread by natural means is likely, with low to medium uncertainty, whereas that of human‐assisted long‐distance spread is unlikely to moderately likely, with high uncertainty. Potential impact is rated minimal to minor in all hosts, with the exception of ArMV in grapevine, for which it is minor to moderate. These ratings have medium or high uncertainty. The current legislation addresses only two of the many host species of these viruses, but other weaknesses were also identified. If the current legislation were removed, no major consequences would be expected unless the industry simultaneously ceased its voluntary certification activity. Prohibition and the use of phytosanitary certificates, if covering the complete host ranges of the viruses and relying on appropriate tests, are the options with highest effectiveness against the risk of introduction whereas certification schemes and pest‐free areas or production sites are those with the highest effectiveness against the spread and impact risks. All options have limitations in feasibility, with uncertainty ratings from moderate to high. The combination of partially effective options may be highly effective in some crops.

Scientific Opinion on the pest categorisation ofStrawberry vein banding virus

“…However, the existence of efficient and widely adopted voluntary certification systems for strawberry constitutes a very strong limitation to the spread of SVBV and of other strawberry viruses through the plants for planting pathway (EFSA PLH Panel, 2013, 2014a, limiting opportunities for virus spread in the field by vector aphids. In areas where Chaetosiphon spp.…”

Known and Potential Invertebrate Vectors of Raspberry Viruses

“…nematode, where both viruses are transmitted by L. elongatus , whereas L. attenuatus is only known to transmit TBRV and L. macrosoma only transmit RpRSV [ 44 , 45 , 120 ]. Since both TBRV and RpRSV are vectored by L. elongatus , a mixed infection of these viruses is often observed and usually results in raspberry leaf curl disease [ 127 ]. Despite the number of nematode vectors reported, their role is still understudied due to their cryptic habitat and small size posing a challenge in detecting and verifying transmission.…”

Scientific Opinion on the pest categorisation of Strawberry latent C virus

“…Besides the fact that it infects both strawberry and wild strawberry (F. vesca) (Frazier, 1974: Martin and Tzanetakis, 2006, 2013, there is no precise information on the host range of SLCV.…”

“…The existence of efficient and widely adopted voluntary certification systems for strawberry constitutes a very strong limitation to the spread of SLCV and of other strawberry viruses through the plants for planting pathway (EFSA PLH Panel, 2013, 2014a. In this respect, the very sharp reduction in SLCV prevalence in North America over the past 50 years (Martin and Tzanetakis, 2006) appears to validate the prediction of McGrew (1987) that 'The production of cultivar clones free of SLCV and moderate care in isolation of seedling, selection, and nursery blocks from known sources, followed by continued replacement of certified fruiting-field stocks, should result in the disappearance of this disease'.…”

“…This is most probably a consequence of modern strawberry cultural practices, including the systematic use of certified plants for planting and the use of short rotation cycles which limit the build-up of infected materials. Such strategies are also widely used in the EU and have widely contributed to the general reduction of the impact of strawberry-infecting viruses, as illustrated in a recent industry hearing and in EFSA opinions addressing such agents EFSA PLH Panel, 2013, 2014a.…”