Commodity risk assessment of Ligustrum delavayanum topiary plants grafted on Ligustrum japonicum from the UK

Abstract

The European Commission requested the EFSA Panel on Plant Health to prepare and deliver risk assessments for commodities listed in Commission Implementing Regulation (EU) 2018/2019 as 'High risk plants, plant products and other objects'. This Scientific Opinion covers plant health risks posed by evergreen 3-to 20-year-old topiary plants of Ligustrum delavayanum grafted on L. japonicum in pots imported from the UK, taking into account the available scientific information, including the technical information provided by the UK. All pests associated with the commodity were evaluated against specific criteria for their relevance for this Scientific Opinion. One EU quarantine pest (Scirtothrips dorsalis), one EU protected zone quarantine pest [(Bemisia tabaci (European populations)] and two EU non-regulated pests (Diaprepes abbreviatus and Epiphyas postvittana) fulfilled all relevant criteria and were selected for further evaluation. For the selected pests, the risk mitigation measures described in the technical dossier from the UK were evaluated taking into account the possible limiting factors. For these pests, an expert judgement is given on the likelihood of pest freedom taking into consideration the risk mitigation measures acting on the pest, including uncertainties associated with the assessment. While the estimated degree of pest freedom varied among pests, E. postvittana was the pest most frequently expected on the commodity. The Expert Knowledge Elicitation indicated, with 95% certainty, that 9,724 or more living sculptures per 10,000 would be free from E. postvittana.

Pest categorisation of Diaprepes abbreviatus

“…Natural enemies targeting the eggs (Jacas et al, 2010;Diaz Montilla et al, 2013) and the larvae/pupae in the soil (McCoy et al, 2000) have been described and used in the field in the USA.…”

“…Action (non‐statutory) was taken to manage the population and by 2014, it was rarely found, and since then, there have been no further reports (DEFRA, unpublished data). The commodity risk assessment of Ligustrum delavayanum topiary grafted on L. japonicum plants from the UK performed by EFSA (EFSA PLH Panel, 2022) reports that D. abbreviatus was last found there in 2014, and the pest may no longer be present. Although the status in the UK was ‘present: transient’ by the UK NPPO (EFSA PLH Panel, 2022), there has not been any finding since 2014.…”

“…Indeed, D. abbreviatus is frequently intercepted in the USA on both live plants and nursery containers, where adults may be also found as hitchhikers (Grafton‐Cardwell et al., 2004; Jetter and Godfrey, 2009). Although cut branches and flowers could carry both eggs and adults of D. abbreviatus (EFSA PLH Panel, 2022), adults usually drop from the feeding substrate when disturbed. Therefore, these entry pathways are considered as highly unlikely for adults (hitchhikers) and only considered for eggs in this categorisation.…”

“…According to EFSA PLH Panel (2022), ‘live plants with soil are pathways for all life stages of D. abbreviatus ’. Indeed, D. abbreviatus is frequently intercepted in the USA on both live plants and nursery containers, where adults may be also found as hitchhikers (Grafton‐Cardwell et al., 2004; Jetter and Godfrey, 2009).…”

“…(2006)St Kitts‐NevisPresent, no detailsEPPO (online); CABI (1980)St Vincent and the GrenadinesPresent, no detailsEPPO (online); Blackwelder (1947)Trinidad and TobagoPresent, no detailsEPPO (online); Sirjusingh et al. (1992)EU (27)PortugalPresent, no detailsPortuguese NPPO (Appendix E)Other EuropeCanary Islands (Spain)Present, restricted distributionSpanish NPPO (Appendix C)UKPresent, transientUK NPPO in EFSA PLH Panel (2022)…”