Grapevine roditis leaf Discoloration-associated virus: express pest risk analysis for Ukraine

Abstract

Aim. To conduct an express pest risk analysis of Grapevine Roditis leaf discoloration-associated virus (GRLDaV) for Ukraine, a virus that has been related to a grapevine disease and was included in the EPPO Alert List in 2018. Methods. The phytosanitary risk analysis was carried out on the basis of an analytical review of expert literature and in accordance with the EPPO Decision-support scheme for an Express Pest Risk Analysis (EPPO, 2012) and with methodological recommendations for Ukraine (Pylypenko et al, 2012). The possibility of further spread and the potential range of the virus were determined using modern software packages AgroAtlas (Afonin and Li, 2011; Shumilin and Li, 2009), MapInfo Pro15.0 (ESTIMap®) and IDRISI SELVA (Clarklabs®). Results. An express pest risk analysis of GRLDaV for Ukraine was carried out for the first time. Outbreaks of the virus were first detected in the 1980ies in Greece (Rumbos, Avgelis, 1989) and from 2014–2018 in: Italy (Chiumenti et al, 2015, 2016; Maliogka et al, 2015), Turkey (Adan, 2016; Serçe et al, 2018) and Croatia (Vončina et al, 2018). Climatic predictors were analyzed in the outbreaks of the countries where the causal agent of the disease was identified. The potential range of GRLDaV in Ukraine has been established in case of importing infected planting material with further spreading of the virus. Risk management measures are proposed, which envisage including GRLDaV in the list of the Regulated Non-Quarantine Harmful Organisms of Ukraine. Conclusions. There is a possibility of introduction, further spread, and harmfulness of Grapevine Roditis leaf discoloration-associated virus in Ukraine, which is due to the presence of the host plant (grapevine, Vitis vinifera ssp. vinifera L.) and the corresponding climatic conditions of the southern and (part of) western Ukraine, where grapevine is cultivated on an industrial scale. The introduction of GRLDaV into Ukraine is possible as a result of the import of GRLDaV-infected grapevine planting material from the countries where the virus has been reported and presumably is still present. The current Ukrainian phytosanitary measures cannot reliably prevent the risk of intoduction of GRLDaV into Ukraine. The inclusion of GRLDaV in the List of the Regulated Non-Quarantine Harmful Organisms of Ukraine with the recommendation of permission to import grapevine planting material certified for the absence of GRLDaV (from the countries where the virus is reported) or mandatory testing of imported grapevine planting material for the presence of GRLDaV (from areas where such certification is absent), can be an effective risk management measure. It requires the producers and importers of grapevine planting material to include GRLDaV virus in their certification schemes to prevent eventual further spreading of the virus. It is recommended to do a nation-wide survey to determine the likelihood of the presence of GRLDaV in the region. Further research to identify possible natural virus vectors and to develop methods of (latent) GRLDaV diagnostics are needed. Finally additional studies on prevention and control of the virus (including breeding for resistance) are also required.