Risk assessment of Retithrips syriacus for the EU

Following a request from the European Commission, the EFSA Panel on Plant Health performed a quantitative risk assessment for the EU of Retithrips syriacus (Mayet) (Thysanoptera: Thripidae), a polyphagous thrips, regarded as a tropical/subtropical pest occurring in several countries of Africa, South America, Asia and in the EU in Cyprus. The current risk assessment focused on potential pathways for entry, the climatic conditions allowing establishment, the expected spread capacity and the impact considering a time horizon of 10 years (2023–2032). The Panel identified the import of cut roses, persimmons, table grapes, as well as plants for planting of the genera Acalypha and Terminalia from third countries and those of Persea americana (avocado) from Israel as the most relevant entry pathways to consider. Over the next 10 years, an annual median estimate of 95 (90% Certainty Range, CR, ranging from 13 to 1832) potential R. syriacus founder populations per year are expected to successfully transfer to a suitable host in the EU NUTS2 regions where the climatic conditions are predicted as suitable for establishment; this value drops to a median of 4.6 founder populations per year (90% CR: 1 every 1.9 years – 85.6 per year) after considering the actual probability of establishment of a potential founder population. The estimated number of founder population per year is mostly driven by the import of cut roses and plants for planting. If such founder populations were to establish, R. syriacus is estimated to spread at a median rate of 0.05 km/year (90% CR 0.02–2.30 km/year) after a median lag phase of 1.1 years (90% CR 0.3–3.3 years). The overall impact on yield (expressed as % of the total agricultural production) directly attributable to R. syriacus when considering: (i) the main R. syriacus hosts in the EU, (ii) the areas of the EU where establishment is possible, (iii) the current agricultural practices and (iv) the evidence of impact from the countries where the pest is established for a long time, was estimated at 0.065% as the median value of the uncertainty distribution (90% CR 0.001%–0.571%). Options for risk reduction are discussed, but the effectiveness was not quantified.