Pest risk assessment of Diaporthe vaccinii for the EU territory

As requested by the European Commission, the EFSA Panel on Plant Health (PLH) Panel assessed therisk ofDiaporthe vacciniiin the EU, focusing on entry, establishment, spread and impacts on cultivatedand wildVacciniumspecies, the principal hosts being American and European cranberry and blueberry.Several outbreaks occurred in the EU since 1956, but most were eradicated except in Latvia. ThePanel considered entry via fruits and plants for planting. The risk of establishment from discardedinfected berries is much lower than from infected plants for planting, of which, potted plants andcuttings pose the greatest risk, while plug plants, derived from tissue culture and grown in pest freestructures, pose a low risk. Nine per cent of the EU is highly suitable for establishment of thepathogen, mostly in the SE and NE. Following establishment, the pathogen could spread naturally overshort range, and by human assistance over long range. Calculations with an integrated model forentry, establishment and spread, indicate that with current regulations, over a period of 5 years, a fewhundred cultivatedVacciniumplants and several thousandVacciniumplants in natural ecosystemswould contract the disease. The associated loss of commercial production is small, less than one tonneof berries per year. On natural vegetation, the median impact after 5 years was estimated to benegligible affecting a negligible proportion of the naturalVacciniumpopulation (29108). However,the uncertainty of this estimate was high, due to uncertainty about the rate of spread; in a worst-casescenario (99th percentile), almost 1% of plants in natural areas would become infected. Completederegulation (scenario A1) was predicted to increase the impact substantially, especially in naturalareas, while additional measures (scenario A2) would effectively eliminate the entry of infected plantsfor planting, further reducing the impacts below the current situation.