Commodity risk assessment of oak logs with bark from the US for the oak wilt pathogen Bretziella fagacearum under an integrated systems approach

Abstract

The European Commission submitted to the EFSA Panel on Plant Health a Dossier by USDA proposing a systems approach to mitigate the risk of entry of Bretziella fagacearum to the EU when trading oak logs with bark from the USA . Due to the forthcoming ban of methyl bromide ( MB ), the Dossier indicates sulfuryl fluoride ( SF ) as the substitute fumigant for this commodity. After collecting additional evidence from USDA , EU NPPO s, external experts and the published literature, the Panel performed a quantitative assessment on the likelihood of pest freedom for B. fagacearum at the point of entry in the EU , comparing the proposed systems approach with those already implemented by Commission Decision 2005/359/ EC . The Panel provided also a non‐quantitative assessment for all risk reduction options ( RRO s) proposed to be undertaken in the EU , from the point of entry to processing at the sawmill. The quantitative assessment until the EU point of entry, based on experts’ judgement, indicated that: i) the most effective import option remains the current one with MB (95% certainty that between 9,573 and 10,000 containers per 10,000 would be free of B. fagacearum ), followed by that with SF (95% certainty that between 8,639 and 10,000 containers per 10,000 would be free of B. fagacearum ) and, last, by the other existing option based on delivering white oak logs in certain periods of the year to certain regions of the EU without fumigation (95% certainty, between 7,803 and 10,000 containers per 10,000). RRO s proposed to be undertaken in the EU are expected to further reduce the risk of establishment of B. fagacearum , should these RRO s be regulated, correctly implemented and checked by NPPO s. A wood pathway analysis is needed to quantitatively assess the importance of each measure and to optimise regulatory actions and risk management efforts.

Commodity risk assessment of ash logs from the US treated with sulfuryl fluoride to prevent the entry of the emerald ash borer Agrilus planipennis

“…Information on the efficacy of sulfuryl fluoride against pests in wood logs were also gathered from EFSA PLH Panel (2020).…”

“…The available scientific information, including previous EFSA opinions on the relevant pest and relevant fumigant (e.g. EFSA, 2020; EFSA PLH Panel, 2020), was considered.…”

“…They are considered strong fliers, capable of covering distances between 3 and 20 km per day in natural conditions, although most of the dispersal remains within 100 m from the emergency point where host plants are largely available (Mercader et al, 2009;Taylor et al, 2010); the effect of the wind on the flight distance is still unclear (Siegert et al, 2010). Annual spread rates of 2.5-80 and 13-41 km were reported in North America and European Russia, respectively (EFSA, 2020). A maximum flight distance of 1,600 m per year has been estimated and might occur for the EU regions where ash is present (EFSA, 2019).…”

International supply chain handling practices and the quality of heat-treated, white oak veneer logs

“…Other states in the US are increasingly restricting the use of this fumigant. As of December 31, 2020, the EU prohibited shipment of methyl bromide fumigated, oak logs, with bark, from the US to EU countries (Bragard et al 2020).…”

Benchmarking a fast and simple on-site detection assay for the oak wilt pathogen Bretziella fagacearum

“…Since it is not possible to cure infected trees, management of oak wilt is focused on preventing additional spread and involves the establishment of root graft barriers and trench inserts, removal of potential spore-producing trees, preventive fungicide injections, a ban on firewood transportation between different areas and restricted oak tree wounding activities to certain periods of the year (O'Brien et al, 2000;Wilson, 2001;Koch et al, 2010). The European Union is also tightening its restrictions when trading oak logs with bark from the USA (EFSA et al, 2020). For these efforts to be successful, rapid confirmation of infection is critical.…”