Following a request from the European Commission, the Panel on Plant Health was requested to provide a scientific opinion on a technical file submitted by the US Authorities to support a request to list a new option among the EU import requirements for wood (except in the form of dunnage, spacers, pallets or packing material) of Agrilus planipennis host plants. The request was supported by a scientific publication:
Myers SW, Fraser I and Mastro VC, 2009. Evaluation of heat treatment schedules for emerald ash borer (Coleoptera: Buprestidae). Journal of Economic Entomology, 102, 2048-2055.
The Panel analysed the relevant literature pertaining to the biology, host-plants and geographic distribution of A. planipennis, common name Emerald Ash Borer (EAB) and gave particular attention to the published articles describing control measures, with a special focus on that of Myers et al. (2009).
During the critical review of the different datasets provided by the US Authorities, the Panel found important inconsistencies. Therefore, in order to reduce uncertainties on the results of the analyses, four datasets were considered to explore the dependence of the model outcome on the possible input datasets.
The analysis of the aggregated data used by Myers et al. (2009) based on a Probit regression model showed that the proposed heat treatment of 60 °C/60 min cannot guarantee a control level of 99 % or higher. The analysis of the individual data using a Probit regression model showed that it is likely to observe one surviving emerald ash borer out of an infestation of 100 after the proposed heat treatment of 60 °C/60 min. To ensure a control level of 99 % the temperature of the heat treatment of 60 min should be higher than 70 °C. Results obtained with the Poisson log linear model showed that the estimated probability that one insect or more per m2 survive the proposed heat treatment was higher than 0.6 and that there is a 0.1 probability that three insects or more per m2 survive the proposed heat treatment.
The rate of survival of EAB prepupae after heat treatment documented in the additional published studies that were examined, suggests that individuals may survive after exposure to 55 ºC for 120 min, to 56 ºC for 60 min and to 60 ºC for 30 min. Therefore none of these treatments are effective in eliminating the EAB from infested wood. These results do not allow any conclusion regarding the effectiveness of the heat treatment under scrutiny (60 °C/60 min).
Based on the results of the analyses it performed, the Panel concludes with a low uncertainty that A. planipennis is likely to survive the proposed heat treatment of 60 °C/60 min, and that the alternative option proposed in the technical file submitted by the US Authorities does not guarantee the wood to be free of A. planipennis.