First report of Phytophthora pluvialis in Belgium
Phytophthora pluvialis (EPPO Alert List) was first detected in the EPPO region in 2021 in the United Kingdom affecting western hemlock (Tsuga heterophylla) and Douglas-fir (Pseudotsuga menziesii) (EPPO RS 2021/227, RS 2022/060). Surveillance was conducted in Southern Belgium in 2023 in 15 Douglas-fir plantations. No symptoms on trees in plantations were observed. P. pluvialis was first detected in June and September 2023 in two water streams by baiting. In October 2023, needles from 38 Douglas firs plantation nearby one of the streams were collected and needles from two trees tested positive by real-time PCR. It was not possible to collect and test needles in the forest stand located near the other contaminated stream as the trees were mature and the branches inaccessible. The authors considered that its presence in the natural environment in two watercourses suggests that P. pluvialis may be established in Southern Belgium.
In order to determine the status of P. pluvialis, and if necessary to take appropriate measures, the NPPO of Belgium will conduct additional sampling of P. menziesii and T. heterophylla in nurseries as well as in (semi-)natural environments in forests throughout Belgium. The forest and plantation near the 2 contaminated streams will continue to be monitored in 2024.
The pest status of Phytophthora pluvialis in Belgium is officially declared as: Present, only in some parts of Wallonia, under surveillance.
Sources
Pirronitto S, Paquet F, Gaucet V, Chandelier A (2024) First report of Phytophthora pluvialis in Douglas fir plantations in Belgium. New Disease Reports 49(1), e12244. https://doi.org/10.1002/ndr2.12244
NPPO of Belgium (2024-02).