Presence of Contarinia pseudotsugae suspected in the Netherlands
The NPPO of the Netherlands recently informed the EPPO Secretariat of the finding of an insect species, tentatively identified as Contarinia pseudotsugae (Diptera: Cecidomyiidae – Douglas fir needle midge) on numerous forest trees of Pseudotsuga menziesii (Douglas fir) at 4 locations in the provinces of Gelderland, Limburg and Noord-Brabant. These findings were made in November 2015 in the framework of the yearly Dutch survey of forest stands targeting fungal pathogens (Mycosphaerella spp.). Interestingly, a Douglas fir needle midge, also tentatively identified as C. pseudotsugae has been reported in Belgium (see EPPO RS 2016/007). The fact that C. pseudotsugae has been found at four widely dispersed locations in the Netherlands in natural stands planted with thousands of Douglas fir trees indicates that the pest is now established and has probably been present for several years. The current impact appears to be limited and corresponds to minor wilting symptoms of the needles on lower branches. However, it is noted that C. pseudotsugae might pose a risk to young trees in nurseries. The origin of this finding is unknown but so far, C. pseudotsugae and related species causing similar types of damage (e.g. C. cuniculator and C. constricta) were only known to occur in North America. No official phytosanitary measures were taken due to the wide distribution of the pest and that fact that it has probably been present for a long period. A quick scan is being carried out by the Dutch NPPO to evaluate the potential risks presented by C. pseudotsugae.
Pictures of C. pseudotsugae in the Netherlands were kindly provided by the Dutch NPPO and can be viewed at: https://gd.eppo.int/taxon/CONTPS/photos
The pest status of C. pseudotsugae in the Netherlands is officially declared as: Present, in specific parts of the areas where host plants are grown.
Sources
NPPO of the Netherlands (2015-12).