Quickscan Contarinia cf. pseudotsugae
The present Quickscan was conducted after the finding of a for Europe new gall midge species, Contarinia cf. pseudotsugae on Douglas fir (Pseudotsuga sp.). As far as known, it is the first finding of the species outside North America. The identification of the species is tentative because three different gall midge species are known to occur on Douglas fir in Canada and the USA and adults need to be reared to identify the species (it might even be that more than one species has been introduced). Among the three species, C. pseudotsugae is the economically most important one in North America. It can cause severe defoliation, twig die-back and stunted growth of especially younger trees. Findings at four locations in the Netherlands in natural stands indicate that the pest is established and has been present for several years already. Its impact in these natural stands is unknown. The species may affect spontaneous regrowth in natural stands and may especially pose a risk for young tree nurseries. It is unknown how the pest was introduced. Import of plants of Pseudotsuga from non-European countries has been prohibited in the EU for more than 20 years already.
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