First record of alien pest Ophiomyia kwansonis (Diptera: Agromyzidae) in Europe and its phytosanitary significance.
The daylily leafminer Ophiomyia kwansonis (Diptera: Agromyzidae) was found in autumn 2011 at 4 localities in Ljubljana (2 private gardens, public park Tivoli and Botanical garden of University of Ljubljana) (locations: X=101090, Y=459525; X=100891, Y=461620; X=101037, Y=461344; X=99737, Y=462774). In 2012 it was found in the next six new locations: two in Ljubljana (Rimska road and Koseze), in the village Veliko Trebeljevo approx. 25 km air distance from Ljubljana, near the village Šmihel by Pivka, approx. 50 km from Ljubljana, Podturn near Dolenjske Toplice approx. 54 km from Ljubljana and arboretum Volčji Potok near Radomlje approx. 20 km from Ljubljana (locations: X=100496, Y=461632; X=103238, Y=459190; X=96365, Y=480155; X=56886, Y=436145; X=117053, Y=469814; X=66391, Y=503581). The adults were found on the daylilly plants from the end of May till October, when our observation ceased. This is the first report of O. kwansonis in Slovenia and in Europe as a pest of Hemerocalis spp. Its larvae bore longitudinal, whitish, meandering tunnels in the leaves of Hemerocallis plants (ophionoms), weakening them and reducing their ornamental value. Natural distribution of the species is Japan and Taiwan and in 2006 it was noticed in the United States of America where it is still spreading. The fly was not identified until 2011 and thus no legislative measures to prevent its spread were put in place. According to the observations from the USA O. kwansonis is a pest that causes economic damage in different species and ornamental varieties of Hemerocallis. Our preliminary and unsystematic observations show, that in Slovenia, due to the air distance spread of more than 70 km, the suppression of O. kwansonis is not possible any more. The introduction and the spread of this new pest again confirms the inefficiency of the phytosanitary system of the USA and of the European Union. To the authors knowledge no official measures against the pest were put into force in the EPPO region nor in the European phytosanitary system by the middle of October 2012, although the EPPO and SCPH were informed about the confirmation of the determination by the dipterologist dr. Michael von Tschirnhaus on 6 th July 2012. Daylily trade is the probable pathway of the pest since hibernation occurs mostly underground in the lower parts of withered leaves, which are attached to dormant stolons in trade. Pest status of Ophiomyia kwansonis officially declared by the NPPO of Slovenia is: Transient: non-actionable.