First Report of the Dagger Nematode Xiphinema rivesi, a Member of the X. americanum Group, from Slovenia.

Abstract

The dagger nematode, Xiphinema rivesi Dalmasso, is a virus-transmitting plant-parasitic nematode described from France (2) and also reported from Germany, Portugal, and Spain. While this species is only known from a few local sites within Europe, it is widespread in North America and also present in Peru and Pakistan (3). X. rivesi is able to transmit at least four North American nepoviruses, including Cherry rasp leaf virus, Tobacco ringspot virus, Tomato ringspot virus, and Peach rosette mosaic virus (1,4). In early spring 2002, nematodes of the X. americanum group were detected in soil samples taken near the roots of peach plants from an orchard in Bilje near Nova Gorica, Slovenia. Resampling in June and September at the same site and at an adjacent, approximately 30-year-old peach orchard confirmed the presence of the nematode in relatively high numbers (5 per 100 ml of soil). Adult females were isolated and sent for further identification to the Plant Protection Service in Wageningen, the Netherlands. The nematode was morphologically identified as X. rivesi and confirmed at the rDNA-level with internal transcribed spacer restriction fragment length polymorphism analysis. Because both sampling sites where the nematode was found are close to the Vipava River in an area of extensive stone and pome fruit production, it is likely that the nematode is also present in other orchards in this region. The origin of this quarantine nematode is unknown as there is no direct link with Slovenian orchards and import of plant material from abroad in the last decades. To our knowledge, this is the first report of X. rivesi in Slovenia and the fourth report of this species in Europe.