Quarantine nematodes in Swiss vegetable growing

Root-knot nematodes (Meloidogyne spp.) are the most important group of plant-parasitic nematodes in Switzerland causing significant problems in vegetable production areas. The most common root-knot nematode species is Meloidogyne hapla, followed by the tropical and subtropical species M. incognita, M. arenaria and M. javanica, which are found in greenhouses only. In surveys conducted in the years 2002 to 2006, the quarantine nematodes M. chitwoodi and M. fallax were found in greenhouses in Switzerland. However, these quarantine nematodes were confined to a few greenhouses only and have not yet spread further confirming that the phytosanitary measures were successfully implemented. From 2006 to 2008, only M. fallax could be identified in samples from infested greenhouses and heated plastic tunnels. An intensive survey conducted in 2009 and 2010 confirmed the absence of M. chitwoodi. The species M. fallax was still present in greenhouses and heated tunnels, but unheated plastic tunnels or open fields adjacent to the infested greenhouse proved to be free of quarantine nematodes.