identification of plant parasitic nematodes of potato fields in khorasan razavi province

abstract in order to identify the plant parasitic nematodes of potato fields, 55 soil samples and 60 infested tuber samples were collected from different fields in khorasan razavi province during 2005-2006 . soil samples were washed and nematodes were extracted by centrifugal flotation technique. according to de grisse, the extracted nematodes were fixed and transferred to glycerin. baermann funnel method was used for extracting nematodes from tuber samples. in this survey, 16 species belonging to 12 genera of infra order tylenchomorpha were identified based on morphological and morphometrical characters. aphelenchoides brassicae is new record from iran and helicotylenchus indicus was collected from potato fields and rhizospher rosmarinus officinalis in campus of ferdowsi university of mashhad at the same time. pratylenchus neglectus, geocenamus rugosus, heterodera schachtii, heterodera trifolii and zygotylenchus guevarai were the most frequent and dominant species.