identification, determination of abundance and distribution of plant parasitic nematodes in orchards and fields in qom province

abstract in order to identify plant parasitic nematodes associated with orchards in qom province and determining their distribution, 80samples of soil and root were collected from different locations, during spring and autumn of 2011 the samples were washed and nematodes were extracted by centrifugal floatation technique. they were fixed and transfered to glycerin according to the de grissemethod. the permanent slides were prepared from the extracted nematodes and some cross sections were made from different parts of the body.after preparation of slides, morphological and morphometrical characters specimens were studied by light microscope attached to drawing tube and identification of speciesis determinated with purvey perfect description and comparision with initial description and other valid science refrences. in result 28 species belonging to different genera of tylenchida and one species of dorylaimida and were identified and their distribution were determined. results of this survey showed that the most of these and four species belong to the genera of ditylenchus and aphelenchoides respectively that there are in most of orchards. macropostoniaxenoplax, scutylenchusrugosus, pratylenchusneglectus and xiphinemaindexwere found in 62.5, 58.5, 37.5 and 37.5 percent of samples, respectively, and they were the most aboundant species in the fruit trees of the province.