گزارش سه گونه از جنس Discotylenchus Siddiqi, 1980 جمع‌آوری شده از خاک فراریشه درختان زالزالک جنگلی شهرستان خرم‎‎آباد

In order to identify the plant parasitic nematodes fauna of Hawthorn forest trees (Crataegus aronia), during the years 2017-2019, 70 soil samples were collected from root zone of forest hawthorn trees of Khorramabad district, Iran . The soil samples transferred to the laboratory and soil nematodes were extracted adopting Whitehead and Hemming using De Grisse (1969) method ,and their permanent slides prepared . Using light microscope equipped with Dino-Eye Eyepiece Camera digital lens, the morphological and morphometric characteristics of nematode specimens were studied and they were identified at the level of species, using scientific identification keys and resources. In this study, three species namely, Discotylenchus sp., Discotylenchus lorestanensis Mehrabian et al., 2017 and Discotylenchus discretus Siddiqi, 1980 were isolated and identified. Morphometerical and morphological studies showed that Discotylenchus sp. is clearly distinct from all known species of Discotylenchus, having four longitudinal lines with two outer crenate lines, the head disc is somewhat distinct and attached to head base, the excretory-secretory pore behind the terminal bulb, narrow and short tail with a sharp tail end. The morphological results were verified by molecular studies of D2-D3 28S rDNA fragment sequencing,so Discotylenchus sp. is reported as a new nematode species for the first time in the world, , from the root zone soil of Hawthorn trees of Shabankosh village of Sepiddasht region of Khorramabad district, Iran