گزارش گونه های نماتد مولد زخم ریشه در باغات مرکبات شهرستان دزفول و اندیمشک

In order to study the biodiversity of citrus parasitic nematodes, 115 soil and root samples were collected from citrus orchards in northern Khuzestan province during the 2061-2017 years. Nematodes were extracted by centrifugal flotation technique and transferred to glycerin according to the modified De Grisse method. The permanent slides were prepared. The nematodes were identified by light microscopy and drawing tube based on morphological and morphometrical characters .The lesion nematodes rank third behind root-knot and cyst nematodes as the nematodes of greatest economic impact in crops worldwide. This is not only due to their wide host range (more than 400 crop plant species), but their distribution in almost every temperate and tropical environment. Lesion nematodes are migratory endoparasites that feed and reproduce in the root and move around, unlike the cyst or root-knot nematodes, which may stay in one place. Species are distinguished primarily by the morphology of the stylets. In this study، 9 species of pratylenchus were identified including: P. thornei, P. penetrans, P.elamini, P.mediterraneus,.P.silvaticus, P.coffeae, P.pseudofallox, P. acuticaudatus, P.scribneri.. the species P.silvaticus new record for the nematode fauna of Iran. it is characterised by: labial region with two annuli, males common, spermatheca round , female tail tapering with crenate terminus , irregularly striated. it can be distinguished from the closely related species P.flakkensis , P.stoniensis and P.gibbicaudatus by the smaller stylet length , posterior of position vulva and different tail shape . it has only been recorded from the type locality , from around sphagnum at borki, poland. This is the second report in the world.