Abstract
Results of Races identification of citrus nematode Tylenchulus semipenetrans revealed that the three isolates of nematode used in this study which belong to Mediteranean race .Histopathological study showed that the effect of citrus nematode extend to various root tissues of sour orange and lemon including cells of the epidermis and cortex as well as gradual breakdown of the cell walls happened and empty of those cells, enlargement of cells located in front of nematode head appeared as a result of that five nurse cells formed in front of nematode head in cortex as well as in endodermis and pericycle.
