Recently, olive crop improvement has been paid a considerable attention to in Iran, and this is when olive orchards and nurseries are infected by soilborne pathogens. Root-knot nematode, Meloidogyne javanica, and Verticillium dahliae cause considerable damage to olive groves in the northern part of Iran (Golestan Provience). Therefore, a study of the growth of olive seedlings in the presence of these two pathogens was undertaken. Second stage juvenials (1500 per pot) of nematode were employed as the source of inoculum. Conidia (1×106 per ml) and microsclerotia (7200 per pot) were used as the source of inocula for pathogenesis and the experimental studies respectively. Stem cuttings of olive cv. Zard were transplanted to different sets of pots containing 720cm3 of sterilized loamy soil. Treatments were as fallows: control (check), nematode alone, fungus alone, nematode and fungus (simultaneously), fungus two weeks prior to nematode, nematode two weeks prior to fungus. Results revealed that the fresh weight of root, stem height and number of leaves were the highest and the lowest in control, and in simultaneous nematode and fungus treatments, respectively. Number of chlorotic, wilted and necrotic leaves of seedlings were the highest and the lowest in the simultaneous nematode and fungus, and in nematode alone treatments, respectively. Percentages of root and stem discoloration were the highest and the lowest in the fungus alone and in the nematode two weeks prior to fungus. Number of gall (root-knot) were the highest and the lowest in the nematode alone treatment, and the fungus two weeks prior to nematode.
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