A study of interaction between Verticillium wilt Verticillium dahliae and root-knot nematode Meloidogyne javanica in olive cultivars.

Second stage juvenile (J2) of root-knot nematode, Meloidogyne javanica, and microsclerotia of verticillium wilt, Verticillium dahliae, were used as the source of inoculum for nematode and fungus respectively. One-year-old seedlings of olive cultivars, Zard, Roghani, Koroneiki and Manzanilla, were transplanted to pots containing 2000g of sterilized sandy loam soil. Experiment was conducted in completely randomized design with 32 treatments and five replications. Treatments were as follows: control, nematode alone, fungus alone and fungus + nematode. Pots were inoculated with (0, 2000, 3000, 4000) J2 of nematode and/or (10 no/g soil) microsclerotia of fungus according to the treatments. Experiment was terminated after 10 months and fallowing parameters were determined i.e., fresh weight of root and stem, number of galls and egg masses per root system, and percentage of incidence of symptom on aerial parts, browning of vascular tissue, decrease of seedling height and stem/root tissue colonization by fungus. Results showed that presence of nematode caused reduction on colonization of the fungus in the root and stem and vice versa i.e. presence of fungus caused reduction on number of galls and egg masses produced by the nematode. Severe fungus wilt on aerial parts of Manzanilla cultivar was observed when both pathogens were inoculated and mild fungus wilt was observed in fungus alone treatments of Koroneiki cultivar. Galling and egg mass production in root system were reduced in cvs Manzanilla, Zard, Roghani and Koroneiki, respectively (p < or = 0/05). Based on the results obtained in this study, verticilliosis symptoms and galling of nematode in olive seedlings were be less on cvs Koroneiki, Roghani, Zard and Manzanilla, respectively (p < or = 0/05).