Olive (Olea europaea L.) is the most important and traditional woody crop that cultivated over a large areas in Iran. Olive cultivation has expanded during the last decade especially in Golestan province, the northern of Iran (Figure 1). In this province nearly 10,000 hectare of olive orchards are present, which represents about 20% of total national olive area (Anonymous, 2007). In the last decade most of new plantations in this region established with Rooghany, Zard and Mary cultivars, which are the native olive cultivars of Iran (Sanei et al., 2004). Commercial cultivars of olive are planted in Iran but wild olive are the important genetical sources of olive, that residue of them can be seen in the East of Golestan province, north of Iran (Sanei et al., 2005). Unfortunately, olive is subjected to be attacked with a variety of fungal pathogens which affect its health, yield and its oil quality (Sanei et al., 2012). Young olive especially Rooghany and Zard cultivars showing decline symptoms were observed in several greenhouse. This syndrome was associated with a severe root rot. Several fungal pathogens were consistently isolated from roots of symptomatic seedlings such as Fusarium solani, Macrophomina phaseolina, Phytophthora megasperma and Pythium aphanidermatum (Sanei et al., 2005, 2012). Macrophomina phaseolina (Tassi) Goid is the most fungal pathogens affecting olive cuttings in Golestan nurseries.