Effect of Arbuscular Mycorrhizal Fungi on Verticillium wilt development of olive trees caused by Verticillium dahliae

This study reports the effect of Arbuscular Mycorrhizal Fungi (AMF) on olive plants to enhance its tolerance against Verticillium dahliae under greenhouse conditions. Inoculated plants with native mycorrhizal consortium (Rhizolive) or with Glomus irregulare pure strain were treated three months after mycorhization with V. dahliae. It was found that root colonization by Rhizolive or G. irregulare was similar. Results showed that disease severity and percentage of dead plants were significantly reduced in G. irregulare + V. dahliae (1.36 and 20% respectively) compared to Rhizolive + V. dahliae treatments (2.20 and 28.30% respectively). Moreover, compared to controls, lower dwarfing index and leaf alteration index were shown in inoculated plants with Rhizolive + V. dahliae (-9.73% and 0.143 in 21st week); also, in inoculated plants with G. irregulare + V. dahliae (-2.96% and 0.200 in 21st week) treatments. Mycorrhization with Rhizolive or G. irregulare seemed to help olive plants to reduce the disease symptoms caused by V. dahliae.