Assessment of arbuscular mycorrhizal fungi (Glomus spp.) as potential biocontrol agents against damping-off disease Rhizoctonia solani on cucumber

Damping-off disease, caused by the fungus Rhizoctonia solani, is one of the most important diseases of cucumber plant and causes significant yield losses. R. solani possess some characters, such as wide host range and unlimited survival in soil, that make it as pathogen one of the most difficult agents to control. Therefore, the research for finding a biocontrol agent against this disease will be valuable. Two species of mycorrhizal fungi Glomus mosseae and Glomus clarum were evaluated against R. solani on cucumber plants. Mycorrhiza inoculated plants with both species showed a significant reduction in disease severity (DS), 21% and 25%, respectively, whereas the disease severity was 65% for non-inoculated plants. Furthermore, the effects of mycorrhizal fungi were evaluated on growth parameters of cucumber plants. Plants inoculated with both species of mycorrhizal fungi showed a significant increase in both shoot dry weight and root dry weight compared with noninoculated plants. It is concluded that both mycorrhiza species could be an important tool to control some soil-borne pathogens, increase plant nutrients absorption and increase resistance to abiotic stresses.