Aspergillus terreus Inhibits Growth and Induces Morphological Abnormalities in Pythium aphanidermatum and Suppresses Pythium -Induced Damping-Off of Cucumber

The study investigated the efficacy of two isolates of (65P and 9F) on the growth, morphology and pathogenicity of on cucumber. tests showed that the two isolates inhibited the growth of in culture. Investigating hyphae close to the inhibition zone showed that the hyphae showed abnormal growth and loss of internal content. Treating with the culture filtrate (CF) of resulted in significant rise in cellular leakage of mycelium. Testing glucanase enzyme activity by both isolates showed a significant increase in glucanase activity. This suggests that the cell walls of , which consist of glucan, are affected by the glucanase enzyme produced by . In addition, Aspergillus isolates produced siderephore, which is suggested to be involved in inhibition of growth. Also, the CFs of 65P and 9F isolates significantly reduced spore production by compared to the control ( < 0.05). In bioassay tests, the two isolates of increased the survival rate of cucumber seedlings from 10 to 20% in the control seedlings treated with to 38-39% when the biocontrol agents were used. No disease symptoms were observed on cucumber seedlings only treated with the isolates 65P and 9F of . In addition, the isolates did not have any negative effects on the growth of cucumber seedlings. This study shows that isolates of can help suppress -induced damping-off of cucumber, which is suggested to be through the effect of and its glucanase enzyme on mycelium.