Isolation and Identification of Some Biocontrol Fungi and Evaluation of Their Efficacy Against Charchol Rot Disease Caused by Macrophomina phaseolina on Mung Bean

Abstract

This study aimed to isolate and identify Macrophomina phaseolina fungus which was the causal aget of Charcol rot disease on mung bean (Vigna radita Wilczek L) from Elgadisia Governorate in order to isolate, diagnose, and evaluate efficacy of biological control fungal agents isolalated from the rhizosphere of the host plant. The biocontrol agents T. koningii, C. globosum and A. carbonarius were effective in inhibiting the pathogenic fungus under laboratory and greenhouse conditions. Two isolates of M. phaseolina fungal pathogen were identified in most samples of infected mung bean. Pathogenicity tests showed the ability of M. phaseolina to attack the seeds and cause seed rot. Isolates 1 and 2 of the fungal pathogen reduced the seed germination rate to 71.56 and 63.75%, respectively, compared with 86.66% for the control. The results obtained indicated the presence of a significant difference between the two isolates in inducing seedlings damping-off which reached 40% and 30%, respectively, compared with 0% for the control. The disease severity of isolate 1 reached 75.3% and that of isolate 2 reached 63.6%. The inhibitory effect of the fungal antagonists T. koningii and C. globosum varied. A. carbonarius demonstrated level 3 of inhibition to the pathogenic fungus M. phaseolina, whereas C. globosum and T. koningii demostrated inhibitory levels of 2 and 1, respectively. Results obtained also indicated that treatments with antagonistic fungi T. koningii, C. globosum and A. carbonarius increased the growth parameters of the mung bean plant. The antagonistic fungus C. globosum increased the plant height, root fresh and dry weight and chlorophyll content compared with the control. Furthermore, the results showed that treatment with T. koningii increased the mung bean seed germination rate to 100% and decreased disease severity of mung bean charcoal rot disease to 45.88% as compared to 89.86% severity for the contol. Likewise, the other antagonistic fungi A. carbonarius and C. globosum also increased the mung bean seed germination , and decreased mung bean charcoal rot disease severity. Keywords : Charcoal rot disease, mung bean, Macrophomina phaseolina, T. koningii, C. globosum, A. carbonarius.