Controlling soybean root rot pathogens using some safe organic compounds

Laboratory and greenhouse experiments were carried out during the summer season of 2023 to study the effect of some safe organic compounds i.e. humic acid (HA), amino acids (AA) and proline for controlling damping-off and root rot diseases compared to Rizolex-T50® Wp as a fungicide. Rhizoctonia solani, Fusarium solani and Macrophomina phaseolina were isolated from naturally-infected soybean fields and identified as a causal pathogen of damping-off and root rot. R. solani exhibited a highest frequent followed by F. solani while M. phaseolina comprised the least pathogen frequent isolates. In pathogenicity test under greenhouse experiment, R. solani isolate No 6, F. solani No 3 and M. phaseolina No 5 were the most aggressive isolates for causing damping-off and root rot diseases. In laboratory experiment, proline and humic acids displayed fungicidal activity against mycelia growth of root rot fungi. The high level of proline (300 ppm) was the most effective followed by humic acid at high level (3000 ppm). In artificially-infested soil with a mixture of pathogenic fungi under greenhouse, Rizolex-T50® Wp exhibited the highest reduction of pre, post-emergence damping-off, root rot and wilt diseases. Morover, from the application trails, the best protection against the causal pathogens of soybean damping-off, root rot and wilt was recorded by prolin at 300 ppm followed by HA at 3000 ppm. Herein, it is suggested that soaking of soybean seeds in proline 300 ppm or humic acid 3000 ppm before sowing could be considered as alternative safe methods for chemical fungicides to control root rot diseases.

Controlling soybean root rot pathogens using some safe organic compounds Keywords:

Soybean , Root rot , Organic compounds , humic acid , Amino acids , Proline