Evaluation of antifungal activity of sulfur-containing salts against phytopathogenic fungi

Abstract

The efficacies of sulfur-containing salts (ammonium sulfate, magnesium sulfate, potassium metabisulfite, potassium sulfate, sodium metabisulfite and sodium sulfate) were evaluated as possible alternatives to synthetic fungicides for the control of economically important phytopathogenic fungi, including Fusarium culmorum, F. nivale, F. solani, Macrophomina phaseolina, Rhizoctonia solani, Sclerotinia sclerotiorum, Puccinia triticina and Uromyces appendiculatus. The results, including the concentration of salts that caused a 50% reduction (ED50), the minimum inhibition concentration (MIC), and the minimum fungicidal concentration (MEC) values for mycelial growth, spore germination and germ-tube elongation, indicated that sodium metabisulfite, potassium metabisuffite and ammonium sulfate were more toxic to the tested fungi than the other salts. Therefore, sodium metabisulfite and potassium metabisulfite were selected for further testing in soil. Both sodium metabisulfite and potassium metabisulfite completely inhibited the mycelial growth of S. sclerotiorum at 0.2% in soil tests. However, they were able to stop mycelial growth of F. culmorum, F. nivale, F. solani, M. phaseolina and R. solani at only 0.4%. In pot experiments conducted under controlled conditions, foliar sprays of salts at all the concentrations tested except 0.05% were effective on the control of rust fungi (P. triticina and U. appendiculatus). In these experiments, control efficacy of all tested salts ranged from 0 to 90.3% and 0 to 94.9% against P. triticina and U appendiculatus, respectively. Sodium sulfate at 1.5% and Mancozeb treatments equally and effectively reduced the pustules caused by P. triticina and U appendiculatus. The results of this study showed that the sulfur-containing salts tested could be used for control of phytopathogenic fungi.