Abstract :
Ten organic and inorganic salts were tested for suppression of Fusarium solani, a causal agent of potato dry rot, and silver scurf, a postharvest disease of potato tubers caused by Helminthosporium solani. Ammonium acetate, ammonium chloride, ammonium tartarate, calcium chloride dehydrate, magnesium sulfate, potassium dihydrogen phosphate, potassium iodide, sodium benzoate, sodium bicarbonate and sodium sulphate were added to Potato Dextrose Agar (PDA) at concentrations of 0.1 M, 0.2 M and 0.4 M. Several salts significantly inhibited the mycelial growth, sporulation and spore germination of F. solani and H. solani. The mycelial growth of both tested fungi was completely inhibited by sodium benzoate at the lowest concentration (0.1 M). Sporulation of pathogens was strongly inhibited by sodium benzoate (100%) at all concentrations. Some salts, ammonium chloride, ammonium tartarate, calcium chloride dehydrate, potassium dihydrogen phosphate, potassium iodide and sodium sulphate, increased sporulation of H. solani at the concentration of 0.1 M. Sodium benzoate was also the most effective compound in inhibiting spore germination (100%) for both fungi, followed by potassium iodide (93%) for F. solani and ammonium acetate (88%) for H. solani. Information gathered from this study provides an important basis for further study into the uses of salt compounds for control of postharvest diseases of potato.
