In Vitro Studies of Antifungal Activity of Colloidal Silver against Important Plants Pathogens

Colloids and especially silver are increasingly used in a variety of worldwide applications because of their potential antimicrobial activity and their plasmotic and conductivity properties. This research reports the fungitoxic properties of colloidal silver on mycelial growth of important plant pathogens: Alternaria brassicicola, Botrytis cinerea, Aspergillus flavus, Aspergillus niger, Fusarium culmorum, Fusarium oxysporum, Penicillium digitatum and Sclerotinia sclerotiorum. Although variable responses towards each compound were observed within the species the results revealed a clear reaction to limiting mycelium growth relative to various concentration of Colloidal silver (CS). Results were expressed as effective concentrations which inhibit mycelial growth by 50% and 90% respectively (EC50 and EC90). Efficiency of colloidal silver on mycelial growth inhibition of different isolates based on EC50 have the following values: 3.69 ppm for Alternaria brassicicola, 7.32 ppm for Botrytis cinerea, 18.21 ppm for Aspergillus flavus, 10.43 ppm for Aspergillus niger, 11.99 ppm for Fusarium culmorum, 12.27 ppm for Fusarium oxysporum, 10.82 ppm for Penicillium digitatum and 6.34 ppm for Sclerotinia. According to the obtained results the antifungal activity of colloidal silver particles as biocide has potential for using it as a non-aggressive treatment in horticulture and sustainable horticulture.