Selective Efficacy of Culture Media Recommended for Isolation and Enumeration of Fusarium spp.

Abstract

Selective culture media, such as Nash and Snyder medium (NS), dichloran-chloramphenicol peptone agar (DCPA), modified Czapek-Dox agar (MCz), Czapek Dox iprodione dichloran agar (CZID), potato dextrose iprodione dichloran agar (PDID), or malachite green agar (MGA 2.5), have been developed for isolating and enumerating Fusarium spp. from natural samples. However, some of these culture media are not very selective because they allow the growth of many other fungal species. In this study, a comparison of the selective efficacy of these culture media, using different strains of Fusarium spp. (F. anthophilum, F. culmorum, F. dlamini, F. graminearum, F. napiforme, F. nygamai, F. oxysporum, F. proliferatum, F. semitectum, F. solani, F. subglutinans, and F. verticillioides) and natural samples has been carried out. Among the six recommended selective culture media assayed, no statistical differences were detected in colony counts of the Fusarium spp. strains tested, although the colony diameters in MGA 2.5 were significantly lower than in NS, MCz, DCPA, CZID, and PDID media. With natural samples, MGA 2.5 performs as a potent selective medium for Fusarium spp., whereas the other recommended selective media allow the growth of many other different fungal species including Zygomycetes and yeasts.