Comparison of two selective culture media for the detection of Fusarium infection in conventional and transgenic maize kernels.

To assess differences between two recommended selective culture media, Nash and Snyder medium (NS) and malachite green agar 2.5 (MGA 2.5), for the detection of Fusarium infection in conventional and transgenic maize kernels. In total, 10 800 kernels from commercial varieties grown in Spain were analysed using these Fusarium selective culture media. Fusarium verticillioides was predominant in both selective culture media. Mean percentages of Fusarium infected kernels were significantly lower in transgenic maize kernels than in conventional maize kernels. There were no significant differences in percentage of Fusarium infection between the two selective culture media used, although the total mean value on MGA 2.5 (18.8%) was slightly lower than on NS (19.1%). MGA 2.5 performed as a potent selective medium for the detection of Fusarium infection in maize kernels using the direct plating technique. NS with pentachloronitrobenzene (PCNB) as fungal inhibitor is one of the most widely employed selective culture medium for Fusarium spp. However, PCNB has been reported to be carcinogenic. MGA 2.5 can be used as an alternative to NS in the detection of Fusarium infection in grain samples using the direct plating technique.