Identification of Aspergillus section Flavi in maize in northeastern China.

Species of Aspergillus section Flavi were isolated and identified in maize samples collected from a wide geographical region in northeastern China. Aspergillus flavus was identified to be the primary species in the population (99%) becoming a potential source of aflatoxin contamination in the region. Isolated A. flavus strains were classified into the S and L strains respectively based on their sclerotia morphology. Among the A. flavus strains identified, L strains dominated over the S strains in the maize samples studied. Both uniseriate and biseriate forms were observed in A. flavus L strain isolates. However, only uniseriate was observed in A. flavus S strain isolates. Microscopic characteristics of L and S strains were observed and reported. Some geographical differences between northeastern China and other countries and regions were discussed. This is the first study on the population dynamics of A. flavus versus A. parasiticus and the L and S strains within A. flavus in maize samples in northeastern China.