Solutions to Some Problems in Aspergillus Taxonomy Using The Scanning Electron Microscope

Summary

Data obtained from a scanning electron microscope (SEM) study of intraspecific and interspecific variation in Aspergilli associated with post-harvest storage are used to resolve some difficulties in species identification and delimitation. Solutions are provided to problems of identifying isolates of Aspergillus flavus, A. parasíticus and A. oryzae, while the status of A. sojae is resolved. The morphological features of both the conidia and ascospores of A. glaucus are evaluated as marker characters and are shown to be equally useful either complimenting one another or acting indepedently. The long-standing, intricate puzzle surrounding A. melleus, A. quercinus and A. petrakii is explained satisfactorily. Finally, mycologists employing SEM techniques are warned of the wide variability that arises from the ontogenetic development of conidia, and cautioned to ensure that micrographs of mature conidia are obtained.