Scanning Electron Microscopy of Cephalic Regions of Heterodera glycines and Three Related Cyst Nematode Species

Abstract

Cephalic regions of second-stage juveniles and white females of the four closely related species, Heterodera glycines races 1-5, H. lespedezae, H. schachtii, and H. trifolii, were examined by scanning electron microscopy. Interspecific and intraspecific variation occurred among the populations, but differences among female cephalic regions could not be used in species identification of the populations studied. Differences in morphology of dorsal and ventral lips and partial head annulation in second-stage juveniles of H. lespedezae, H. schachtii, and H. trifolii may aid in species identification but cannot be used as the sole criteria to identify the species evaluated in this study.