ABSTRACT
This chapter identifies taxonomic problems which can be most effectively resolved by molecular techniques, and summarizes the available data and literature. It examines molecular methods and also identifies which techniques would practically answer these taxonomic problems. The chapter assesses the comparative utility of these techniques, the taxonomic level at which each operates, and the most profitable future avenues of research. The major role for molecular techniques in entomopathogenic nematode taxonomy is the identification of sibling species, subspecies, and other intraspecific groupings. In the Rhabditoidea, entomopathogenic nematodes form the two families Steinernematidae and Heterorhabditidae, each family with one genus: Steinernema and Heterorhabditis, respectively. Deoxyribonucleic acid sequence analysis is the method of choice for, and may be the only method capable of, discriminating between infrasubspecific categories of entomopathogenic nematodes. Classical morphological methods have been successfully applied to the description, identification, and classification of entomopathogenic nematodes to genus and species.
