ABSTRACT
The term 'entomopathogenic nematode' was first proposed by Gaugler and Kaya (1990) to identify insect-parasitic nematodes that kill their hosts quickly, usually in 48 hours. The 'quick-kill' by the entomo-pathogenic nematodes, represented by the two families Steinernematidae and Heterorhabditidae, is because they serve as vectors for the mutualistic-associated bacteria that are the true pathogens of the insects. The bacteria (Xenorhabdus spp. for steinernematids and Photorhabdus spp. for heterorhabditids) are found in the intestines of the third-stage infective nematode larvae (Kaya and Gaugler, 1993; Forst et al., 1997). The infective larva (IL) infects its host by entering through natural openings (mouth, anus, spiracles) and then penetrating into the insect's haemocoel. The IL of heterorhabditid nematodes also has an anterior tooth that allows it to penetrate through soft insect cuticle directly into the haemocoel. The nematodes develop and reproduce in the insect cadaver by feeding on the bacterial cells and decayed host tissues. Under ideal conditions, the ILs begin exiting from the cadaver from 7 to 15 days after infection and search for new hosts.
