Development of entomopathogenic nematodes (Rhabditida: Steinernematidae; Heterorhabditidae) in the desert subterranean termite Heterotermes aureus (Isoptera: Rhinotermitidae)

In laboratory bioassays Steinemema riobrave Cabanillas, Poinar and Raulston (355 strain), S. carpocapsae (Weiser) (Mexican 33 strain), S.feltiae (Filipjev) (UK76 strain), and Heterorhabditis bacteriophora Poinar (HP88 strain) infected and killed the subterranean termite, Heterotermes aureus (Snyder). Steinemema carpocapsae, S. riobrave and H. bacteriophora successfully reproduced in H. aureus and infective juveniles (IJs) exited the termite cadavers successfully. However, no progeny were produced by S.feltiae. IJs of S. carpocapsae formed two distinct size groups. The average total body length for the smaller group was 299.5 μm (S.E. 4.8), the average total body length for the larger group was 545.6 μm (S.E. 6.0). Small S. carpocapsae IJs infect, reproduce and form normal size IJs after subsequent infection in Galleria mellonella L. S. riobrave and H. bacteriophora showed a more gradual recovery in IJ size that needed 2 infection cycles in G. mellonella. In termite mortality tests, the progeny of small IJs of S. carpocapsae are comparably effective to the normal size IJs, under the conditions tested. After 72-h S. riobrave IJs from stock cultures (reared in G. mellonella) caused higher termite mortality compared with IJs cycled through termites then G. mellonella, then applied to termites.