Biology of indigenous strains of entomopathogenic nematodes, Heterorhabditis bacteriophora Poinar and Steinernema feltiae (Filipjev) Poinar

The biology of the indigenous strains of entomopathogenic nematodes, Heterorhabditis bacteriophora Poinar and Steinernema feltiae (Filipjev) Poinar was studied on rice moth, Corcyra cephalonica Stainton larvae. The infective juveniles of H bacteriophora penetrated the Corcyra larvae through mouth, anus and spiracles/cuticle. No significant differences in the port of entry ie through mouth, anus and spiracles/cuticle were found. After reaching the insect haemocoel the infective juveniles released their associated bacterium killing the insect host in 24–48 hours. The infective juveniles became parasitic third stage juveniles (L3). The cadaver of the dead host assumed red colour which turned brick red with time. The parasitic L3 gave rise to L4 (pre-adult female) in 24 hours later. In 34 days after infection hermaphroditic females were formed. The hermaphroditic females laid eggs which developed into first stage larvae (L1). L1 hatching from laid eggs developed directly to L4. The adults of second generation were formed in 6 days after infection. Male/female ratio was 1: 6. The eggs from second generation females developed into second stage juveniles (L2) inside the female body. The development of L2 was completed in 9–10 days after infection. The emergence of infective juveniles from host cadaver started after 11–12 days of infection. Two generations were completed in full grown Corcyra larvae. The biology of S feltiae was similar to that of H bacteriophora except for minor differences. The infective juveniles of H bacteriophora developed into hermaphroditic females whereas the infective juveniles of S feltiae developed into males and females. Male/female ratio in S feltiae was 1: 2. The cadaver of S feltiae infected insect assumed yellowish brown colour.