Penetration and Pathogenicity of Entomopathogenic Nematodes to Sugarcane Early Shoot Borer, Chilo infuscatellus Snellen (Lepidoptera: Crambidae)

摘要

Penetration and pathogenicity of seven species of entomopathogenic nematodes (EPN), viz., Heterorhabditis indica (LN2), H. bacteriophora (LN8), Heterorhabditis sp. (HII), Steinernema carpocapsae, S. glaseri, S. riobrave and S. feltiae to sugarcane early shoot borer, Chilo infuscatellus Snellen, was studied under laboratory conditions with bioassay techniques. Significant differences were observed in mean penetration of the EPNs in C. infuscatellus larvae. The penetration rate recorded was highest in S. glaseri followed by S. carpocapsae (29 and 18% respectively), while it was lowest in the three species of heterorhabditids, Heterorhabditis sp. (HII), H. indica (LN2) and H. bacteriophora (LN8). In pathogenicity studies, mortality of the early shoot borer larvae increased with increase in dosage. The larval mortality was 83.3 per cent at the dose of 50 infective juveniles (IJs) of H. indica and S. glaseri. It was least at 10 IJs/larva of all EPNs tested. The LD50 values showed that S. glaseri was superior to all other EPN species (24.2 IJs/larva) followed by S. feltiae (26.6 IJs/larva).