Pathogenicity of Entomopathogenic Nematodes to Sugarcane Internode Borer, Chilo sacchariphagus indicus Kapur (Lepidoptera: Crambidae)

Abstract

The penetration and pathogenicity of five species of entomopathogenic nematodes (EPN), viz., Heterorhabditis indica (isolate LN2), H. bacleriophora, Steinernema giaseri, S. riobrare and S. feltiae to the sugarcane internode borer (INB), Chilo sacchariphagus inilicus (Kapur), were studied under laboratory conditions. Significant differences were observed among mean penetration of the EPNs. The highest penetration (42.2%) was observed for the steinerncmatids, S. glaseri and S. riobrave (28.3%) and the lowest penetration for the two heterorhabditids. H. indica (5.5%) and H. bacteriophora (5.2%). In pathogenicity studies, mortality of the INB increased with increase in dosage. The borer suffered 100 per cent mortality with 40 and 50IJs of H. indica and with 50IJs larva^−1 of S. glaseri. The lowest mortality (10 to 26.6%) of INB was observed at a dosage of 10IJs larva^−1 of all EPNs. H. indica was found to be superior among all EPN species with an LD₅₀ of I4.7IJs larva^−1. The LD₅₀ values for other EPNs were 17.9IJs larva^−1 for S. glaseri, 24.4IJs larva^−1 for H. bacteriophora, 27.5IJs larva^−1 for S. riobrave and 33.1IJs larva^−1 for S. feltiae