Bioefficacy of Entomopathogenic Nematodes, Steinernema carpocapsae and Heterorhabditis indica Against Third Instar Larvae of Spodoptera litura

The median lethal concentrations (LC50) of H. indica (10.8, 13.8, 23.8 and 15.7 IJs/larva) were lower than those of S. carpocapsae (13.8, 15.9, 28.8 and 19.4 IJs/larva) in sand, red and black soils at 10% moisture and also at 15% moisture in black soil, respectively after 48 h of post infection in third instar larvae of S. litura. The pathogenicity of H. indica was quicker with lower median lethal times (LT50) (55.9–31.8, 66.3–33.1, 80.7–31.6 and 81.0–31.1 h) compared to S. carpocapsae (64.2–33.2, 69.3–35.5, 83.5–32.8 and 86.6–35.4 h) in the dosage range of 5–30 IJs/larva in sand and red soils, 10–50 IJs/larva in black soil at 10% moisture and 5–35 IJs/larva in black soil at 15% moisture, respectively. The pathogenic effects of the test EPNs were better in sandy soil followed by red soil both at 10% moisture, black soil at 15 and at 10% moisture.