Bioassay Studies on Carbon Dioxide and Oxygen Gas Concentrations against Rice Weevil Sitophilus oryzae (L.) in Storage

The treatments included T1(95% CO₂: 0%O₂), T₂ (90% CO₂: 5%O₂), T₃(85% CO₂: 10%O₂), T₄(80% CO₂: 15%O₂), T₅(75% CO₂: 20%O₂), T₆(70% CO₂: 25% O₂), keeping N₂ gas as constant at five per cent in all the treatments and T₇ untreated check. Results revealed that Cent per cent mortality of S. oryzae was recorded after exposure period of 6, 12, 24 and 36 hrs; with CO₂ concentration of 85, 90, and 95 per cent LC50 of values for adults was 78.22, 73.82 and 71.22 per cent for an exposure period of 12, 24 and 36 hours respectively.