Comparative toxicity of Azadirachta indica A. juss. and Callistemon citrinus D. C. against sugarcane stalk borer Chilo auricilius Dudgeon (Lepidoptera: Crambidae)

Efficacy of Azadirachta indica A. Juss. leaves and Callistemon citrinus D.C. leaves extract were tested against sugarcane stalk borer, Chilo auricilius Dudgeon. The plant extract prepared by sequential extraction method using different solvent like, petroleum, chloroform, methanol, distilled water and acetone at different per cent concentrations were used. Ovipositional behavior of adult moth and hatching percentage of the eggs were recorded using choice method for each fraction of the plant extract. The methanol extracts of A. indica 12.33% eggs/female and chloroform extracts of C. citrinus 13.33% eggs/female were found to be effective, and reduced oviposition as compared to other extracts. At 20% concentration, methanol extracts of A. indica and chloroform extract of C. citrinus gave lowest larval survival (55, 52.33 and 48.66% larval survival) after 24, 48 and 72 h of exposures, respectively. However, petroleum ether extract of A. indica at 8, 10 and 20% concentration survival of three days old eggs were registered at 60, 55 and 52%; whereas chloroform extract of C. citrinus at similar concentration recorded 70, 64 and 61% survival.