Efficacy of crude aqueous extracts of eight plant species was assessed against Spodoptera litura larvae at 25, 50, 75 and 100 % concentrations alone and in combination with Bacillus thuringiensis sub sp. kurstaki Berliner (Btk) under controlled laboratory conditions. Leaf extracts of Acacia arabica and Annona squamosa were found most promising causing 76.66 % and 83.33 % larval

mortality respectively at 25 % concentration within 3 days of treatment. Leaf extract of Datura stramonium inflicted 93.33 % larval mortality at 50 % concentration within 4 days. When used in combination with Btk, increased larval mortality could be observed vis-à-vis plant extracts alone in cases of seed extracts of A. arabica, A. squamosa and D. stramonium and leaf extract of Pongamia pinnata only on 3 days of treatment and onwards indicating synergistic effect. However, leaf extracts of A. arabica, A. squamosa,D.stramonium, Eucalyptus globulus, Ipomoea carnea, Lantana camara and Nicotiana tabacum had antagonistic effect when used in combination with Btk.