Field efficacy of Bacillus thuringiensis var. kurstaki in combination with plant oils on pest complex of cauliflower

Btk 0.2% + neem oil (Azadirachta indica) 5%; Btk 0.2% + citronella oil (Cymbopogan winterianus) 5%; Btk 0.2% + karanj oil (Pongamia glabra) 5%; Btk 0.2% + cotton seed oil (Gossypium hirsutum) 5% and Btk 0.2% + sesamum oil (Sesamum indicum) 5% were efficacious against Spodoptera litura, Plutella xylostella, Crocidolomia binotalis on cauliflower compared to Bt alone; Btk 0.2% + neem oil 5% was found to be the most efficacious against three lepidopteran pests and resulted in the highest curd yield of 4886.6 kg ha⁻¹ and all the other treatments were moderately effective against the caterpillar complex and resulted in 4440.0 to 3886.6 kg ha⁻¹. From the cost benefit ratio point of view, Btk 0.2% + neem oil 5% (1: 4.6), followed by Btk 0.2% + citronella oil 5% (1: 2.9) and Btk 0.2% + karanj oil 5% (1: 2.4) were more economical.