The common species of nettle caterpillar is Setora nitens. A study has been conducted to explore the potential of Lantara camara in increasing toxicity of Bacillus thuringiensis used as a biopesticide against Setora nitens, a palm oil pest. The experiment was conducted in factorial design (3x2) arranged using Randomly Complete Design. The first factor was concentration of Lantana camara: 5%, 10%, and 15%. The second factor was the incubation time: 3 and 6 days. All experiments were carried out in triplicates. Parameters analysed include: physical changes of biopesticide, population dynamics of B. thuringiensis, and mortality. The results demonstrated that growth of B. thuringiensis increased after incubation for 3 days, followed by exponential growth phase. It was observed that B. thuringiensis was able to use the leaf of Lantara camara as the nutrition as evidenced by browning of the solution and unique odour of L. camara. The addition of 10% L.camara on B. thuringiensis culture, incubated for 6 days, resulted in highest population of B. thuringiensis and increased mortality up to 47.5 %.