Effect of host plants pea, okra and lettuce on the efficacy of emamectin benzoate SC 1.5% + indoxacarb EC 7.5% (Penny), Thiomethoxam WG25% (Actara) and lufenuron EC 5 % (Match) against the 1^st inster larvae of Helicoverpa armigera (Hübner) were studied under laboratory conditions. Results showed that the larvae fed on pea treated with penny were more susceptibility followed by okra, lettuce and finally diet. The LC₅₀ values were 0.032, 0.040, 0.072 and 0.274 ppm, respectively. While, the larvae fed on pea treated with Actara was most susceptible followed by okra, lettuce and diet. The LC₅₀ values were 0.074, 0.571, 1.951 and 6.010 ppm, respectively. In case of Match, the larvae fed on okra was most susceptibility and the LC₅₀ values were 0.068 ppm. The order of relative toxicity of different insecticides against H. armigera was maximum in larvae fed on lettuce (27.094), diet (21.934), okra (14.275) and pea (2.813) with Penny, respectively. The larvae fed on treated lettuce with three insecticides was less susceptibility than other two host plants. The used host plants were affected the susceptibility of 1^st instar larvae of H. armigera against different insecticides.