The noctuid, Helicoverpa armigera, is the most important crop pest worldwide. We evaluated the biological activity of soybean trypsin inhibitor and plant lectins against this pest to identify toxin genes for deployment through transgenic plants. Of the seven plant lectins tested, chickpea and snowdrop lectins showed marked antibiotic effects in terms of insect survival and development. Larval survival was lower in artificial diet impregnated with soybean trypsin inhibitor (49%), and snowdrop (64%) and chickpea (65%) lectins compared to untreated control diet (90%). Pupal weight was adversely affected by chickpea lectin (272.6 mg) compared as to untreated control (335.4 mg). Lower pupation and/or adult emernence (<50%) was observed in diets impregnated with soybean trypsin inhibitor and chickpea, snowdrop and peanut lectins as compared to 90% pupation/adult emergence on untreated control diet. Soybean trypsin inhibitor, and lectins from snowdrop, peanut, and chickpea can be considered for deployment through transgenic plants for the management of H. armigera.