Lectins extracted from chickpea, pigeonpea, garlic and field bean were bioassayed along with snowdrop (Galanthus nivalis) lectin against the neonate larvae of Helicoverpa armigera. The surface of the artificial diet in a glass vial (2 cm diameter and 3.5 cm height) was treated with 100 ml of different lectins, and one neonate larva was released in each vial. Data were recorded for larval weight, pupal weight, larval and pupal period, pupation, adult emergence and sex ratio. Larval weights were slightly greater in diets treated with snowdrop, chickpea and field bean lectins. Percentage pupation was low (<60%) in diets treated with pigeonpea, chickpea (in 60% ammonium sulfate solution) and garlic lectins, whereas adult emergence was low in diets treated with pigeonpea and garlic lectins. Garlic lectin had an adverse effect on the larval and pupal weights of H. armigera but not on the duration of larval and pupal development. Lectins from garlic and pigeonpea can possibly be deployed in transgenic plants in combination with Bt genes to increase the level of plant resistance to H. armigera.