Saponins in Insect Pest Control

Abstract

Insect herbivores are dangerous to all stages of plants, e.g., vegetative as well as reproductive growth, leaves, and shoots. Some of the herbivores feed by sucking plant sap, whereas some insects choose to chew various parts of plants. Thus, all types of herbivores damage plants by feeding directly and cause multiple diseases to plants, leading to plant damage indirectly. However, due to insect attack, plants produce some bioactive compounds (which are known as saponins) to improve their defense mechanism against herbivores. These saponins are further divided into two main categories, i.e., steroidal saponins and terpenoidal saponins. Here, we have highlighted the importance of saponins from multiple plant families against various herbivores. Saponins are present in different wild plants as well as cultivated crops (e.g., soybean, tea, spinach, oat, pepper, capsicum, quinoa, and allium). Some of the saponins play a role as antifeedant while some are insecticidal to different life stages of insect pests. Thus, these saponins play an important role in plant defense against different insect pests. Moreover, different saponins are effective against stored grain pests as well as cosmopolitan insect pests. Therefore, these plant bioactive compounds could be helpful for integrated pest management in different ecosystems.