Tracking the Feeding Mechanism of Sap-Sucking Insect-Pests Through Electropenetrography (EPG)

Among insect pests of field crops, sap-sucking insects are a major threat to all agricultural commodities. The sucking insect pests damage the crops by sucking the sap thereby weakening the plants, and transmitting several bacterial, fungal and viral pathogens. The electrical penetration graph (EPG) has emerged as a highly valuable tool for analyzing the feeding behavior of sap-sucking insects on a broad range of host plants, examining pathogen transmission, evaluating the efficacy of feeding-restricting insecticides, plant responses to insect attack, and insect morphology and physiology. The EPG generates waveforms that facilitate the observation of probing behavior of the insects, enabling them to gain insights into the mechanisms and extent of underlying feeding. The integration of multiple complementary techniques, including histological analysis, video tracking, electron microscopy, elicitor proteins, and gene editing, has yielded significant advancements in the management of sap-sucking insects. These techniques have provided a deeper understanding of the underlying mechanisms and interactions involved in insect feeding behaviors, offering new opportunities for targeted interventions and improved pest control strategies. The EPG has been employed since the last five decades, yet needs to be investigated at higher levels with modernization. In spite of having a wide application, it still faces certain limitations, challenges, and research gaps that require addressing for enabling the scientists in novel findings. This review paper provides a historical prospect, the applications and technical intricacies of EPG.