Intercropping insect repellent plants (irps): a promising strategy for sustainable pest management

In current intensive crop production, the utilization of natural biological control in pest management is not fully maximized, resulting in a significant dependency on the application of insecticides. Insect-repellent plants (IRPs) have become a prominent subject of research and a widely implemented strategy for reducing both pest damage and reliance on chemical insecticides. In this study, intercropping three IRP species, coriander (Coriandrum sativum L.; Apiaceae), celery (Apium graveolens L.; Apiaceae), and bunching onion (Allium fistulosum l.; Amaryllidaceae), in two intercropping systems were assessed for controlling insect pests in chilli pepper. The research was carried out in the experimental field of the Indonesian Vegetable Research Institute (IVegRI) in 2022. The results revealed that intercropping systems of chilli pepper with coriander, celery, and bunching onion significantly reduced plant damage over sole crops. Among the various intercrop combinations, chili pepper intercropped with coriander resulted in the lowest damage of three major pest species on chili pepper, Thrips parvispinus (51.77%), Helicoverpa armigera (47.67%), and Bactrocera dorsalis (40.35%). Furthermore, this effect enhanced the productivity of chili pepper yield (43.27%).