Allelochemicals as biocontrol agents: Promising aspects, challenges and opportunities

Agricultural productivity is stricken by abiotic and biotic constraints. The global population is rising continuously, intensifying the pressure on crop productivity. An increase in pest populations, plant pathogens and invasive plants due to climate-related changes can cause significant reductions in yields on arable land. The excessive use of synthetic pesticides has triggered environmental pollution thereby, health hazards. Sustainable agriculture is now focused on ensuring global food security through a range of innovative and environmentally friendly approaches for pest control. Crop plants release allelochemicals into the environment by leaching, foliar decomposition and volatilization from different parts of the plant. These phytochemicals can inhibit the growth of weeds and can be toxic to crop pests. The present review focuses on utilizing allelochemicals as biopesticides for the control of pests, pathogens and weeds. It also sheds light on the use of allelochemicals for the production of plant-based pharmaceuticals. Furthermore, the studies on gene regulation for enhancement of allelochemicals and genetic modifications for crop improvement will pave the way for future research on the development of phytochemicals as a potential tool for sustainable agriculture in agroecosystems.