Eco-friendly approaches for controlling Echinochloa colona in rice ecosystems using natural herbicides

Echinochloa colona, a highly invasive weed, poses significant challenges to rice cultivation globally and is usually managed effectively through chemical herbicides. Conventional chemical herbicides have contributed to environmental degradation and increased herbicide resistance. This study explores the potential of natural herbicides derived from plant extracts as eco-friendly alternatives for sustainable weed management. Ten plant samples, including Calotropis gigantea, Ocimum tenuiflorum and Prosopis juliflora, were collected and their allelochemicals were extracted using Soxhlet extractor with methanol and hexane solvents. The efficacy of these extracts in inhibiting E. colona germination was tested through pot culture and laboratory assays. GC-MS analysis identified key allelochemicals responsible for the phytotoxic effects, leading to the formulation of natural herbicides in the form of Emulsifiable Concentrates (EC). Field experiments were conducted to assess the performance of these formulations in rice ecosystems. Results indicated that pre-emergence application of 50% EC formulation of 10% methanolic extract of Ocimum tenuiflorum + one hand weeding at 25 DAS showed significant reduction in weed density, dry weight, weed index and increase in weed control efficiency, crop yield and highest benefit cost ratio though further optimization is required to improve formulation stability. This study demonstrates the potential of natural herbicides as effective and sustainable tools for managing E. colona in rice fields, providing an alternative to synthetic chemicals. The findings underscore the need for continued research into the development of durable and efficient natural herbicide formulations