Studies on comparative bioefficacy of pre and post emergence herbicide on Onion (Allium cepa L.) bulb crop

A field experiment was conducted during the rabi season of 2023-24 at MPKV, Rahuri, to assess the effectiveness of various weed management practices in onion (Allium cepa L.). The trial comprised ten treatments involving pre- and post-emergence applications of Oxyfluorfen and Pendimethalin, alone or in combination with hand weeding, along with Propaquizafop-based treatments, a weedy check, and a weed-free check, arranged in a randomized block design with three replications. All weed control treatments significantly reduced weed population and dry matter over the weedy check. The weed-free treatment recorded the highest weed control efficiency, lowest weed density, and superior growth attributes, followed closely by Pendimethalin 580 g a.i./ha (PE) plus hand weeding at 45 DAP. Yield parameters such as average bulb weight and total bulb yield were also highest under weed-free conditions, with T₄ emerging as the best among herbicidal treatments. Economic analysis revealed maximum net returns and benefit-cost ratio in the weed-free treatment, while T₄ provided the highest economic gains among herbicides. The study concludes that Pendimethalin 580 g a.i./ha (PE) combined with hand weeding at 45 DAP is the most effective herbicidal strategy for weed suppression, improved growth, and enhanced bulb yield in onion. Multi-season validation is recommended for broader applicability.