Efficacy evaluation of halosulfuron + metribuzin (pre-mix) for broad-spectrum weed control in sugarcane

A field experiment was conducted at the Agricultural Research Station, Navegaon Bandh, Maharashtra, India, during 2022–2023 and 2023–2024 to evaluate the efficacy, crop safety and residual effects of halosulfuron 12% + metribuzin 55% WG (halosulfuron-methyl + metribuzin) (pre-mix) in sugarcane (Saccharum officinarum L.) under semi-arid conditions. In this randomised complete block design experiment, seven treatments, each with three replications, were evaluated, including post-emergence application (PoE) of halosulfuron-methyl + metribuzin (pre-mix), viz. 350, 450 and 550 g/ha; halosulfuron 90 g/ha, metribuzin 350 g/ha manual weeding and an untreated control. Halosulfuron-methyl + metribuzin 450 g/ha gave the best control of grasses, sedges and broad-leaved weeds with 93.03% weed control efficiency after 60 days of herbicide application (DAHA) with highest cane yield which was statistically similar to hand weeding. The halosulfuron-methyl + metribuzin (pre-mix) 550 g/ha caused slight, transient yellowing of lower leaves which disappeared by 21 DAHA, without effect on final yield. No visible phytotoxicity on sugarcane was observed and the microbial populations and soil physicochemical characteristics of the soil after sugarcane harvest were unaffected with halosulfuron + metribuzin (pre-mix) 450 g/ha. There were no adverse residual effects on germination or seed yield of the subsequently grown sesame (Sesamum indicum L.). Thus, halosulfuron-methyl + metribuzin (pre-mix) 450 g/ha was observed as effective and crop safe method for weed control in sugarcane that can avoid the need for manual weeding in sugarcane.