Participatory research on management of guinea grass (Megathyrsus maximus) in sugarcane with pre- and post-emergence herbicides

In India, guinea grass (Megathyrsus maximus) is a valuable forage since its introduction during 1793 to increase the forage quality. Lately, it invaded variable environments as weed in crops such as sugarcane and citrus orchards. A total of four participatory research experiments were conducted during spring season using a randomized complete block design with three replications. The objective was to evaluate efficacy of different pre- and post-emergence herbicides to manage M. maximus in sugarcane. The pre-emergence application (PE) of metribuzin 1.4 kg/ha, diuron 1.6 kg/ha, sulfentrazone + clomazone 1.45 kg/ha and post-emergence application (PoE) of 2,4-D sodium salt + metribuzin + pyrazosulfuron-ethyl 2.4 kg/ha and 2,4-D sodium salt + metribuzin + chlorimuron 2.02 kg/ha recorded maximum control of M. maximus at 30, 60 days after application and at harvest. Furthermore, these treatments resulted in significantly higher cane yield and were at par with each other. Multiple cohorts of M. maximus appears in crop up to 5-6 months of planting of sugarcane, and hence, the highest cane yield was observed in weed free, while physical control measures were costly resulting in lower B:C. Thus, this study underscores the importance of integrated weed management practices for the profitable and sustainable control of M. maximus in sugarcane.