Bio-efficacy of pre-and post-emergence herbicides for weed management in Japanese mint (Mentha arvensis)

Abstract

A field experiment was conducted during the summer season of 2014 and 2015 at Kumarganj, Faizabad, Uttar Pradesh, to evaluate the effect of different herbicides on growth and yield of Japanese mint (Mentha arvensis L.) and associated weeds. The experiment was conducted in a randomized block design with 3 replications. There were 10 treatments, comprising pendimethalin 1,000 g/ha, oxyfluorfen 200 g/ha, oxyfluorfen 250 g/ha, pendimethalin 1,000 g followed by (fb) clodinafop 60 g/ha, pendimethalin 1,000 g fb imazethapyr 50 g/ha, pendimethalin 1,000 g fb clodinafop 60 g fb imazethapyr 50 g/ha, metribuzin 490 g/ha, metribuzin 700 g/ha, weed- free, and weedy check. The soil was silt loam in texture with low organic carbon, nitrogen, phosphorus and me- dium in potash. The Japanese mint variety Kashi was used @ 400 kg/ha in rows, 45 cm apart. Application of pre- emergence (PE) pendimethalin 1,000 g/ha and post-emergence (PoE) of clodinafop 60 g/ha followed by imazethapyr 50 g/ha resulted in the highest weed-control efficiency (83.69%) at harvesting stage. Post-emer- gence application of imazethapyr 50 g/ha resulted in 8090% control of broad-leaf weeds, but it produced toxic ef- fect on the crop. Among the weed-control treatments, pendimethalin 1,000 g/ha as a PE fb PoE of clodinafop 60 g/ ha, exhibited higher benefit: cost ratio 2.60 over the other treatments, which proved to be more remunerative and economical to the farmers.