Sequential application of diclosulam and cycloxydim for control of mixed weed flora in rabi-summer groundnut (Arachis hypogaea L.)

A field experiment was conducted during winter season (rabi-summer) of 2018-19 at S.V. Agricultural College Campus of Acharya N. G. Ranga Agricultural University, Andhra Pradesh, to evaluate the effect of pre-emergence (pendimethalin 38.7% CS, pendimethalin 30% EC and diclosulam 84% WDG @ 725, 1000 and 20 g/ha, respectively) and post-emergence (haloxyfop-p-ethyl 10.5% EC @ 135 g/ha and cycloxydim 20% EC @ 100 g/ha)herbicides on weed growth and yield of groundnut. The pre-dominant weed flora associated with groundnut was Cyperus rotundus L. (42%), Boerhavia erecta L. (15%), Dactyloctenium aegyptium (L.) Willd. (11%) and Commelina benghalensis L. (9%). Pre-emergence application of diclosulam 20 g/ha supplemented with hand weeding (HW) at 40 DAS or cycloxydim 100 g/ha at 20 DAS resulted in lower density and dry weight of all the categories of weeds including Cyperus rotundus. Pre-emergence application of diclosulam 20 g/ha resulted in phytotoxicity rating of "1" in 0-10 scale with yellowing of young leaves in groundnut and the crop recovered within 25 days after its application. Pre-emergence application of diclosulam 20 g/ha supplemented with HW at 40 DAS resulted in higher yield components and pod yield of groundnut, which was comparable with sequential application of diclosulam 20 g/ha as pre-emergence and cycloxydim 100 g/ha at 20 DAS. However, the former weed management practice obtained higher net returns and benefit-cost ratio than latter. These two weed management practices increased the pod yield of groundnut tby 48.8 and 44.2 %, respectively compared to un-weeded check.