Efficiency of some herbicides and manual weeding for weed control in irrigated Bt cotton 

To evaluate the efficacy of some pre and post-emergence herbicides for weed control in Bt cotton (var. Beejdhan 2), a field experiment was conducted during rainy seasons of 2014-15, 2015-16 and 2016-17 at Junagadh (Gujarat, India). The dominant weed flora in cotton field were Digera arvensis, Eluropus villosus, Cyperus rotundus, Cynodon dactylon, Echinochloa crusgalli, Chenopodium album, Convolvulus arvensis, Trianthema monogyna, Amaranthus spinosus, Commelina benghalensis and Asphodelus tenuifolius. The results revealed that treatments viz., hand weeding (HW) and interculturing (IC) at 30, 60 and 90 DAS, pendimethalin 0.9 kg ha-1 as pre-emergence fb HW and IC at 30 and 60 DAS, and pendimethalin 0.9 kg ha-1 as pre-emergence fb quizalofop 40 g ha-1 as post-emergence at 45 DAS were found superior to the unweeded check in enhancing growth and yield attributes viz., plant height, number of monopodial and sympodial branches plant-1, number of bolls plant-1, single boll weight and seed cotton weight plant-1 and ultimately increased seed cotton and stalk yields. These treatments also recorded lower dry weight of weeds and weed index along with higher weed control efficiency, net return and B:C ratio as compared to unweeded check.