Selectivity and efficacy of herbicides applied on barley for weed control

Abstract

Ryegrass and turnip are weeds that cause high yield losses when infesting barley, thus requiring adequate management. In this context, the aim of this study was to evaluate the selectivity of different herbicide treatments and weed control in the barley crop, cultivar BRS Cauê. Two field experiments were conducted in randomized blocks, with four replications. The treatments used were: pendimethalin (800 g•ha -1 ), sulfentrazone + diuron (175 + 350 g•ha -1 ), and imazaquim (150 g•ha -1 of a. e.) applied pre-emergence; and iodosulfuron (3.5 g•ha -1 ), pyroxsulam (18 g•ha -1 ), metsulfuron-methyl (3.96 g•ha -1 ), 2,4-D (670 g•ha -1 of a. e.), clodinafop-propargyl (48 g•ha -1 ), bentazon + imazamox (600 + 28 g•ha -1 ), saflufenacil (49 g•ha -1 ), bentazon (720 g•ha -1 ), carfentrazone-ethyl (120 g•ha -1 ), and imazamox (42 g•ha -1 ) applied post-emergence, with two controls (one weeded and the other infested). The use of the herbicide imazaquim caused high levels of phytotoxicity in barley. Gas exchange was less responsive to herbicide applications in relation to barley phytotoxicity and productivity.Clodinafop-propargil showed the best control of ryegrass, while the herbicides iodosulfuron, pyroxsulam, metsulfurom-methyl, 2,4-D, bentazon + imazamox, saflufenacil, bentazon, carfentrazone-ethyl, and imazaquim showed high efficiency in the control of turnip species. Imazaquim caused reduction of up to 74.7% in barley grain yield. On the other hand, iodosulufuron and piroxsulam allowed the highest grain yields of the barley cultivar, BRS Cauê, by promoting partial control of ryegrass and total control of turnip species, followed by clodinafop-propargyl and metsulfuron-methyl, which controlled ryegrass and turnip, respectively, allowing an increase in yield grain in relation to the infested control.

Evaluating the effects of manual hoeing and selective herbicides on maize (Zea mays L.) productivity and profitability

“…two weeks after maize sowing [ 73 ], reported an increase in yield. Similarly, in barley [ 74 ], noted that bentazon applied alone in post-emergence increased yield, but its combination with imazamox was not beneficial. The increase in yield would be associated to its capacity not only to control weeds but also to persist in the soil for the shortest time following photo degradation, which occurs beyond biodegradation [ 65 ].…”

Growth and development of yerba mate seedlings associated with different winter cover species

“…Leaf area of yerba mate plants was reduced when grown in the presence of all weeds evaluated, but significantly in the presence of ryegrass. Ryegrass is not only a plant used for winter cover and forage, but also a weed that attacks crop such as wheat and barley, making it highly competitive (Pies et al, 2019;Galon et al, 2023). On the other hand, the dry matter of the aerial part and roots of the yerba mate was drastically affected by the presence of black oat, which, combined with the reduction in physiological traits, could be due to the greater development of the weed observed due to the greater dry matter of black oat.…”