Effectiveness of different adjuvants on efficacy of stellar (topremazone plus dicamba) applied at reduced rates in maize (Zea mays L.)

Abstract

Field experiments were carried out in 2017 and 2018 on two individual farms that grew maize for grain, in Tetovo and Skopje locality, to determine the effectiveness of different adjuvants on the efficacy of Stellar applied at reduced rates. Herbicide treatment selectivity and influence on grain yield were estimated, as well. Both sites were naturally infested with a high population of Polygonum lapathifolium L., Chenopodium album L., Echinochloa crus-galli (L.) P. Beauv. and Sorghum halepense (L.) Pers. Overall efficacy of herbicides in control of weeds 28 DAT was ranged of 77% (Stellar + White oil applied at 0.125 + 0.2 L ha–1 ) to 98% (Stellar + Trend applied at 0.75 + 1.0 L ha–1 ) in Tetovo locality, and 64% (Stellar + White oil applied at 0.125 + 0.2 L ha–1 ) to 99% (Stellar + DASH applied at 0.75 + 2.0 L ha–1 ) in Skopje locality, respectively. In both localities, the efficacy of the full rate of Stellar (90 and 80%, respectively) was on the level of Stellar + White oil applied at 0.25 + 0.2 L ha–1 (90 and 78%, respectively). Herbicide efficacy 56 DAT was similar to the previous period of estimation. Efficacy of herbicide and herbicide plus adjuvants treatments in control of prevailing weeds 28 and 56 DAT ranged from 22–100% in Tetovo locality and 30–100% in Skopje locality, respectively. No visual maize injured was determined by any herbicide treatments in both localities for both years. Maize grain yields for each treatment in both localities generally reflected overall weed control.