Published online by Cambridge University Press: 12 June 2017
Experiments were conducted in the field and controlled-environment chambers to determine wild oat (Avena fatua L. # AVEFA) control with difenzoquat (1,2-dimethyl-3,5-diphenyl-1H-pyrazolium) as influenced by applications at 4-h intervals during the day. Difenzoquat phytotoxicity was significantly higher in four of the six field experiments when applied at 1300 and 1700 h than at other times and was increased in the other two experiments. Difenzoquat phytotoxicity increased with temperature at treatment in the field experiments. Wild oat control was not increased by 8 h of 28 C before or after difenzoquat application compared to a constant 18 C in controlled-environment chambers. In controlled-environment chambers, wild oat control with difenzoquat was not influenced by the time of application during the day when humidity and temperature were kept constant.