Pre-emergence herbicide applications are designed to obtain residual activity at the beginning of the crop cycle. The objective of this study was to evaluate the residual activity of diuron, oxyfluorfen, and prometryne, applied alone or in mixture, to control Euphorbia heterophylla. Eight experiments were conducted under greenhouse conditions, by applying herbicide doses or mixtures at 30, 20, 10, and 0 days before weed sowing (DBWS).With diuron and prometryne, satisfactory controls were observed at doses up to 20 DBWS, from 1.07 to 1.6 kg ha-1, respectively. As for oxyfluorfen, a lower residual period was verified, with a minimum gaining control of at least 80% being obtained around 10 DBWS at doses starting from 0.324 kg ha-1. The herbicide mixtures diuron + prometryne promoted more than 85% control for up to 30 days, when applied at the lowest dose (1+2kg ha-1),and 20 days, when applied at 2+1kg ha-1.To obtain the same level of control for 30 days, it was necessary to apply 1+0.288 kg ha-1 of oxyfluorfen + diuron mixture. The prometryne + oxyfluorfen mixture showed a minimum of 80% control within 10 days, when a dose of 1+ 0.192 kg ha-1 was applied.
behavior in soil; herbicide mixtures; persistence
