Published online by Cambridge University Press: 12 June 2017
SAN 582 at 1.1, 1.2, 1.3, 1.5, and 1.6 kg ai/ha; alachlor at 1.7, 2.2, and 2.8 kg/ha; and metolachlor at 1.7, 2.2, and 2.8 kg/ha were applied preemergence without and with atrazine at 1.7 kg/ha in no-till corn at two locations near Blacksburg, VA, in 1993 and 1994. SAN 582, alachlor, and metolachlor controlled TR-smooth pigweed when applied without or with atrazine, and with only a few exceptions, control was greater than 60%. The highest rate of individual herbicides was more effective than the lowest rate in most cases. Early control of TR-smooth pigweed was similar from all three herbicides, especially at higher rates, but control later in the season tended to be best with alachlor. As expected, atrazine applied alone did not control TR-smooth pigweed, and crop yields were increased with herbicide treatments compared to no treatment.