Published online by Cambridge University Press: 12 June 2017
Preemergence and postemergence application of metribuzin [4-amino-6-tert-butyl-3-(methylthio)-as-triazine-5(4H)-one] at 0.6 and 1.1 kg ai/ha controlled downy brome (Bromus tectorum L. ♯ BROTE) in winter wheat (Triticum aestivum L. ‘McDermid’) but caused considerable injury without the use of activated carbon over the seeded row. Activated carbon applied in 5-cm bands over the seeded row at 84, 167, and 336 kg/ha protected winter wheat at Pendleton on a silt loam soil. On a sandy loam soil, only a 336 kg/ha rate provided protection from metribuzin. Metribuzin toxicity to winter wheat was more difficult to neutralize when applied preemergence. Downy brome control was not reduced by carbon applied over the wheat row. The best treatment in this study was carbon at 336 kg/ha applied preemergence over the row followed by metribuzin at 0.6 or 1.1 kg/ha postemergence. A 10-week delay between preemergence carbon banding and postemergence metribuzin protected winter wheat from chemical injury.