Four corn hybrids were evaluated for tolerance to sethoxydim at 110 and 220 kg ha–1 applied post-directed at two growth stages (V6–7 and V10–11). Dryland corn grain yields did not respond to sethoxydim, while irrigated corn yields were sensitive to sethoxydim treatments. Sethoxydim at 220 g ha–1 reduced the grain yield of hybrid 3377 by 12% at both growth stages. Sethoxydim at the same rate reduced grain yield of hybrid 3379 by 15% when applied to V6–7 corn. Hybrid 3475 had an 11% grain yield reduction from sethoxydim applied at either dosage to V10–11 corn. Under irrigated conditions, a trend toward reduced grain yield was observed for hybrid 3183 at all application times and sethoxydim rates. Corn ear weights and kernel weights differed among hybrids but did not exhibit a response to sethoxydim within hybrids. Visual evaluation for crop injury and measured corn heights did not indicate a response to sethoxydim. There was no yield response in any hybrid to 110 g ha–1 applied to V6–7 stage corn indicating this treatment was safe to use on all hybrids evaluated.
