Soltani, N., Mashhadi, R. H., Mesgaran, M. B., Cowbrough, M., Tardif, F. J., Chandler, K., Swanton, C. J. and Sikkema, P. H. 2011. The effect of residual corn herbicides on soybean injury and yield seeded in the same season. Can. J. Plant Sci. 91: 571-576. In rare situations, poor stands of corn are removed and reseeded to soybean later in the spring, even though residual corn herbicides have already been applied. Nine field studies were conducted over a 3-yr period (2005 to 2007) at four locations in Ontario, Canada, to determine the minimum interval for re-seeding to soybean following the application of residual corn herbicides. Five commonly used residual corn herbicide premixes or tankmixes were applied 6, 4, 2 or 0 wk before soybean seeding. The level of injury generally increased as the interval between herbicide application and soybean seeding decreased. Isoxaflutole plus atrazine caused as much as 28% injury and decreased plant stand, biomass and yield as much as 7, 49 and 42%, respectively. S-metolachlor/atrazine and S-metolachlor plus mesotrione plus atrazine caused 0 to 17% injury, but had no adverse affect on plant stand, biomass and yield except for biomass, which was reduced 18% with S-metolachlor plus mesotrione plus atrazine at 0 wk before seeding. Rimsulfuron plus S-metolachlor plus dicamba caused up to 68% injury and decreased plant stand, biomass and yield as much as 18, 56, and 26%, respectively. Dimethenamid plus dicamba/atrazine caused up to 90% injury and decreased plant stand, biomass and yield by as much as 43, 77, and 54%, respectively. Based on these results, corn producers are advised to switch to herbicides that are less injurious to soybean as the spring seeding season progresses. This would allow for reseeding to soybean if it is no longer profitable to re-seed corn due to the late seeding date.