Field experiments were conducted in 1991 and 1992 to evaluate corn tolerance to nicosulfuron following in-furrow or surface-band applications of seven soil-applied insecticides. The organophosphate insecticides evaluated included terbufos (15G and 20CR formulations), phorate, chlorpyrifos, fonofos, and DPX-43898, as well as the synthetic pyrethroid tefluthrin. Potential for a nicosulfuron/ insecticide interaction to injure corn was ranked as follows: terbufos 15G = phorate > terbufos 20CR > fonofos. Chlorpyrifos, DPX-43898, or tefluthrin followed by nicosulfuron caused no significant corn injury. Corn injury and yield reduction were greater in corn treated in-furrow compared with surface-band. Soil moisture at nicosulfuron application was more influential in causing corn injury and loss of yield than growth stage of corn at nicosulfuron application.

Field studies were conducted in 1993 and 1994 to evaluate broadleaf weed control in corn with the sulfonylurea herbicide CGA-152005, CGA-152005 was applied at 10 to 50 g ai/ha alone and in combination with 2,4-D, dicamba, or atrazine. No corn injury was observed either year. Metolachlor plus CGA-152005 controlled redroot pigweed, velvetleaf, and common cocklebur 95% or more in 1993 and 1994. Common lambsquarters and ivyleaf morningglory control was dependent on CGA-152005 rate, weed size at application, and growing conditions. In 1994, control of velvetleaf and ivyleaf morningglory with CGA-152005 at 10 or 20 g/ha was less when applied as a tank-mix with atrazine and dicamba compared with when it was applied alone, probably due to antagonism caused by the companion herbicide. Generally, corn yield was related to weed control.