Nicosulfuron Tolerance in Sweet Corn (Zea mays) as Affected by Hybrid, Rootworm Insecticide, and Nicosulfuron Treatment

Abstract

Sweet corn tolerance to nicosulfuron as affected by interactions between nicosulfuron applied postemergence (POST), sweet corn hybrid, and rootworm insecticide applied at planting was determined in 1992 and 1993 field experiments. Sweet corn vigor was reduced as nicosulfuron rate increased from 35 to 140 g ai/ha. Sweet corn vigor was reduced 4% more by nicosulfuron with oil emulsifier mixture than nicosulfuron with non-ionic surfactant one week after treatment (WAT). Adjuvant selection did not influence nicosulfuron injury to sweet corn 2 WAT. Nicosulfuron applied postemergence directed (PDIR) caused less sweet corn injury than nicosulfuron applied broadcast POST. ‘Jubilee’ sweet corn was more sensitive to nicosulfuron and insecticide treatments than ‘Excellency’ or ‘Green Giant 40.’ Nicosulfuron reduced sweet corn vigor twice as much when terbufos was applied at planting compared to no insecticide at planting. Neither chlorpyrifos or chlorethoxyfos at planting increased sweet corn injury due to nicosulfuron compared to no insecticide. Excellency and Green Giant 40 yields were not reduced by any treatment. Yields were reduced only when nicosulfuron was applied to Jubilee treated with terbufos. Jubilee yield reduction from nicosulfuron and terbufos was prevented by applying nicosulfuron PDIR.