Selectivity of Nicosulfuron at Three Popcorn Growth Stages

This work aimed to evaluate the selectivity of the herbicide nicosulfuron toward popcorn (hybrid A 448 White), applied at three growth stages. The experiment was arranged in a randomized complete block design, with four replications. The treatments were organized as a factorial combination, including five nicosulfuron doses (0; 17.5, 35, 70, and 140 g ha(-1)), and three growth stages (V3, V5, and V7), totaling fifteen treatments. The response of the hybrid to nicosulfuron was evaluated in terms of visual injury ratings and effects on plant height at 7, 14, and 28 days after application, yield components (plants m(-2), cob m(-2), cob length, 100 grains weight and kernels/cob), and final yield. In general, hybrid A 448 White showed a higher level of tolerance to the treatments applied at the V3 stage. Grain yield did not suffer significant interference of nicosulfuron at the V3 and V5 growth stages, even at the highest dose. Thus, at the dose range evaluated, nicosulfuron can be used safely at the V3 and V5 growth stages, without risk of reduced yield.