Tolerance of Sweet Corn (Zea mays) to Clopyralid and EF-689

Abstract

Two experiments were conducted. The first experiment compared sweet corn tolerance to clopyralid at 0.2 to 1.1 kg ha-1, EF-689 at 0.07 to 0.6 kg ha-1 and 2,4-D at either 0.3 or 0.6 kg ha-1. Sweet corn tolerated all rates of clopyralid. EF-689 at 0.2 kg ha-1 or greater caused stalk curvature, stunting, and yield reductions. Stalk curvature also resulted from 2,4-D, but not stunting or yield reductions. The second experiment determined the effect of sweet corn genotype and growth stage at application on injury from EF-689. Injury was genotype and growth stage dependent. Stalk curvature was most severe from treatments 6 wk after emergence, whereas the greatest stunting was from treatments at 4 wk. ‘Supreme’ had the least and ‘Maple Sweet’ the most stalk curvature.