THE EFFECT OF GIANT FOXTAIL (SETARIA-FABERI) PLANT HEIGHT ON CONTROL WITH 6 POSTEMERGENCE HERBICIDES

Field experiments were conducted from 1986 to 1988 to evaluate giant f oxtail control at four plant heights by six POST grass herbicides. Cle thodim, fenoxaprop, fluazifop-P, haloxyfop, quizalofop, and sethoxydim controlled 95% or more of 60-cm giant foxtail all three years at the labeled herbicide application rates. Control of 7-, 15-, and 30-cm gia nt foxtail with fenoxaprop, fluazifop-P, quizalofop, and sethoxydim wa s dependent upon soil moisture conditions at application. Clethodim an d haloxyfop provided the greatest control (89 to 99%) regardless of pl ant height or soil moisture conditions. No herbicide injured soybean. Soybean seed yield with POST grass herbicides was equal to or greater than yield in the hand-weeded plots.