EFFECT OF SOIL MOISTURE ON THE EFFICACY OF FOLIAR-APPLIED WILD OAT HERBICIDES

In controlled environment experiments, the efficacy of diclofop methyl applied to wild oat was reduced more than the efficacy of difenzoquat or flamprop methyl when the soil water content (SWC) was cycled between −0.24 and −2.18 MPa (low SWC) compared to when it was cycled between −0.03 and −0.06 MPa (high SWC). Similarly, at low SWC diclofop methyl was much less effective than either fluazifop-p-butyl or sethoxydim in reducing the post-treatment dry weight accumulation of the weed.Key words: Oat (wild), soil moisture, diclofop methyl, flamprop methyl, difenzoquat, fluazifop-p-butyl