Chemical control of glyphosate-resistant volunteer maize

Abstract

With the introduction in national agriculture of corn hybrids resistant to glyphosate herbicide, weed management, especially grasses, it was favored. However, volunteer maize plants coming from grains lost in mechanized harvesting can cause significant losses in crops subsequently sown, which has often been soybeans. Thus, the aim of this study was to evaluate the effect of different herbicides in controlling volunteer maize plants resistant to glyphosate herbicide. The experiment was conducted in the Brazilian municipality of Nova Xavantina, MT, between July and September 2014, in an area with a center pivot-type irrigation system. Grains of the F2 generation of AG 8061 VT PRO2^® hybrid were used for assessments. The experimental design was randomized blocks with four replications. The treatments consisted in the application of thirteen different herbicides: haloxyfop-p-methyl 54 g a.i. ha^-1; tepraloxydim 87.5 g a.i. ha^-1; cyhalofop-butyl 247.5 g a.i. ha^-1; fluazifop-p-butyl 156.25 g a.i. ha^-1; sethoxydim 207 g a.i. ha^-1; fenoxaprop-p-ethyl 96.25 g a.i. ha^-1; chlorimuron-ethyl 15 g a.i. ha^-1; imazethapyr 100 g a.i. ha^-1; carfentrazone-ethyl 45 g a.i. ha^-1; fomesafen 237.5 g a.i. ha^-1; saflufenacil 35 g a.i. ha^-1; flumioxazin 60 g a.i. ha^-1 a and paraquat 450 g a.i. ha^-1, in the V3 growth stage of maize and a control without application. Herbicides paraquat, haloxyfop-p-methyl, tepraloxydim, cyhalofop-butyl, fluazifop-p-butyl, sethoxydim, fenoxaprop-p-ethyl and imazethapyr were efficient in controlling maize plants resistant to glyphosate herbicide. These herbicides did not show satisfactory efficiency: chlorimuron-ethyl, carfentrazone-ethyl, fomesafen, saflufenacil and flumioxazin.