Revista Brasileira De Herbicidas 2002; 3(1): 29-32
Control of Euphorbia dentata with different formulations of glyphosate in transgenic soybean resistant to glyphosate
DOI: 10.7824/rbh.v3i1.368
Euphorbia dentata is a highly competitive and difficult to control weed in soybean crops in the central are a of Buenos Aires Province, Argentina. Development of transgenic soybean resistant to glyphosate (GR) allows exploration of new techniques of chemical weed control, mainly where the herbicides traditionalJy used are inefficient. The objetive of this . research was to evaluate the effectiveness of Euphorbia dentata control with different formulations of glyphosate in soybean GR. The trial was carried out in Azul district, province of Buenos Aires, during the 99/00 and 0010 I agricultural seasons using soybean cv. AX 4100 GR and with an infestation of E. dentata of 135 pl/m” The treatments consisted in the application of three doses of glyphosate (720, 1260 and 1620 g/ha acid equivalent) using three commercial formulations of the same active ingredient available in Argentina: formulation 1 (isopropylanmine salt SL 48%, Ru) , formulation 2 (monoamonic salt WG 74,7%, Ru_M), formulation 3 (isopropylamine salt with transorb technology SL 48%, Ru_F), weeded control and non weeded, where the weeds were removed manually. The sprayings were performed when the weed had developed 4 true leaves and with a volume equivalent to 100 Llha, using a CO2 manual equipment. Weed control and crop yield were evaluated. Ali the glyphosate formulations obtained high levels of control (more than 85 %) with the use ofthe maximum doses but did not differ significantly among themselves. The isopropylamine salt formulation (Ru_F) showed high efficiency even with a doses of 720 g/ha, whereas the other formulations only obtained partial controls (50 and 60%). Concerning yield, ali the treatments differed significantly from the weeded control whose productivity was about 2500 kglha. The treatments which obtained the maximum levels of control did not differ significantly from the control without weeds which had a yield of 4000 kg/ha.
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