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Interaction of glyphosate with postemergence soybean ( Glycine max ) herbicides

1997; Cambridge University Press; Volume: 45; Issue: 1 Linguagem: Inglês

10.1017/s0043174500092420

1550-2759

Julie M. Lich, Karen A. Renner, Donald Penner,

Agronomic Practices and Intercropping Systems

Greenhouse and field experiments were conducted to evaluate the potential for antagonistic or synergistic interactions from tank mixtures of glyphosate plus a selective herbicide applied postemergence. In the greenhouse, glyphosate at 420 g ae ha −1 plus 28% liquid urea-ammonium nitrate (28% UAN) provided at least 89% control of common lambsquarters and common ragweed. Glyphosate at 1,680 g ha −1 plus 28% UAN provided less than 81% control of velvetleaf and less than 75% control of ivyleaf morningglory. Tank mixing bentazon at 1,120 g ai ha −1 with glyphosate at 420 g ha −1 synergistically increased control of velvetleaf. Tank mixtures of glyphosate plus a selective herbicide were predominately additive in control of common lambsquarters, common ragweed, and velvetleaf. Several tank mix combinations of chlorimuron or imazethapyr plus glyphosate plus 28% UAN were antagonistic in control of ivyleaf morningglory. In the field, glyphosate at 840 g ha −1 plus 28% UAN provided at least 88% control of common lambsquarters and velvetleaf in 1994. However, glyphosate at 840 g ha −1 plus 28% UAN provided only 60% control of velvetleaf in 1995. Tank-mixing bentazon or CGA-248757 with glyphosate at 420 g ha −1 increased velvetleaf and common lambsquarters control in 1995. In general, adding chlorimuron, imazethapyr, or thifensulfuron to glyphosate plus 28% UAN did not increase control of common lambsquarters or velvetleaf. Tank mixing imazethapyr with glyphosate plus 28% UAN antagonized velvetleaf control in 1994 and in 1995. The tank mixture of thifensulfuron at 2 g ha −1 plus glyphosate at 420 g ha −1 plus 28% UAN increased soybean injury in the field in 1994. However, tank mixing chlorimuron, imazethapyr, or thifensulfuron with glyphosate plus 28% UAN did not increase soybean injury in the greenhouse or in the field in 1995.