Testing Control Options for Western Salsify (Tragopogon dubius) on Conservation Reserve Program Lands

Abstract

Western salsify has recently formed dense stands in Conservation Reserve Program (CRP) lands in north-central Montana. Our objective was to test the effects of various herbicide treatments and mowing on western salsify and associated vegetation in CRP lands. Six herbicide treatments and one mowing treatment were applied at three sites in 2010. Herbicide treatments included combinations of glyphosate, 2,4-D, dicamba, and/or metsulfuron-methyl applied when western salsify was either in the rosette or early flowering stage. Mowing was applied at the early flowering stage. Herbicide treatments reduced western salsify and increased perennial grass at one of the three sites, which was the site most dominated by western salsify. When dicamba (0.14 kg ae ha−1) plus 2,4-D (0.48 kg ae ha−1) was applied at the rosette stage, western salsify adult plant density and biomass were reduced to zero and perennial grass biomass increased by 108% in 2010. In 2011, western salsify adult plant density was lower across all herbicide treatments compared to the mowed and nontreated plots. Annual grass density increased by up to 400% when herbicide applications including metsulfuron-methyl were applied at the early flowering stage. Mowing did not control western salsify. Results suggest dicamba plus 2,4-D applied at the rosette stage can provide effective control of western salsify and increase perennial grasses without stimulating the emergence of annual grasses.