Wet conditions over the past couple years have resulted in greater populations of foxtail barley, a very difficult weed to control in no-till wheat. Although foxtail barley flourishes in wet, alkaline soils, it can also spread over an entire field. It is difficult to control because it is a clump-type perennial that grows rapidly in the spring and matures relatively early, often around the end of May or early June. After its first year of growth, it can be nearly completely tolerant to all small grain herbicides registered in South Dakota.
Foxtail barley can be easily confused with quackgrass because they are both perennials and both have auricles, or small finger-like appendages, clasping the stem at the leaf collar. You can differentiate the two by pulling up the weed and inspecting the roots. Foxtail barley will have slender fibrous roots whereas quackgrass will often have a thick reproductive root, called a rhizome, which may have small shoots emerging from nodes along the root.
Since older foxtail barley plants are extremely difficult to control with selective herbicides, it is critical to control this perennial with glyphosate (e.g. Roundup) prior to planting no-till spring wheat or in the fall prior to planting winter wheat. This weed can sometimes persist through corn or soybean rotations if glyphosate was applied late while the foxtail barley was near maturity, so control this weed early in these crops to prevent high densities in rotational wheat crops.
For more detailed herbicide recommendations, refer to “Weed Control in Small Grains: 2012."