Controlling weeds is important not only to maximize the yield potential of a growing wheat crop, but to reduce the difficulty in harvesting the crop, increase the quality of the crop, and reduce the weed pressure in subsequent crops in the rotation.

Many factors affect the potential yield loss from weed infestations, including weed species, weed density, quality of wheat stand, weather conditions, etc. Based on multiple research plots, estimated yield loss for a poor wheat stand can range from 30% with a low weed density to 60% or more for a high weed density. A good stand of wheat can be more forgiving, with an estimated yield loss of 10% for a low weed density, and 40% for a high density. Moderate stands of wheat and moderate weed densities would be expected to fall between those estimates.

The SDSU publication, FS525A, “Weed Control in Small Grain and Millet: 2011” is an excellent guide to the herbicides that are labeled for wheat, other small grains and millet. The information in the publication is based on research by the South Dakota Agricultural Experiment Station and other research and observations. Herbicides are included in the publication only after the product is registered by the Environmental Protection Agency (EPA). Helpful notes are included, as well as restrictions, an estimate of cost per acre, and other information. The publication includes a table of weed and crop response to each herbicide in the document.

Another helpful publication is FS953: “Harvest Aid Weed Control in Small Grain”.