Early emerging summer annual weeds, such as kochia and Russian thistle, can be a problem in winter wheat. The most effective treatments have been tank mixes containing a sulfonylurea herbicide in combination with Banvel or Buctril for kochia control, and either Banvel, Buctril, or 2,4-D in the tank mix to control Russian thistle. Fallow Season Weed control in the fallow season is particularly important to allow for maximum moisture recharge of the soil profile. Weed populations during the fallow season can be quite high, with no crop canopy to intercept sunlight and decrease weed emergence and vigor. Atrazine has been cost effective and efficacious in fallow.
Atrazine provides postemergence as well as residual weed control.
Atrazine rates are dependent on soil type, soil organic matter content and crop rotations. Herbicide applications are most effective when applied to vigorously growing weeds. Treatments applied after an occurrence of precipitation will be more effective than an application during dry weather. Apply all herbicide treatments in a tank mix with two different modes of action to prevent selection for resistant weed species. Kochia, in particular, is prone to selection for herbicide resistance due to high genetic variability and short-term seed viability.