Below is a photo taken February 27, 2006, in Cheyenne County, Kansas. This wheat has a severe mustard infestation.  A few days later, we treated it with Ally Extra, 2,4-D, and dicamba. 
 

severe mustard infestation

The photo below is the same field as above, in a different area, after treatment. This photo was taken on April 10, 2006, approximately 6 weeks after treatment.
The below picture was taken April 15, 2005. It shows untreated tansy mustard in a later stage of development. Compare it to the treated mustard above at about the same time of year.
mustard april 15

All photos by Grace Flying Service