The mustard plant below was treated by Grace Flying Service in the 2005 season with Ally, 2,4-D and High NRG-N as topdress. Even though the mustard was large, control was excellent. Please scroll down for more pictures. 

treated mustard plant

Prior to treatment, a small area of the above field was covered with a tarp. Scroll down to see the results.

tarp on field prior to traetment
Below is the tarped area, later in the year. Without treatment, the rest of the field would have been covered with mustard.
tarped area after treatment

 All photos by Grace Flying Service.