I've spray 24d. But, only with a hand spray. Low pressure early in the morning with no breeze.  Try not to hit the corn leaves.

Lately I've been spraying roundup this way in Sweet corn. If you spray early in the morning, when there is no breeze, and hit the weed just as you notice first leaves. Doing this I spray about a 1% or less solution of 41% Clearout.  I have a hood attachment for my hand sprayer tip.