These herbicides may provide acceptable control when applied early postemergence and tank mixed with a residual grass herbicide. For example, Basis Gold or Accent Gold will control small foxtails, suppress or control emerged large crabgrass and the tank mix partner will control subsequent crabgrass flushes. An early application, preferably before the crabgrass has started to emerge, is very important with this type of program. Herbicides in the Accent family have short residual activity and will not control late flushes of crabgrass alone. With the limitations of the postemergence herbicides in conventional corn hybrids, it is easy to see why soil-applied grass herbicides offer a better control option.
Cultivation is another control option for crabgrass that has emerged in corn.
In fields with conventional hybrids, it may be the only reasonable control option, especially if the crabgrass is taller than two inches. Even when using soil-applied grass herbicides, fields should be scouted for escaping crabgrass and followed with cultivation as necessary. Crabgrass Control Options in Herbicide-Resistant Corn Hybrids Crabgrass can be controlled postemergence with Roundup Ultra in Roundup Ready corn, Liberty in Liberty Link corn, Lightning in IMI corn, and Poast Plus in Poast Protected corn. Roundup Ultra will give excellent control of emerged crabgrass. The label states that crabgrass up to 18 inches tall can be controlled, but it should be controlled much earlier to avoid competition and yield loss.