Mark VanGessel, Extension Weed Specialist; firstname.lastname@example.org
Herbicides applied to the soil surface require rainfall or irrigation to move them into the soil where the plants will absorb them; or they must be mechanically incorporated (field cultivator). With the lack of rain in most parts of the region over the past two weeks, we can expect reduced control. Some products like atrazine or mesotrione, maybe taken up by the roots and provide some control. But Dual, Harness, and Prowl all need to be absorbed by emerging shoots or do not translocate, so they will not controlled weeds once they emerge. If you have irrigation and your corn herbicides have been applied but you have not received water, you should consider irrigating to activate those herbicides.