Light infestations of Johnsongrass can be controlled by wick application of 41% Glyphosate at a rate of one gallon 41% Glyphosate to two gallons of water in the wick applicator. Apply by wiping twice, wiping both directions when the Johnsongrass is at least six inches above the milo. The more Johnsongrass plant above the milo, the better your results will be. Keep wiper speeds below five miles per hour.
Heavy infestations of Johnsongrass in milo may not be equally controlled. Farmland heavily infested with Johnsongrass should be rotated to another crop such as wheat or a Roundup-ready crop.