Before I go and try to remove a Bahia Grass infestation in my turf, I'm wondering if Glyphosate will be effective if I apply it only along the stalk that the seed-head grows out of? There is a lot of surface area as they are 1ft tall.
It's possible and definitely something to test. Glyphosate, from what I read, is supposed to be absorbed through the actively growing portions of the plant. Whether a seed stalk is absorbent enough or not, I can't tell you. My thinking is that it might not be. A seed stalk is meant to be tough enough to stand upright under the weight of the seeds and get them high enough to disperse, while transferring nutrients to grow the seeds. The leaves of plants are designed more to absorb morning dew, which would help them take in the poison.
If you test it and it works, you could try putting the chemical, mixed properly if it's a concentrate, in one of those reservoir handles with a sponge on the end. You can get them for $1 at the dollar store. They're meant to hold dish soap so you can wash your dishes with out having to get more soap. You could load it with your poison, the sponge would load up without dripping, you could tape it to a stick so you didn't have to bend over and then just walk along your problem areas, rubbing the sponge on what you wanted to kill. This might help you target your problem areas without affecting the grass you don't want to harm.
Just remember that when dealing with chemicals, wear protective gear, like rubber gloves or anything else you deem appropriate to safely handle chemicals. I would wear long pants you can wash and real shoes to keep it off your feet, not flip flops. You may walk through where you dispersed it. Also, dispose of all of it appropriately, not where unsuspecting people or animals can come into contact with it. It's serious stuff. Good luck.