Our Lawn Service has treated the Bermuda Grass with the herbiside Ornamec which, following an immediate rain shower, killed off the grass around the weed. They have removed the dead grass, aerated and overseeded, but they did NOT remove the weed itself. I realize it has like a tap root, but I want to dig it up now while I have the chance. Can you please advise?
The "grass" you refer to is not the Bermudagrass, but rather your turf grass (probably a fescue). Right? And the "weed" you refer to is the Bermudagrass. Right?
If this is correct, we're surprised that the Ornamec killed off your good turf. Was this the intention?
If the intention was to kill the Bermudagrass, are you saying that the Bermudagrass is NOT dead? This is actually to be expected. It is very hard to kill selectively in good turf. In order to do so with Ornamec, several applications would be required and probably several growing seasons (years). Here is a link to the product label. See the top of page 6 about Bermudagrass: http://www.gordonsprofessional.com/pdfs/Ornamec170-SL.pdf
Read the label, too, for info about applying before a rain.
We advise controlling Bermudagrass by spraying Bermudagrass with an herbicide containing glyphosate (a systemic that kills virtually everything) and then reseeding.
Ornamec, too, is a systemic herbicide, which means it gets into the system of the plant and goes down and kills the roots/rhizomes , which are extensive in Bermudagrass, as you know.
You can try to dig out the Bermudagrass roots if they are minor, but it is difficult toget every piece. You lawn will probably require repeated applications of Ornamec.