The large dead spots on #6 fairway are still there, why aren't they fixed yet?

     I has been 17 days since the 1st application of a non-selective herbicide to eliminate Bermudagrass on the fairway. The 2nd application was made 4 days ago with the same product. We are also going to make one more application. Why all these applications and waiting periods? Bermudagrass is one of the most difficult grasses to get rid off after it is established and we have to make sure the herbicide treatment has enough time to translocate through as much of the plant as possible. Once we are sure that we have effected enough of the Bermudagrass the dead turf will be removed and sodded with Bentgrass. This is an abrupt process but one that is necessary.