Don't wait until June to kill Bermuda, if small patches, spray roundup 3 weeks apart as soon as Bermuda starts to break dormancy. You can continue to spray during the summer if new Bermuda appears. This is the most effective and cost-effective way to eradicate Bermuda.

You can seed those spots later in the Fall, by Winter, you will have an even green Fescue lawn without brown patches of common Bermuda.

Be sure to add some Kentucky Bluegrass to you Fescue.

When you see June bugs or Japanese beetles swarming your porch lights, then you can apply something for the grubs. Most years you will never see them and you don't need to apply. Normal lawns can handle up to 12 grubs per square foot. Don't apply anything if you have fewer than that.

The only way to kill Bermuda grass short of digging out the yard is Methal Bromide, which is not available to homeowners and will be off the market in a year. You can try all you want with round-up it's going to come back.

As far as the grubs there is a certain time to apply depending what kind of insect you have. If you see them as adult form then its too late, you missed their cycle. Check out some common grub damage and compare to yours and see how best to attack from there. Most grubs have a certain stage that they are susceptable to pesticides and it must be timed just right.

Did you ever figure out what to set your spreader at? I have the same issue.