I can't ID a grub species offhand, but hopefully somebody can.

I also tried Milky Spore, it didn't work well for me. In my case, I ended up having to pull out the big guns in September to get rid of them--the turf was floating!

I know that nematodes are available that will kill grubs. I'm pretty sure (I've never used them) that the soil has to be pretty damp and kept damp while they work. The nematodes use the water to move around, and die if it goes dry.

That might be the first thing to try. If it works, great. If not, you can re-evaluate at that point.

From what I understand, milky spore takes a few years to fully work. Try putting down another round on the infested area.

I bought my Milky Spore at the Home Depot last year, but it looks like they only carry it online now.

I'm interested in the nematodes, I'll have to see if anywhere around here carries them.

On a related subject I was just checking the grubs' progress across my lawn and happened upon a weird cluster of litter white worms (see pic) any idea what they are?

No clue here, but they are kind of cute and very interesting!