Milky spore against grubs?

I've read it works but takes years of applications to get levels high enough to do the job.

Please provide a link to this "newer" version of milky spore. I wasn't aware that it changed. The milky spore I know of is used to inoculate the lawn. It was/is expensive to cover the whole lawn. It takes time to spread throughout the lawn so that probably was the reason for any negative effectiveness reports. IIRC, the grubs ingest it, they travel through the earth looking for roots to eat and they die there. The spot occupied by the dead grub is now inoculated with the spores.

Tom

Correct, for that reason one cannot use alternative grub control methods without greatly reducing the efficacy of the milky spore disease. You must allow the grubs to feed on the spore, which can result in large amounts of damage to your turf for years.