10 years back (woah, was it that long ago) we had SO MANY grubs, I swear, the ground looked like it was moving when you didn't look directly at it. I mean, there must have been millions of them. I felt like Wang Lung in the Good Earth, 'cept it was grubs - not locusts...and I don't live in China.
They massacred the grass. You could pick out the whole clumps of it like it was a bad wig.
Anyway, the good news is that we didn't have the same problem the next year. and the grass came back pretty quickly. Don't forget to treat your sweet trees, like the maples in a month or so when da beetles come-a-callin!