Why is this? My understanding is that an insecticide has no impact on germination of seed, so I assume you're thinking that if I seed shortly after grubex, then the present grubs will eat the new seed roots? FYI, I see no grubs at present and honestly, every time I've checked the lawn over the last two summers, I've never seen them which is why I thought the damage was caused by chinch bugs. Those, I have seen in the past, but to be sure I thought putting down grubex would be ok. There's no way I'm seeding in July, so if I have to wait several weeks after grub tx, then I might as well wait till Fall, which I'd rather not do unless absolutely necessary.