Certified GKH Gardening Expert
As fall moves on, the grubs burrow deeper into the ground. This is why grub treatments do not work as well in late fall. It would be best to wait to apply neem oil until next year. The good news with neem oil is that you do not need to wait until late summer to apply it. It can be applied in spring, as the grubs return to nearer the surface. Neem oil will essentially halt their lifecycle and they will not emerge as adults.