There are small, round holes in many of the acorns on the ground. What made the holes?
The small, round holes on the sides of the acorns were likely caused by the larvae of the acorn weevil.
The adult acorn weevil is a brown beetle about 3/8 inch in length and has a long, thin snout. Adult females lay their eggs inside developing acorns on trees in mid-summer. The eggs hatch into creamy white, grub-like larvae that feed inside the acorns until fall. In fall when the acorns have fallen to the ground, the fully grown grub chews a round 1/8 inch hole in the side of the acorn, exits the acorn, and tunnels into the soil to complete its development.
Squirrels and other wildlife eat or stash away the good acorns, leaving the “holey” (destroyed) acorns on the ground.