Have you ever noticed nuts or acorns with a small round hole through the shell? This is the exit hole created by the white, wrinkled, legless grub that developed inside the nut, the most common one referred to as the “nut weevil.”
Nut weevils attack the developing nuts on the tree during mid summer. The female adult lays her eggs inside, then the hatched larvae feed inside the nut until fall. The larva grows up to 3/8″ in length as it eats the entire contents of the nut, making it worthless.
The fully-grown grub chews a perfectly round 1/8 inch hole in the side of the nut and emerges in late fall or early winter. Outdoors, these larvae tunnel into the soil to complete development. They remain in the soil for one to two years before emerging as a new adult weevil to repeat the process.