Is it normal for chestnuts to have worms?

Are Wormy Chestnuts Normal?

If you have ever cracked open a freshly harvested chestnut only to find an unwelcome guest inside, you are definitely not alone. Chestnut producers and consumers frequently run into this issue during harvest season, making it one of the most common complaints in the orchard community.

The culprit behind these tunnels isn't actually a worm at all, but rather the larva of a chestnut weevil. Specifically, these tiny pests usually belong to one of two species: the small chestnut weevil or the large chestnut weevil. During the growing season, adult female beetles pierce the developing shells to lay their eggs deep inside the nut.

By the time autumn rolls around and the chestnuts drop to the ground, the larvae have hatched and begun feeding on the nutritious kernel. While it can be frustrating to find them, this natural phenomenon is a regular challenge in chestnut management. Farmers often use flotation tests—dropping harvested nuts into water—to easily separate the damaged, floating nuts from the healthy ones before roasting or selling them.