Field library

Potato Tuber Moth

A small grey-brown moth whose pink-white caterpillar tunnels into potato leaves, stems and, worst of all, into the potatoes themselves. In the field it gets into any tuber showing through a crack or through bare soil. In the store it keeps breeding, the tunnels fill with dark droppings, and the potatoes rot.

How to scout

Look for silvery mines and dried blotches on the leaves, and dig a few tubers from beside the soil cracks; in the store, check around the eyes of the potatoes for tiny holes with brown dust.