Potato roots heavily infested by the potato cyst nematode.

Here: white females are visible sticking almost entirely out of the roots, only their heads attached in site the root cortex. Brown patches represent the migratory tracks, because the juveniles move intracellular when invading and migrating through the root, leaving behind a track of dead cells.

Picture: Hein Overmars

Females of potato cyst nematode on root of potato.

Picture: By Hein Overmars