The symptom of root knot is galls on carrot feeder roots and forking. The gall size can vary depending upon nematode species and severity of infection.

Stunting and yellowing of plants can be seen along affected areas in the field. Small galls can be seen on infected plants for early or minor infection situations.

Large spherical galls of an affected carrot feeder root on a severely affected carrot. The galls can also merge to form large galled area throughout the feeder roots.

Forking is common on infected plants and can be mild or very severe. The plant stand tends to be very poor in sections of field with severe infection of root-knot nematodes.