Carrot Root Knot Nematodes
Meloidogyne incognita, M. javanica, M. hapla, and M. arenaria
On Crops: Carrots and many other vegetable crops. Over 90 species of nematodes are known to use carrots as a host crop.
Worldwide, wherever carrots are grown
Root knot nematodes are tiny 'eelworms' that live in soil and become plant parasites when they use carrot roots as their nurseries. Often nematodes enter carrots through the root tip, and this injury causes the root to fork, sometimes in several directions. As additional nematodes arrive to colonise the root, small feeder roots are destroyed, and irregular galls take their place.
Carrot roots are twisted and deformed, with much forking and the presence of knobby galls on the outside of the roots. Above the ground, new growth slows as nematode pressure increases; infected plants pull easily from the ground.
Carrots are more susceptible to root knot nematodes than any other garden crop. Nematodes are not very active in cool weather, so sometimes winter carrots will be successful even in soils where some nematodes are present. Good crop rotations prevent nematode build-up in many gardens, but root knot nematodes may be unavoidable in sandy soils in warm climates.
Pull up affected carrots and dispose of them in the bin. Mark the area where the troubled carrots grew, and do not grow carrots, celery or okra there again.