Meloidogyne spp.
Root-knot nematodes
  • Damage to vegetables.   Root-knot nematodes are very damaging to carrots, and are pests of numerous other ornamental and vegetable crop plants.  As the roots are compromised, infested plants are very susceptible to drought.
  • Biology.   Juveniles penetrate host roots where they establish a feeding site. As they develop they develop into females, they cause root swellings (root-knots). The female is usually pear-shaped, with a fragile white cuticle, and may be up to 2 mm in diameter.
  • Ecology.  Root-Knot nematodes are distributed world-wide.
  • Symptoms.  In general, localized areas of stunted plants. Infected carrots are typically forked and malformed. Numerous knots can be found on the tap root and secondary roots.  Strawberry plants look unhealthy and off-color; roots have large or small galls. Infected tomato plants are stunted and produce little or no fruit. They wilt conspicuously in warm weather.
  • Damage to other crops.   Meloidogyne species are also damaging pests of potato and sugarbeet. 
  • Control.  Crop rotation with a non-host such as corn is effective.  For infested home gardens, interplanting or rotating with marigolds will help to suppress populations.  Chemical control can also be effective.
  • Links and References.   Root-knot nematode on carrots.