Root Knot Nematode

Meloidogyne spp.

In cool climates:

M. artiellia, M. chitwoodi, M. naasi, M. microtyla.

In warm climates:

M. graminicola, M. graminis, M. kikuyensis, M. spartinae.

In tropical and subtropical areas:

M. incognita, M. javanica, M. arenaria.

  1. Symptoms: Infestations of root knot nematodes are characterized by the formation of small knots or galls near the tips of the roots. Above ground, infested plants are stunted and chlorotic. Excessive branching of affected roots sometimes occurs (See picture).
  2. Development: Root knot nematodes usually invade plants in the spring or early summer, within 1 or 1.5 months of germination. Each root knot contains one or more females, which produce large egg masses within their saclike bodies. By midsummer the eggs are extruded and the nematodes over-winter as eggs. Usually there is one generation per year.
  3. Hosts/Distribution: Root knot nematodes have a very wide host range, including all small grain cereals. Meloidogyne naasi appears to have specificity for cereals and grasses, and can be found wherever cereals are grown.
  4. Importance: The damage caused by root knot nematodes depends on the number of egg masses in the soil, but can be up to 90% on wheat. All cultivars of winter and spring wheat seem to be compatible hosts of the nematode. In extreme attacks, seedlings may be killed. Such factors as nutritional deficiencies, poor drainage, and soil-borne diseases can conceal the presence of nematodes.


  • Professor I. Halil Elekcioglu- Principal Nematologist, Cukurova University, Adana, Turkey.

Root Knot Nematode