Tylenchulus semipenetrans 
The Citrus nematode
  • Damage to Citrus.  Damage caused by a citrus nematode infestation depends on the age and vigor of the

  •  tree, density of the nematode population, and susceptibility of the rootstock
  • Biology.  The citrus nematode is an obligate parasite, reproducing only on living roots of host plants. The young adult females  penetrate the root, producing a gelatinous matrix in which the eggs are embedded. These hatch and the second-stage juveniles attack roots.
  • Ecology.  Tylenchulus semipenetrans occurs worldwide on citrus. 
  • Symptoms.  Above-ground symptoms associated with nematode-infected trees are wiIting, lack of vigor, poor fruit production and poor response to watering and fertilization. Another common symptom of infection by high populations of this nematode is the encrusted appearance of the

  • roots due to the soil particles that adhere to the female's jellylike egg matrix .
  • Damage to other crops.  It also parasitizes grape, lilac, olive, and persimmon. 
  • Control.  Chemical control of nematodes on established trees is expensive and must be repeated annually for best results. Prevention by exclusion is best.
  • Links and References.  Citrus nematodes.  University of California     Tylenchulus semipenetrans