| COMMON NAME | SCIENTIFIC NAME |
| ROOT KNOT | MELOIDOGYNE INCOGNITA (I) |
| MELOIDOGYNE ARENARIA (A) | |
| MELOIDOGYNE JAVANICA (J) | |
| MELOIDOGYNE HAPLA (H) | |
| SUGARBEET CYST | HETERODERA SCHACHTII |
| LESION | PRATYLENCHUS THORNEI (T) |
| PRATYLENCHUS NEGLECTUS (N) | |
| STEM & BULB | DITYLENCHUS DIPSACI |
| (SEVERAL BIOTYPES) |
Listed above are nematodes found in samples taken from fields in Yolo County.
The most common root-knot species is M. incognita which is recovered about 80 % of the time that root-knot nematode is present. It is important to do a species identification for root-knot nematode because nematode resistant tomatoes are an option and they are not resistant to M. hapla.
It is not uncommon for a single field to have several nematode genera present.
Research by Viglierchio has shown several biotypes of D. dipsaci to be present in California which can only be distinguished by host range testing.