Root-knot nematodes - Meloidogyne spp.
Effective: April 11, 2011 - December 31, 2013
Taxonomic Position: Tylenchida : Heteroderidae
Pest Type: Nematodes
Pest Code (NAPIS): NEOBCAA
These Approved Methods are appropriate for: 2013, 2012
Pest Information
CAPS Pest Datasheet: https://download.ceris.purdue.edu/file/
Pest Tracker: https://pesttracker.org/pest/NEOBCAA
Pest is vectored by:
This pest is is not known to be a vector and it is not vectored by any organism.
Survey

Approved Method(s)
Method Detail NAPIS Survey Method
Soil Sample Send sample to nematology diagnostic lab where nematodes will be extracted and identified. 3012 - General Soil Sample
Tissue Sample Collect abnormally swollen roots and send to a nematology diagnostic lab where damage and galled roots will be assessed. 3011 - General Tissue Sample

Survey Recommendations
The following are recommendations for executing the survey using the approved methods for pest surveillance. The recommendations are developed through literature review and consultation with subject matter experts.
Signs:
Nematode egg masses are often visible on the surface of galls.
Symptoms:
Root-knot nematodes (RKNs) symptoms are similar to those caused by nutrient or water deficiency, including stunting, wilting, and chlorosis of leaves. Small root galls and lateral proliferation of roots is also observed with most species. For citrus RKNs, yellowing of leaves, premature flower drop, early ripening and fruit drop, and reduced fruit quality and yield are observed. Citrus roots infected by root-knot nematodes show swollen rot tips and axes.
Key Diagnostic or Identification

Approved Method(s)
ID/Diagnostic:
Assessment of root galls will indicate a possible root knot nematode infection.

Morphological: The length of at least 20 second-stage juveniles, the head and stylet morphology of males, and the nature perineal patterns of females from samples.
Mistaken Identities:
Other Meloidogyne species (M. arenaria, M. hapla, M. incognita, and M. javanica)
Notes:
The occurrence of RKNs on weeds is common in citrus groves. Soil samples from these groves are often positive for root-knot nematode because they originate from weed hosts. Careful examination and separation of roots in the samples provides certainty of the origin of nematode infestation.
References
  1. Davis, E.E. and Venette, R.C. 2004. Mini Risk Assessment - Asian Citrus Root-knot Nematodes: Meloidogyne citri; M. donghaiensis; M. fujianensis; M. indica; M. jianyangensis; M. kongi; and M. mingnanica. Cooperative Agricultural Pest Survey, Animal and Plant Health Inspection Service, US Department of Agriculture.
  2. Hunt, D. J., and Handoo, Z. A. 2009. Taxonomy, Identification and Principal species. In: Root-knot nematodes. Perry, R. N., Moens, M., and Starr, J. R. (ed.) CABI Publishing, UK. pp. 55-97.
  3. Perry, R. N., Moens, M., and Starr, J. R. (ed.). 2009. Root-knot nematodes. CABI Publishing, UK, 488 pp.

If you are unable to find a reference, contact STCAPS@usda.gov. See the CAPS Pest Datasheet for all references.