Mexican corn cyst nematode - Punctodera chalcoensis
Effective: August 18, 2010 - December 31, 2017
Taxonomic Position: Tylenchida : Heteroderidae
Pest Type: Nematodes
Pest Code (NAPIS): NEFBDBB
This pest is a member of the following surveys: Corn, Cyst Nematode
These Approved Methods are appropriate for: 2018, 2017, 2016, 2015, 2014, 2013, 2012, 2011
Survey
Approved Method(s)
Method |
Detail |
NAPIS Survey Method |
Soil Sample |
Send sample to nematology diagnostic lab where nematodes will be extracted and identified (preferred method). |
3012 - General Soil Sample |
Tissue Sample |
Send sample to nematology diagnostic lab where nematodes will be extracted and identified. |
3011 - General Tissue Sample |
Method Notes: Laboratory methods that are acceptable for cyst extraction include sugar centrifugation, USDA cyst extractor, Fenwick can sieving, wet sieving, and elutriation.
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: Mature females and cysts are just visible to the naked eye and can be seen as minute white globes on the root surface.
Symptoms: Seedlings exhibit yellowing, stunting, and possibly even plant death. Heavily attacked plants have stunted root systems with many short laterals, giving a bottle brush effect and the aerial parts of the plants appear unthrifty.
Key Diagnostic or Identification
Approved Method(s)
ID/Diagnostic: Morphological: Characteristics of second-stage juveniles, females, and cysts.
Stone et al. (1976) provides a key to Punctodera spp.
Mistaken Identities: Punctodera chalcoensis can be confused morphologically with P. punctata and P. metadorensis.
In Progress / Literature-based Diagnostics: Molecular: Sabo et al. (2002), sequenced the internal transcribed spacer (ITS) 1, 5.8S ribosomal RNA gene, and ITS2 of P. chalcoensis, which may provide for molecular identification.
Gibson et al. (2011) sequenced the partial mitochondrial genome sequence of P. chalcoensis, opening the possibility of future diagnostic methods based on this sequence.