Plant Disease Diagnosis

The NDSU Plant Diagnostic Lab strives to provide timely and accurate plant disease diagnoses and research-based recommendations. Our lab analyzes plant and soil samples for pathogen/biotic and abiotic disorders. NDSU PDL also conducts phytosanitary testing in support of ND Department of Agriculture (Plant Industries Division).

For ND residents, NDSU Extension has an office in every county staffed with extension agents ready to assist in identifying plant or pest issues. Should the agents encounter challenges in diagnosing the problem or if testing services are required, they promptly forward the sample to PDL for further analysis.

Find the NDSU Extension county office closest to you

Our lab accepts samples from across the United States; however, if you reside outside of North Dakota, we recommend reaching out your local Extension office or a diagnostic lab/clinic within your state for assistance.

Please refer to the sample submission guidelines below before submitting samples.

Diagnostic Sample Submission Form

Services and Fees

$30 per plant sample

Routine diagnosis includes visual observation, microscopic examination and moist chamber incubation when needed.

$50+ for culturing per sample

Culturing may be needed to identify the fungi or bacteria from samples. Fees typically do not exceed $50 per sample.

$50 per sample

Available for:

  • Dutch elm disease
  • Verticillium wilt
  • Oak wilt (red oak only)

For oak wilt analysis (molecular testing) of white and bur oak, please contact UMN Plant Disease Clinic.

PCR-based assays ($100 minimum)

Molecular Analysis - PCR
$70 base fee - DNA extraction and PCR
$35 per additional sample

Molecular Analysis - qPCR or RT-PCR
$80 base fee - plant RNA or soil DNA extraction and PCR
$40-45 per additional sample

Available tests:

Aphanomyces root rot (A. cochlioides, A. euteiches)
Fusarium root rot (Fusarium spp., F. avenaceum, F. solani)
Pythium root rot (Pythium spp., P. ultimum)
Verticillium wilt (Verticillium spp., V. dahliae)
Phytoplasma diseases
Potato
Bacterial ring rot (Clavibacter michiganensis subsp. sepedonicus)
Black dot (Colletotrichum coccodes)
Brown spot / bacterial wilt (Ralstonia solanacearum)
Common scab (Streptomyces spp.)
Powdery scab (Spongospora subterranea)
Silver scurf (Helminthosporium solani)
Soft rot (Pectobacterium and Dickeya spp.)
Potato mop-top virus (PMTV) and Tobacco rattle virus (TRV)
Potato spindle tuber viroid (PSTVd)
Soybean
Brown stem rot (Cadophora gregata)
Sudden death syndrome (Fusarium virguliforme)
Soybean rust (Phakopsora pachyrhizi)
Phytophthora root and stem rot (Phytophthora sojae)

Please contact us for availability of PCR tests for other pathogens.

$60 first sample
$15 per additional sample/test

Available tests:

Potato
Alfalfa mosaic virus (AMV)
Potato latent virus (PotLV)
Potato leafroll virus (PLRV)
Potato virus A (PVA)
Potato virus M (PVM)
Potato virus S (PVS)
Potato virus X (PVX)
Potato virus Y (PVY)
Potato virus Y-necrotic strain (PYYn)
Potato virus Y-o+c strains (PVYo-c)
Small Grains
Barley stripe mosaic virus (BSMV)
Barley yellow dwarf virus-MAV (BYDV-MAV)
Barley yellow dwarf virus-PAV (BYDV-PAV)
Cereal yellow dwarf virus (CYDV)
High plains wheat mosaic virus (HPWMoV)
Wheat streak mosaic virus (WSMV)
Legumes
Bean pod mottle virus (BPMV)
Cowpea mosaic virus (CPMV)
Pea seed-borne mosaic virus (PSbMV)
Pea enation mosaic virus (PEMV)
Soybean mosaic virus (SMV)
Solanaceous Crops
Tomato spotted wilt virus (TSWV)

Please call us for availability of ELISA tests for pathogens not listed above.

$10 per test
$30 fee for routine diagnosis may apply

Available tests:

Fungi and Oomycetes
Rhizoctonia solani (Rs)
Phytophthora (Phyt)
Bacteria
Xanthomonas (Xan)
Viruses
Cucumber Mosaic Virus (CMV)
Hosta Virus X (HVX)
Tobacco Mosaic Virus (TMV)
Tomato Spotted Wilt Virus (TSWV)

Please contact us for availability of Immunostrip tests for pathogens not listed above.

Please contact us for availability of analyses for soybean cyst nematode (SCN) and other nematodes.

$35 SCN counts

The ND Soybean Council (NDSC) covers up to 2,000 SCN samples for ND growers. For more information about SCN sampling program, contact Wade Webster.

How to Sample for SCN

Please contact us for availability.

Sequencing

$100 base fee - PCR and sequencing
$50 additional sample

*Fees for culturing still applies.

General Sample Submission Guidelines

  • Select plants showing various stages (early and late symptoms) of the problem.
  • Choose plants or plant parts showing the area between the healthy and dead tissue.
  • Send the entire plant whenever feasible. Avoid sending completely dead plants.
  • Supplement physical samples with photos. Include close-up of the symptoms, entire plant and the surrounding area. Make sure that the images have good resolution and are in focus. Send photos to ndsu.pdl@ndsu.edu.

  • Download the diagnostic sample submission form
  • Include your contact information (address, phone and email) and the place where the sample was collected.
  • Fill out as much information as you can. Do not worry about filing out every section of the form.
  • Describe the problem in detail and provide additional information on the reverse side of the form.

  • Wrap the plant sample loosely in dry paper towel to prevent leaves from contact with moisture.
  • For samples with roots, keep some soil on the roots and wrap in a plastic bag secured with a twist tie around the base of the plant.
  • Place the sample in a zippered or sealed plastic bag. Do not add water or wet paper towels to the bag.
  • Use a sturdy box to mail your sample. Avoid using flat envelopes to prevent shipping damages.
  • Put the submission form on its own plastic bag. Please do not put the form in the bag with the sample.

  • Drop off or mail the sample as quickly as possible to the appropriate address found here.
  • We recommend shipping your sample early in the week so we can receive it by Friday.
  • If the sample cannot be sent immediately, keep it refrigerated. Avoid letting the sample sit in the packaging and under direct sunlight.
  • If submitting both physical and digital samples, send photos to ndsu.pdl@ndsu.edu. Please include your contact information and shipping date of the physical sample.

  • We will email the report once diagnosis is complete.
    • Report will be sent to the extension agent if the latter submitted the sample for the client.
    • If fees apply, the invoice will be sent along with the report.
  • Most samples are completed within a few days. Other samples that requires culturing or testing can take several weeks.