Plant Pathology Diagnostic Laboratory Services

Directions for submitting samples

The Plant Pathology Laboratory at the Hermiston Agricultural Research and Extension Center is equipped to identify a number of plant disease problems. It is important that plant samples are properly submitted to the lab to ensure proper and timely identification. Please follow the instructions below when submitting a sample.

Note: Failure to recover or confirm an organism from a sample does not establish the field to be free of that organism.

1. Collect samples

• Send or bring in as much of the plant as possible. Many diseases are the result of damage to or infections in parts of the plant that are distant from the parts of the plant that show symptoms. If possible, bring in roots, stems, leaves, flowers, and even the soil around roots.
• Submitting healthy plant samples is useful for comparisons.
• To make an accurate and timely disease diagnosis, it is important that plant disease samples being sent to the lab arrive in the best condition possible.
  • Put plants in a paper bag and put paper bag in a box for shipping. Pack brittle samples in dry packing material (paper towels) so they aren’t crushed during shipment.
  • Do not put samples in wet paper towels or in a sealed plastic bags, this will cause the plant tissue to rot and will make diagnosing the problem difficult or impossible. If you are concerned that the sample will dry out before it gets to the lab, wrap cut ends in a dry paper towel and place wrapped ends in a plastic bag. Secure plastic bag to stems with rubber bands. Keep samples cool until shipping and mail samples early in the week.
• If sending soil samples for fungi testing:
  • Take 4-10 small samples from different parts of the area of concern and combine them in a sealable plastic bag or soil sample bag of appropriate size. Usually one quart of soil is enough to run all soil fungi tests.
  • For large areas such as agriculture fields, it might be useful to submit more than one soil sample per field. For example, one sample from the north, south, east, and west quadrants of the field. If submitting soil from a diseased area, take another soil sample from an area where plants are healthy.
  • Put sample bags in a sturdy box and be sure to secure sample bag opening so it doesn’t open during shipment.
• If preparing potato tuber samples and for bacterial ring rot testing:
  • Randomly select the required number of tubers (usually 4,600) best collected randomly at harvest but can come from across the top of the entire pile and place them in groups of 200 in a plastic container lined with a new garbage bag. For example, a sample of 4,600 tubers would require 23 subsamples of 200 tubers. Be aware that tuber samples that are less than 4600 will not generally be adequate to test a seed lot for BRR
  • Tuber core samples are then taken from each of the subsamples using a 13mm melon baller.
    • Wash the melon baller first with soap and water and then disinfect the melon baller by dipping the METAL portion of the tool in 95-100% alcohol and pass through a flame. Allow the alcohol to completely burn off before using. If this is not an option, disinfect the tool with a standard commercial disinfectant, replacing the disinfectant as needed. Repeat this process between each seed lot but not between each subsample of each seed lot.
    • When the tool is ready to use, take a sample from each tuber at the stolon (stem) end containing as much of the vascular ring as possible. Melon ballers should NOT be larger than 13mm, but can be as small as 10 mm.
  • Place the cores from the 200 tuber sub sample in a 1 quart plastic Ziploc bag and seal. Make sure each bag is labeled with seed lot information and sub sample number.
  • The garbage bag can now be removed, closed, and labeled. It is recommended that tuber samples are kept until all testing is complete. Core samples should be stored in the refrigerator at 4ºC (39ºF) and brought to the laboratory as soon as possible. Again schedule submission with the plant pathology laboratory. Cores should NOT be stored for more than a few days before submission.

2. Complete a Plant Pathology Sample Submission Form

Download the Plant Pathology Sample Submission (PPSS) Form

Download the Plant Pathology Soil Submission Form

Proper and timely diagnoses also require as much background information about the disease sample as possible. Fill in as much of the PPSS Form as possible. Sample processing may be delayed if a sample submission form is not included with shipped samples.

3. Send samples to the Plant Pathology Lab

• Plant or soil samples can be submitted to the lab by either bringing the sample directly to the HAREC Plant Pathology Lab or the HAREC Main office or by mailing samples via USPS, FedEx, or UPS to the following address:
  • Extension Plant Pathology Laboratory
    Oregon State University
    Hermiston Agricultural Research & Extension Center
    2121 S. 1st Street
    Hermiston, OR 97838
• Digital pictures of the plant symptoms in the field are also useful and can be sent into the lab or E-mailed to Ken Frost at: [email protected].
• Reports can be E-mailed as a PDF, faxed, or sent as a hard copy along with the invoice for testing fees. Reports can also be relayed via telephone upon request.