Submission Procedures for Plant Diagnostic Clinic Samples

Extension Plant Diagnostician;

The Plant Diagnostic Clinic is open and receiving samples, with modified protocols at this time. All plant diagnostic samples must be first submitted digitally by image, sent to county Extension offices, see instructions below.

How to Submit Digital Images (modified from VT’s Plant Clinic protocol)

  •  All digital images of plant problems for disease diagnosis should be submitted through the local county Extension agent or other designated Extension office personnel. Find the local contact info here:
  • Submit three to four well-focused, quality images that show the pattern of the problem in the location, the overall symptoms on the whole plant, and a close-up image of the symptoms.
  • If a root problem is suspected, dig up and rinse off some roots to photograph.
  • The client or Extension agent must fill out the diagnostic form ( as completely as possible. We have a fillable PDF available that can be saved and emailed.
  • Diagnostic reports will be routed to the submitting Extension agent.

For Commercial Samples (growers, arborists, etc.)
If we are unable to diagnose by image, these are the options at this time for in-person diagnostics:

  1. Mail: Samples may be sent by mail to the address below, which is checked daily during weekdays. Contact if a sample is mailed.
    UD Plant Diagnostics Lab
    PO Box 9089
    Newark, DE 19714
  2. Drop-off: There is a blue cooler chained behind a pillar in the front of Townsend Hall where samples can be left, location shown with an “x” in the image below. Contact if a sample is dropped off.
    Townsend Hall, 531 S College Ave, Newark, DE 19716
    cooler location at Townsend Hall
  1. On-site visits to commercial production operations are an option if necessary.
  2. Virtual consultation through zoom is available if you want to set up a video diagnostic call.

Non-commercial Production Samples (home gardens, etc.):
Non-commercial samples will unfortunately only be accepted digitally at this time.

Guide for Sample Collection and Shipping/Drop-Off

Collecting the Sample

  • Collect a fresh sample on the day you are going to ship or drop off. If that isn’t possible, refrigerate the sample until shipment.
  • Whole plant samples are ideal, especially with a vegetable or field crop where a whole plant can be collected; roots and soil included, especially if a root/soil problem is suspected (wilting leaves or stem discoloration/lesions).
  • If the plant is too large and root-rot is suspected, collect a trowel-full of roots from a good section (if possible) and a bad section.
  • Collect a specimen that has diseased AND healthy tissue. Collect a sample that is in the process of declining.
  • Do not send a completely dead plant. If we receive a completely dead plant, there are too many secondary organisms that make it difficult to accurately diagnose the problem.
  • If leafspot diseases are suspected, a branch or stem samples is adequate, the whole plant is not necessary. If sending leaves, keep them on the branch/stem, otherwise they can dry out.

Packaging the Sample

  • When sending a whole plant: place the root ball in a plastic bag leaving some soil attached, and tie it so the soil doesn’t contaminate the foliage. We understand this isn’t possible for very large samples, and in that case, only include roots/soil if a root problem is suspected; dig up a portion of roots using a trowel.
  • Place the plant in a Ziploc or plastic bag. Do NOT add wet paper towels to the bag, which could cause the sample to rot in shipment. Holes do not need to be poked in the bag.
  • If the sample is delicate (most fruit samples), pack the shipment with newspaper or dry paper towels so it doesn’t get smashed.

diagnostic sample packaging

Sending the Sample

  • Send to:
    UD Plant Diagnostics Lab
    PO Box 9089
    Newark, DE 19714
  • Notify when the sample was shipped.
  • If the sample cannot be shipped or dropped off on the day of collection, keep it refrigerated until shipping.
  • Mail will be checked daily during weekdays.
  • If possible, overnight the sample or ship early in the week. If at all possible, do not ship samples on a Friday. They will sit over the weekend and that greatly increases the chance of decaying.