UD Plant Diagnostic Clinic

A collage of various plants both with and without disease.

Due to the current COVID-19 situation, University of Delaware offices are closed to protect the health and safety of our community. During this period we want to remain as responsive to clientele as possible. Agents are still responding to phone calls and distance communication.


Plant testing
Please take a moment to read the updated protocols for submitting samples during COVID-19, then download and complete the Plant Diagnostic Submission form.

Insect testing
If you have insect diagnostic samples please contact the agent covering agriculture or horticulture for your county

Soil testing
Soil test submission procedures have changed. For up to date soil testing information, including how to purchase kits and submit soil samples please visit the Soil Testing Laboratory’s website.

The Plant Diagnostic Clinic at the University of Delaware accepts plant samples showing signs or symptoms of disease.

The clinic is housed in the Department of Plant and Soil Sciences at the University of Delaware in Newark, operating as a function of Delaware Cooperative Extension. Plant pathology is the study of plant disease and the control of plant diseases.

The UD Plant Diagnostic Clinic is a part of the National Plant Diagnostic Network (NPDN). The mission of the network is to enhance national agricultural security by quickly detecting introduced pests and pathogens. This system links diagnostic laboratories with common strategies and tools, and increases communication among plant pathologists and the public.

How to submit a sample

Please take a moment to read the updated protocols for submitting samples during COVID-19

The Delaware Plant Diagnostic Submission Form must accompany any sample, with information filled in as completely as possible. Many homeowner samples may not need to be sent to the Clinic, but may be diagnosed by Master Gardeners or County Agents in the county Extension offices. A fee-based system for cost recovery is being developed, to be implemented in January of 2017. As of August 2016, a $20 charge covers bacterial leaf scorch (BLS) testing. For BLS testing, at least 25 leaves are required and the test may take up to two weeks to run.

Here are some helpful hints and suggestions to help all of us to accurately and quickly diagnose plant disease and insect samples that come in.

  1. If a sample consists of just one or two leaves of an unknown plant or a dead brown branch, we probably will not be able to tell much.  Please request a new sample from the client.
  2. Samples should be placed in a ziplock plastic bag. Samples in open plastic bags from grocery stores or paper are usually too dry by the time they get to Newark.
  3. Wet, soft fruits or vegetables should be placed in dry paper towels and then double bagged in case they break down and leak.
  4. Turfgrass samples should contain a margin between healthy and diseased, and should be a section of turf with a bit of soil underneath (4x4 inches is good). Plastic containers such as butter tubs or for left-overs work well as containers.
  5. Anything sprayed with a pesticide should not be sampled and sent for at least 24 hours.
  6. Insect identifications can be made from plants, household, or foundation habitats. Anything from a human body is not appropriate to send to Newark, and should be sent to the Department of Health.
  7. Information filled in on the forms can be very helpful. Remember, this work is like doing a jigsaw puzzle. The more pieces we have, the easier it is to complete!

Submit a sample

Contact Us

Ph. 302-831-1390
Fax 302-831-0605

Email: jillp@udel.edu

Plant Diagnostic Clinic
531 S College Ave
151 Townsend Hall
Newark, DE 19716

Additional Resources

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