Issue 1, April 22, 2013

Plant Clinic Sample Submission: The Importance of a Sample Quality and Detailed Information

The first step towards correcting any plant problem is the accurate identification of the cause. A plant problem could potentially be caused by a variety of unfavorable growing conditions, cultural practices, insect pests, and plant pathogens. Some of these problems may be easily diagnosed or identified on site. Others may require the assistance of an expert or specialized equipment and methods only available in a Plant Diagnostic Laboratory.

The University of Illinois Plant Clinic is a diagnostic laboratory located on the University's Urbana-Champaign campus. The clinic's lab is set-up to handle a wide variety of plant problems and is available to help with plant and insect identification, diagnosis of disease, insect, weed and chemical injury (chemical injury on field crops only), nematode assays, and help with nutrient related problems, as well as recommendations involving these diagnoses. The majority of the samples are diagnosed by clinic staff; however, professors and other specialists from campus are often consulted for assistance.

Even with all the tools and expertise available within the plant clinic, the most limiting factors to an accurate diagnosis is sample quality and lack of information. Diagnoses and recommended controls by the University of Illinois Plant Clinic are based solely on the material and information submitted. The less representative the sample, and the less complete the information provided, the greater the chance for misdiagnosis.

If you plan to submit a sample to the plant clinic, start by reviewing the "How to Submit a Sample" section of the Plant Clinic's web page. The page has the current recommendations on how to collect, preserve, package and send a representative sample. In general, the plant clinic will need a generous amount of fresh material. For instance, when testing for oak wilt and other suspected vascular pathogens; the clinic requests several 8-10" long branches with ¾ - 1" diameters. The sample should also be collected from a live branch displaying early symptoms of disease. Samples that don't fit this description often have inconclusive results and will require resampling.

A completed Plant Clinic Specimen Data Form should be included with every sample. Take time to fill out the form and provided as much information as possible. Even the most seemingly insignificant detail may be vital for an accurate diagnosis. The specimen data form can be downloaded from the Plant Clinic's web page.

Pictures can also be quite helpful, provided they are of high quality. Pictures are used evaluate symptom patterns and site surroundings. In some instances, we may even ask for a picture of the base of a tree to check for improper planting or pictures of various affected plant parts. Avoid sending photos that are blurry and out-of-focus or those that appear as silhouettes. The former may only result in the diagnosticians feeling dizzy.

When in doubt, contact the plant clinic regarding sample submissions (217-333-0519). They will be glad to help ensure a quality sample is received. (Travis Cleveland)

Travis Cleveland

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