Plant and pest diagnostic clinic | Agriculture

Aaaaaaaack! What’s killing my plants? This question is all too common to many Extension educators and asked daily in plant diagnostic clinics across the country. Don’t guess, test! The Plant & Pest Diagnostic Clinic (P&PDC) at the University of Nebraska-Lincoln is available to help answer this question and provide scientifically sound management recommendations.

As the weather warms and the growing season begins, we hope that all plants will be happy and healthy. Unfortunately, we know that there is an abundance of diseases, pests and adverse environmental conditions that prevent crops from reaching their maximum production potential. While there are many resources available to aid in diagnostics, different problems often produce similar symptoms. Are plants yellow and stunted due to a nutrient deficiency or a nematode problem? Is that skip in the row due to insect feeding or a fungal root rot? Control for each problem varies widely, and correctly identifying the cause is the first step toward finding a solution.

The goal of the P&PDC is to quickly and accurately identify weeds, insects and diseases on any plant. In addition to common row crops such as corn and soybeans, the P&PDC provides diagnostic support for landscape, horticultural and any other plants that may be a part of your life. Unfortunately, we are not set up to conduct tissue testing for nutrient deficiencies/toxicity or chemical injury. These samples are diagnosed purely based on visual observations of symptoms.

How samples are submitted to the P&PDC plays a large role in not only the ease of diagnosis, but also how quickly samples can be turned around. There are several important things to consider when submitting a plant or insect sample to a plant diagnostic laboratory. The fastest diagnoses result from high-quality samples and as much background information and field history as possible.

Collecting an adequate amount of plant material is critical; if feasible, collect the entire plant — roots, stems, leaves, flowers and fruits. This is important because problems in the upper part of the plant are often caused by problems with the roots or crown. Unlike testing tissue for nutrition, we want all samples placed in a sealed, plastic bag with a clean paper towel to ensure freshness. Once a sample is dried or degraded, an accurate diagnosis becomes much more difficult. Samples should be placed in the mail Monday through Wednesday to reduce the likelihood of them spending the weekend in a mail truck before they arrive at the P&PDC. If dropping samples off, the clinic is open 8 am to 5 pm Monday through Friday, and we welcome walk-ins. The P&PDC’s physical address is 448 Plant Science Hall, 1875 N. 38th St., Lincoln, NE, 68583

While it is not always feasible to collect the entire plant, photos of symptomatic plants can greatly improve the accuracy of diagnostics. While identification of plant diseases and insects may not be 100% accurate from a photo, this can be a great way to start identifying the cause of plant decline and if a physical sample is required

For more information, contact your local Extension office, visit the P&PDC’s website (, call 402-472-2559, or email


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