Title: The C. Wayne Ellett Plant and Pest Diagnostic Clinic: a resource for dealing with plant and pests related issues.

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The C. Wayne Ellett Plant and Pest Diagnostic Clinic (PPDC) moved to The CFAES Wooster Campus about a year ago. We are located at the OSU CFAES Wooster Campus on the second floor (Selby Hall, room 234) of the Department of Plant Pathology. We continue to provide diagnostic services and support for plant and pest-related problems for a wide range of stakeholders (agricultural/green industries, growers and agribusinesses, health care professionals and the general public).



All plant and arthropod samples are evaluated by Francesca (Program Director and Plant Diagnostician) and Suranga Basnagala (Arthropod Diagnostician and Entomology Coordinator) in the PPDC laboratories located on the CFAES  Wooster campus.

Todd Hicks (Turfgrass Diagnostic Coordinator) handles turf samples at the Ohio Turfgrass Foundation Research and Educational Facility in Columbus – more information can be found at: https://ppdc.osu.edu/submit-sample/turfgrass, while nematode analyses are handled by Dr. Horacio Lopez Nicora and his team in the Soybean Pathology and Nematology laboratory in the Department of Plant Pathology, Kottman Hall, main OSU campus in Columbus. More information can be found at:  https://ppdc.osu.edu/submit-sample/nematodes



The Diagnostic Team of the C. Wayne Ellett PPDC. From left to right: Dr. Francesca Rotondo, Suranga Basnagala, Todd Hicks and Dr. Horacio Lopex-Nicora.

The Diagnostic Team of the C. Wayne Ellett PPDC. From left to right: Dr. Francesca Rotondo, Suranga Basnagala, Todd Hicks and Dr. Horacio Lopez-Nicora.



Regardless of the type of samples you would like to submit, it is important to remember that a good diagnosis starts with a good sample. For a plant sample, whenever it is possible, consider submitting the entire plant: dig down into the surrounding soil about 6 to 8 inches, wrap the roots in a plastic bag and secure it with string, put everything in a second plastic bag and secure with string and place it in a sturdy container to avoid crushing during the shipment. If it isn’t possible to submit the entire plants (we are aware that trees and shrubs are not easily movable), consider submitting the different parts of the tree/shrub. Often yellowing of the canopy and wilting are symptoms of root pathogen infection, and the pathogen is detected and isolated at the crown and root level of the plant. 


Always submit multiple twigs and branches displaying symptoms. Branches (1-2 inches in diameter) that are actively wilting are the ideal sample to test for wilting diseases (oak wilt and Verticillium wilt). The transition zone, the area between dead and healthy plant tissue, is another important concept to keep in mind when selecting the material to send for analysis. Dead material is not suitable for diagnostic analyses.


Samples can be hand delivered to Selby Hall in Wooster campus. Instruction for hand delivery of the samples can be found here.  https://ppdc.osu.edu/submit-sample



A good diagnosis starts with a good sample

 Ship the sample in sturdy boxes and, when possible, submit the entire plant.



For Insect and arthropod identification, it is important to provide more than one specimen to be sure that there is enough intact material for the analysis. An experienced diagnostician can identify parts of the insect up to the order or genus but in many cases, the antennae and all legs are needed for identification.


Before submission, most specimens can be killed by putting them in a container and placing them in the freezer overnight. This is recommended for large and fragile insects.  Alternatively, they can be killed by placing them in a glass or plastic jars containing 70 to 90-percent ethyl or isopropyl alcohol. Water is not suitable for preserving specimens. We recommend not to use alcohol when sending the caterpillars and grubs stages as the color can fade away when you store them in alcohol. If you must store them in alcohol, always take several high-resolution pictures (with a scale) before you put them in alcohol and send us the images. The color of the caterpillars is a key character in identifying them. Plant pests, such as mites, aphids, maggots, caterpillars and scale insects are very fragile, and they should be shipped with the plant material. Furthermore, the plant host is often crucial for an accurate identification of this type of pests. The samples can be put in a zip-seal plastic bag and placed in a sturdy box that will not be crushed during shipping.


Regardless of the type of samples that you are sending in, use an overnight mail service or next-day shipping to preserve the freshness and quality of the material. Choose to mail packages early in the week to avoid weekends at the post office.

Same as other samples, insect samples also can be hand delivered to Selby Hall in the Wooster campus. Instruction for hand delivery of the samples can be found here.  https://ppdc.osu.edu/submit-sample



We also accept digital sample submissions through our website (https://ppdc.osu.edu/digital-samples). Always submit a generous amount of well-focused, high-resolution pictures that cover symptoms distribution on the plants, close-ups of the symptoms (e.g. upper side and underside of the leaves, twigs, branches), and pictures of the surroundings. This will help us to understand the overall severity of the disease, how much is spread and if only specific plants are affected.



Suffering Boxwoods

Suffering boxwood shrubs and a close-up of some of the symptoms observed.



For insect digital diagnostics, include as many photos as possible of the specimen, of the​ an area where it was collected/seen, and if applicable, of the plant damage and the distribution of the symptoms.  If possible, always include a ruler or a coin for size comparison.


Digital sample for insect identification

An example of well-focused pictures submitted for insect identification. The first picture is a Green June Beetle with a reference ruler and the other is sawfly larvae showing the damaged leaves.



More information can be found on our website at ppdc.osu.edu. We are actively working on our website to improve it and share our diagnostic updates with you.