Submitting a Plant Sample


Plant samples for diagnosis or identification can be mailed to or dropped off at the clinic directly (see address below). Samples can also be taken your local extension office.

Office Address and Directions

Plant and Insect Diagnostic Clinic
327 Bessey Hall
Iowa State University
Ames, IA 50011

Directions to the clinic from I-35, as well as a map of our location on Iowa State University's campus, can be found here.

Submission Forms

Please print and complete the appropriate submission form and include it with your sample.

General Tips for Sample Submission (including packaging and mailing)

General Tips When Scouting and Sampling Crops

While in the field take pictures of the symptoms (close-up and general distribution in the field). Quality pictures are needed, use the macro option in your camera (tulip icon in most cameras and smart phone cameras) for close-ups. Attach the picture into an email to and in the subject include submitter last name, crop and sample submission date (MM/DD/YY). Example: Smith-pepper-5/20/15.

Collect several samples. Select plants from areas where symptoms are starting, developing and developed. Avoid plants with advanced symptoms. A completely wilted or dead plant is not a good subject to submit. When submitting a plant, roots and all, make sure the soil is contained so it does not make contact with the foliage.

Plant Submission Instructions

Field Crops

Send several whole plants, roots and all.

It is best if you dig the whole plant out of the ground, to ensure that you send us as much root tissue as possible (specially in Seedlings)It is also important to remember that sometimes above ground symptoms are being caused by diseased roots.

Other details to include are cropping history, the pattern of symptoms in the field, chemical history, and cropping history.


Collect samples with symptoms representative of what you are seeing in the field. Wrap specimens (twigs with leaves, branches and/or fruit) in enough clean, absorbent material (such as paper towels) to absorb all leaks, do not add moisture. Please note in your submission form if you see cankers (sores in twigs, branches or trunk) or a gummy material oozing from them.

Vegetable and annual ornamental crops

Seedlings: send whole plug trays, leave the plugs in the tray.

Whole plants: Collect three to 5, depending on size.  If potted, bag the pot and seal at the soil line with a twist tie or a rubber band bag. . Use another bag for the aerial plant parts, but do not cut the root ball off the above-ground plant parts. Use another bag for the aerial plant parts, but do not cut the root ball off the above-ground plant parts.

In the field, dig around the roots instead of pulling the plants. Shake most of the soil off the roots. Bag the roots and seal at the soil line with a twist tie or a rubber band. Use another bag for the aerial plant parts, but do not cut the root ball off the above-ground plant parts.

Herbaceous Plants

When possible, include the entire plant, with the root system and surrounding soil. Often what appears to be a leaf problem is really a root related problem.

Enclose the root ball in a plastic bag to keep the soil from touching the leaves. Include enough plant material to show all stages of the disease.

When possible, provide several whole plants.


Before applying any disease-controlling chemicals, collect turf grass from the edge of the affected area. The sample should include both healthy and infected plants. Completely dead grass is of no use since secondary organisms quickly colonize it.

Take a sample of at least 6" diameter (a cup cutter works well). Include the underlying soil and root system.

Wrap the sample in newspaper or paper towels. Please do not place it in a plastic bag and do not add water. Excess moisture can cause rapid deterioration of the sample and proliferation of secondary organisms.

Provide background information, such as when the symptom first appeared, turf grass variety, and pattern and distribution of the problem. Pictures of symptoms can be very helpful.

Pack your wrapped sample tightly in a box to prevent dislodging the soil. Ship the package early in the week via overnight delivery.


When possible, include the entire plant, with the root system.

Please include information about where you found the plant (county in Iowa), what sort of conditions it was growing in, and how many of the plants you observed in the area. 

Weeds should be wrapped in dry paper toweling or newspaper.

Woody Plants

Collect samples from branches that are showing symptoms but are not dead.

For Dutch elm disease, oak wilt*, and Verticillium wilt testing, branch specimens should consist of four to six pieces, measuring 6 to 8 inches long, and 1/2 to 1 inch think.

*For suspected oak wilt samples,  follow the instructions on the oak wilt sampling checklist.  Send the samples overnight and include ice in the packet. If the sample cannot be sent right away, it needs to be refrigerated.

 When submitting cankers, include the portion of the branch at the border between discolored and healthy bark.