Submitting a Plant Sample

Table of Contents

Plant samples for diagnosis or identification can be taken to your local extension office or mailed to or dropped off at the clinic directly.

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

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

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

For plant problem samples ($20 fee) – disease, insect, herbicide, please use form PD 31 "Plant Problem Diagnosis".
For plant, weed, and mushroom samples needing identified ($10 fee), please use form SP 258 "Plant and Weed Identification".
For soybean cyst nematode and corn nematode sample submission, please use form PD 32 "Plant Nematode Sample Submission".

Provide plenty of plant material. When possible send the entire plant, including roots and top growth.
Provide lots of information, such as a description of the soil, nearby plants, and a history of the problem.
Include photos when possible. We welcome videos and will return them to you.
Provide freshly collected specimens.
Be sure the specimen represents the problem.
Include enough plant material to show all stages of the disease from healthy to very sick.
Wrap specimens in paper towels or clean newspapers. Do not add moisture. Pack loosely in a plastic bag to reduce drying. Mail in a sturdy container.

Send several whole plants, roots and all.
Include a cropping history and the pattern of symptoms in the field. Some diseases tend to be distributed in a characteristic pattern.

Wrap specimens in enough clean, absorbent material (such as paper towels) to absorb all leaks.

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 turfgrass 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 symptom first appeared, turfgrass 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.

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

Iowa State University Plant and Insect Diagnostic Clinic