How to Prepare Your Sample
General Submission Guidelines
- Submit samples that show both healthy and symptomatic tissue
- Wait to collect the samples until right before you send them or keep samples cool until ready to be sent
- Send samples early in the week (Mon‐Wed), preferably via one‐ or two‐day delivery
- Include a Plant Clinic sample submission form with the sample (available on our website)
- Do not seal packages in plastic bags with wet paper towels
- Packages from outside Illinois should be double-bagged and have all seams sealed with packing tape
- Do not send payment with sample; you will be invoiced.
Note: 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.
Preparing Plant Specimens for Disease / Injury Diagnosis
Read more on How to Submit a Sample.
- Leaf Tissue: Collect both healthy and symptomatic leaves. Leaves can be stored in a paper bag or open plastic bag. Do not place leaves in a sealed plastic bag.
- Branch Samples with Leaves or Needles: Send branches showing healthy and symptomatic leaves, needles and cones, if possible. Do not remove leaves, needles, or bark before shipping.
- Woody Vascular Disease: For suspect Oak Wilt, Dutch Elm Disease, Verticillium Wilt, etc.: Select branches that are actively wilting but not totally dead. Branch samples should ideally be 8‐10 inches long, approximately 1‐2 inches in diameter. Wrap the branch in foil or a plastic bag. Keep the sample cool, and ship overnight with a cold pack.
- Fruits and Vegetables: Send whole fruits or vegetables when possible. Samples should not be placed in an air‐tight bag.
Please ship these samples in a crush‐proof container.
- Root Samples: Dig the roots out of the ground and send both roots and soil in a plastic bag.
- Turf Samples: Use a sharp knife or trowel to cut a 3” diameter core at least 2” deep. The core should contain both healthy and affected grass, and should include leaves, roots and soil.
- Whole Plants: Dig the roots out of the ground and place the plant in an unsealed plastic bag. Wrap the roots in plastic or newspaper to keep them from drying out. Send the soil with the roots, and ship in a crush‐proof container. Newspaper can be used to cushion plants in the package.
- Soil Nematode Samples: Submit soil samples in sealed wax paper or plastic bags. Make sure each bag is numbered or marked. See our website for more information about taking soil samples.
- Insect Samples: Insects should be packaged in crush‐proof containers, either in rubbing alcohol or cushioned with small pieces of crumpled up paper. Do not tape insects.
Preparing Nematode Specimens
Read more on How to Take a Nematode Sample and Guidelines for Submitting a Nematode Sample.
How much soil should be submitted for each test?
- For all tests: fill a gallon bag ziptop bag at least halfway with soil taken from approximately 6 inches below the soil line.
- Double bag when possible to reduce the risk of bags opening in transit.
Do roots need to be included?
- For soybean cyst nematode sampling: roots are not needed. They may be included as part of a specialty nematode analysis. Please contact us before submitting this type of sample.
- For corn vermiform nematode sampling: soil samples should be taken from the root zone, collecting roots with the soil.
When should samples be taken?
- SCN egg count samples are ideally collected in the fall after soybean harvest, however, fields can be sampled any time the soil isn’t completely saturated with water or frozen.
- Corn vermiform samples are ideally taken in spring when plants are approximately 4‐6 weeks old. Fall sampling for corn vermiform identification and enumeration isn’t recommended for predicting the next year, but it can provide information about the current year.
How should samples be stored?
- Samples should be stored in a refrigerator (40F) before shipping. SCN egg count, SCN type testing, and Hg type testing samples can be stored for up to a month before shipping. Vermiform samples should be shipped within a week of collection and should be handled gently.
- Soil samples for all tests need to be kept cool in the field and should not be left in direct sunlight or in a hot vehicle.
How should they be shipped?
- Samples for all tests need to be kept cool during shipping. Shipping overnight with an ice pack, or dropping off samples in person is recommended. Samples need to be kept cool during transit if the client is dropping them off.
Complete and include the Nematode Soil Sample Form with the sample.
Preparing Insect Specimens
Insects should be packaged in crush‐proof containers, either in rubbing alcohol or cushioned with small pieces of crumpled-up paper. Do not tape insects.
For additional information on how to collect and submit a sample for diagnosis contact your local University Extension Office, or call the Plant Clinic at (217) 333-0519.
Plant Clinic Address
S-417 Turner Hall
1102 S. Goodwin Ave.
Urbana, IL 61801