A fresh, representative sample is critical for diagnosis. Follow these general guidelines:

• Collect whole plant samples when possible, including roots.
• Always dig plants to keep root systems intact and soil in place around the roots. Small roots are often needed for diagnosis and they may be left behind if plants are pulled rather than dug.
• If only part of a plant is collected, such as detached leaves or branches, describe the symptoms and location of affected parts clearly (e.g., young vs. older leaves, one side of plant, etc.).
• Choose several plants showing a range of symptoms, especially those in the early stages of the problem. Diagnosis may not be possible if plants are completely dead.
• Include pictures of the problem area whenever possible.
• Do not expose samples to extreme heat or cold (such as leaving them inside a vehicle) and collect samples early in the week to avoid holding them over the weekend.

Once samples have been collected properly, deliver them to our office as soon after collection as possible. Growers should not mail samples directly to the Plant Disease Diagnostic Laboratory. Be prepared to complete a Plant Disease Identification Form with the information gathered from the site. In some cases, one of our Extension Agents can diagnose the problem on site. If necessary, we will ship samples to the Plant Disease Diagnostic Laboratory.

Information about the plant, planting site, and symptoms can be as important as the physical plant material collected. Key questions to ask include:

• What kind of plant is it? Indicate the variety, cultivar, or whether the plant is a hybrid. If plant’s identity is unknown, sending a healthy plant (or picture of a healthy plant) for comparison may be helpful.
• What is the age of the plant or the planting date? Be as specific as possible with annual crops. A general time frame (e.g., month and year) is often sufficient for trees and shrubs, but do indicate whether the plant has been recently transplanted or is well-established.
• What has been done to care for the crop/plant? Include information on tillage, irrigation, fertilizer and pesticides, mulches, and other cultural practices.
• What is the weather history (e.g., drought, flood, hail, lightning, frost)? Also note any site disturbances, such as nearby construction, utility work, etc.
• What are the symptoms? Describe the problem. Take time to examine the entire plant and determine the specific location of symptoms on the plant. Note anything unusual that may not be visible on the physical sample. For example, check tree trunks for wounds or for mechanical injuries. Are there any mushrooms or other fungal fruiting bodies associated with tree trunk or surface roots?
• When did symptoms first appear? Did they appear suddenly or progress (worsen) gradually?
• Where are the affected plants? Indicate the type of production system (e.g., field, greenhouse, landscape, etc.). Also note the terrain involved, such as whether the problem is in a low wet area, on a dry slope, etc.
• How much of the crop/plant is affected? Is a single plant showing symptoms, or are scattered plants, group(s) of plants or the entire planting affected? Are plants of different types showing the same symptoms? Look for any patterns.

Plant Disease Identification Form

Tree and Shrub Disease Identification Form

Greenhouse & High Tunnel Supplemental Diagnostic Form

The soilless media test is intended for use with growth media appropriate for greenhouse or nursery crop production in containers or raised benches with limited volume. This test is not appropriate for field soil. Field soil is typically not included in growth media for these systems, nor is it recommended. If you wish to test field soil, with or without organic amendments, request a routine soil test at our office.

Parameters measured in the soilless media test include pH, soluble salts (electrical conductivity), water-soluble nitrate-N, phosphorus, potassium, calcium, magnesium, sodium, boron, iron, manganese, copper, and zinc using a saturated media extract procedure. Samples may be taken from a current crop or from bulk media before use.

Growth media samples should be representative of the bed or bench of a given crop. A sampling strategy should consider crop species, planting time, container size, and environmental parameters such as shading, location in a greenhouse or nursery bed, etc. Ideally, a sample should be taken from plants representing each of the possible variations in these factors. However, circumstances may not allow crop management to differ with each of these variations. Therefore, it is best to select several subsamples from plants that will be managed as a block and submit a
composite sample. Samples may be taken from bulk media before the crop is planted to determine beginning status.

Collect 6 to 8 subsamples from several locations in beds or from 6 to 8 representative containers in a block. Each of these subsamples should include the growth medium from the whole root zone from the surface to the bottom of the raised bed or container. This is necessary because the soluble salts and other parameters can differ with depth in a container or bed. Thoroughly mix the subsamples together to create a pooled sample and take two pints of the mixture as your sample. Two pints will fill two sample bags obtained from our office. Mark the sample with an owner ID of your choosing.

Sampling time should also be considered relative to recent management activities or environmental events such as rainfall. If a crop is receiving routine liquid fertilization, it is generally accepted to wait four to six hours after the application before sampling.

Soilless Media Test for Greenhouse and Container Nursery Production

Each sample will be analyzed for: pH, conductivity, alkalinity, nitrate-N, phosphorus,
potassium, calcium, magnesium, zinc, copper, iron, and manganese.

A report from the UK Soil Laboratory in the Division of Regulatory Services will be sent
electronically to our office. The report will contain the results of the analyses and information from the sample submission form. The report, along with recommendations, will be sent to the grower who submitted the sample.

You may pick up a sample bottom from our office prior to collecting the sample. If you choose to use your own bottle, the container must be clean and free of any contamination. Samples should be delivered to our office as soon as possible. If samples must be held, store them in a refrigerator but do not freeze.

For source water samples:
Open the tap and allow it to run for five minutes prior to sampling. Place opened bottle under the stream until it is full. Pour out enough to leave ½ inch of air space. Replace and tighten the cap. If you are submitting more than one sample, mark each sample with an owner ID. 

For nutrient solution samples:
Float Beds: Submerge capped bottle to a depth of 3 inches, then open the bottle and allow it to fill. Pour out enough to leave ½ inch of air space. Replace and tighten the cap. If you are submitting more than one sample, mark each sample with an owner ID.
Overhead or low-pressure systems: Sample as described above for source water at the point far enough below the fertilizer injector to allow for complete mixing.

Water Source and Nutrient Solution Testing Form

Information on Soybean Cyst Nematode, Sampling, Management and more can be found on the UK Plant Pathology Website here.

• Use a soil probe to collect soil 6 to 8 inches deep from at least 20 locations within the sampling area (i.e. 20 sub-samples).
• Follow a “zig-zag” pattern when sampling.
• If you are sampling a field that has most recently been in soybean, collect the soil cores from the soybean root zone area.
• Once the sub-samples have been collected, mix the contents in a bucket and immediately place at least one pint in a soil testing sample bag or in a double-plastic bag and then seal the bag.
• Mark the field name / sample number on the bag.
• Protect the sample from extreme heat. If not sending for analysis immediately, refrigerate sample until sending for analysis. Do not freeze sample.
• Use the special Kentucky Soybean Board sample submission form for the free soybean cyst nematode samples
• Send samples to: University of Illinois Plant Clinic, S-417 Turner Hall, 1102 S. Goodwin Ave., Urbana, IL 61801. Tel: 217-333-0519.

Kentucky Soybean Cyst Nematode Form

Soil should be sampled when the corn is about 6 inches high with between 2 and 4 leaf collars showing (V2-V4). Samples should not be taken later since time is required for the sample to be tested by the lab for sidedressing to occur no later than the V6 stage. Samples may be taken somewhat earlier when corn has 1 leaf collar (V1) if early sidedressing is anticipated. Take soil cores to a 12-inch depth. This is deeper than “routine” soil samples which are taken from 4 to 6 inches deep. The deeper depth is required because nitrate is a soluble nutrient that moves deeper into the soil profile. If the soil probe tip is not long enough to collect a 12-inch core, you will have to probe the soil twice at each point in order to collect the 12-inch sample. Randomly walk through the field collecting about 20 soil cores. Minimize the field area being sampled to about 10 to 20 acres. Because of the variability of soil N availability and the economic importance of N nutrition to corn, it is not wise to collect a sample representing a large area.

It is critical to dry the sample before sending it to a laboratory. The soil needs to be dried because N can undergo biological transformations in a moist sample, causing a laboratory result that is not indicative of field soil conditions. Thoroughly mix each 20-core composite sample from the 10 to 20-acre field. Keep about a pint of the soil and completely air-dry the soil immediately after sampling. To dry the sample quickly, place the soil on a paper plate in front of a gently blowing fan. Do not place the sample in a plastic bag. The soil test laboratory may not perform a PSNT on samples received moist because of the uncertainty in the results.

The PSNT can be used on fields where manure or fertilizers were broadcast applied before planting. The PSNT is not recommended in fields with banded/injected N applications because it is difficult to properly sample such fields and adequately predict N availability.

Send the sample to a laboratory that will perform the PSNT test. The University of Kentucky soil test laboratory at Princeton can perform this test. Submit the sample to a local county extension office and they will send the sample to the laboratory for testing.

PSNT Sample Form