|
S.
Sardanelli and F. Ellison
Nematology Series, NDRF Fact Sheet No.1 Revised September 2005 |
Diagnosing nematode damage is a difficult task because nematode feeding often resembles many other types of plant stress. Virtually all soil contains nematodes (microscopic worms), although all forms are not plant-parasites. Also, in many cases those that are plant-parasitic occur in populations too small to cause serious plant injury. Since nematodes are invisible to the naked eye in the soil or plant, a nematode assay must be performed in order to determine if nematodes are present. Once the nematodes are extracted, species and populations can be determined.
A Sample Information Form is required with EACH sample submitted. Forms may be obtained from your County Extension Office, or this laboratory.
A nematode assay is only as good as the representative sample that you provide. Therefore, it is important to adhere to the following procedures:
Return to Nematology Homepage
Return to Nematology Links
Time of Sampling
Nematode populations are generally highest in the fall. Sampling at in
this time provides the most reliable information in predicting the effect
of nematode development on crop response.
· Samples can be taken anytime the soil is moist and in good working
condition.
· During the GROWING SEASON, samples may be taken whenever decline
of plant growth is evident.
· For comparative purposes, areas showing healthy plant growth
should be sampled as well as the areas in decline.
· ESTABLISHED PERENNIALS may be sampled whenever decline is of
concern.
Sample Material
· ONE PINT of SOIL is required for analysis of each sample submitted.
· ROOT SAMPLES should be submitted along with the soil sample whenever
possible.
· One ounce of FIBROUS root system should yield an adequate sample
for diagnostic purposes.
Handling Samples- for ALL SAMPLE
TYPES collected.
· Place each sample in a plastic bag, seal tightly to keep moist, and
securely attach a sample identification number or symbol OUTSIDE of
the bag.
· A sample information form must accompany each sample.
· Keep samples out of direct sunlight to avoid overheating. Samples
may also be damaged by heat if they are kept in the trunk of the car. When
storing samples, avoid extremes or either heat or cold.
· Samples should be sent to the laboratory as soon as possible after
collection.
· If the soil in the area to be sampled is not uniform, such as having heavy clay in one portion and a sandy soil in another portion, take one sample from each soil type.
· For an area 4 acres or less in size, one sample is sufficient. For larger fields, divide area into 4-acre blocks and take a sample of each.
· Sample from the plowed layer of soil (6-8 inches) with a soil sampling tube (1 inch bore), trowel, or shovel.
· Take at least 20 cores of soil in a systematic pattern (see sampling pattern diagrams below) for each area to be sampled and deposit soil in a plastic bag. For row crops, sample within the feeder root zone.
 |
| Suggested systematic sampling (A) for collecting general nematode soil samples and (B) suggested sampling of two center rows (20 to 30 soil cores) for experimental plots. |
 |
| Possible sampling pattern for a one plant plot of perennial plants. |
· Soil should be taken from feeder root zone of plants showing decline. Do not sample directly around dead plants.
Trees and Shrubs:
· Sample at the drip line in the fibrous root zone
· To a depth of 6-8 inches,
· Taking at least 10 cores for a single specimen and at least 15 cores
from a row planting.
Turfgrass:
· Sample at the edge of damaged areas (where healthy grass plants meet
with those in decline).
· The total composite sample should consist of approximately 20 cores
of soil taken to a depth of 4 inches.
· Use a systematic pattern similar to the diagram for cover crops in
collecting the sample.
Root Sampling Procedure
· One ounce of fibrous root system should yield an adequate sample
for diagnostic purposes.
· Collect root portions from several areas around declining plant.
Sample should contain root portions that have some living tissue.
Return to Top
Woody Tissue Sampling Procedure-
for diagnosis of Pine Wilt Disease.
· Samples may be collected any time of year, BUT the most successful
time for collection is in the summer months.
· Sample affected branches, 1-2 inches in diameter, which still retain
the needles.
· Submit at least two sections, 4 inches in length and from two different
branches for each tree in decline.
All pictures are courtesy of Nemapix Jounal of Nematological Images, vol. 1 &2, J.D. Eisenback & Ulrich Zunke, eds.
The University of Maryland is equal opportunity. The University's policies, programs, and activities are in conformance with pertinent Federal and State laws and regulations on nondiscrimination regarding race, color, religion, age, national origin, gender, and disability. Inquiries regarding compliance with Title IV of the Civil Rights Act of 1964, as amended: Title IX of the Educational Amendments: Section 504 of the Rehabilitation Act of 1973: and the Americans with Disability Act of 1990: or related legal requirements should be directed to the Director of Personnel/Human Relations, Office of the Dean, College of Agriculture, Symons Hall, College Park, MD 20742.
For comments and questions regarding this internet site contact ssardane@umd.edu.
