Parasitic Nematodes - Tough on Susceptible Garden Plants

Plant Pathology Infobytes

March 2, 1999

Nematodes could be your vegetable garden's worst enemy. These microscopic worms annually cause production problems for vegetable gardeners across the state. The best way to find if you have a problem with root-knot or other kinds of damaging nematodes is to collect soil samples for analysis.

Although the preferred time for sample collection is at the end of the gardening season, there's still time to collect a sample for nematode analysis before the spring gardening season. Gardeners who haven't sampled for these pesky critters in several seasons should place special emphasis on this part of their vegetable production program.

However, there is a "right way" to collect nematode samples. We suggest sample collection according to the following guidelines.

Soil should be moist at time of collection; however, do not sample gardens where standing water is present.
Use a spade, soil collection probe, or similar sampling device to collect samples. If possible, collect the sample from the center of the old rows, with soil coming from the root zone area.
Collect and place in a gallon sized container at least 20 small samples (about 1/4 to ½ cup each) from 6 to 8 inches deep per 5,000 to 10,000 square feet of gardening area. Ten thousand square feet represents about 1/4 acre. The key point is to collect a sufficient number of these small samples to give a representative picture of the nematode situation across the entire sampling area.
Mix this soil thoroughly and put about one pint in a nematode soil sample bag (available from your County Extension Office) or in a plastic freezer bag and seal.
Mark the sample number on the collection container.
After collection, samples must be cared for properly until sent to the Nematode Analysis Laboratory for processing. The samples should be regarded as perishable and handled accordingly. Keep samples in a cool place and avoid sample exposure to direct sunlight and high temperatures to avoid killing nematodes in the sample, rendering it useless for analysis purposes.
Fill out a Nematode Soil Sample Form (available from your county Extension office) and place in plastic bag or envelope. Do not allow the form to remain in contact with the samples since moisture will destroy the form.
Within a few days of collection, take the samples to your local Extension Office for routing to the Nematode Analysis Laboratory at Mississippi State University.

Expect to receive sample results in approximately two weeks. Nematode control recommendations will be provided if problems are detected through the analysis. Contact your county Extension office if you have questions on the nematode collection procedure or how to set up a nematode control program.

Infobytes newsletter was written by the late Dr. Frank Killebrew, Extension Specialist.