Facial tissues, a small mesh screen, and a small dish are all that’s needed to perform a quick nematode soil analysis.
A quick and easy extraction test can be conducted in your kitchen to learn if your soils and or plant roots harbor nematodes, says Dr. Ekaterini Riga, Washington State University nematologist.
The test is not sophisticated and will not take the place of sending soil samples to a laboratory for nematode analysis, she stressed, but it could serve to confirm suspicions that nematodes are present in your soil. Though the dagger nematode can be seen by the bare eye, a magnifying glass or microscope will be needed to see smaller nematodes.
Riga said that standard nematode soil collection methods should be followed when collecting soil for the kitchen test. Generally, the best time to sample for nematodes—if you don’t know what species are present—is in the spring when soil temperatures have reached 50°F and there is moisture in the soil.
Do not let the sample get hot or dry, and try to run the extraction test soon after you collect your soil sample, she advised. Samples can be placed in the refrigerator for a few days in a plastic bag or kept in paper bags in a cooler for a short time, but it is important that the sample not dry out.
Riga noted that the extraction test works only with live nematodes. The nematodes follow gravity and crawl into the water.
1. Collect soil from around the roots.
2. Wrap a small handful of soil in two layers of facial tissue.
3. Place the wrapped soil in a small dish on top of a fine mesh or screen. Add water so that the mesh is slightly covered with water and the soil contacts the water.
4. Let it sit for five to seven days, allowing the nematodes to crawl out of the soil. Make sure the sample stays in contact with the water—don’t let the dish become dry. Covering the dish with plastic wrap or foil will help prevent drying.
5. Remove the bundled soil from the dish and observe the water using a binocular dissecting microscope. You may be able to see nematodes with a magnifying glass. Dagger nematodes are large enough to see with the bare eye.