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Improvement of Techniques for Determining Populations of Macroposthonia xenoplax in Dry Soil. Ernest G. Lawrence, Graduate Assistant, Department of Plant Pathology and Physiology, Clemson University, Clemson, SC 29631; Eldon I. Zehr, associate professor, Department of Plant Pathology and Physiology, Clemson University, Clemson, SC 29631. Phytopathology 68:1102-1105. Accepted for publication 31 January 1978. Copyright © 1978 The American Phytopathological Society, 3340 Pilot Knob Road, St. Paul, MN 55121. All rights reserved.. DOI: 10.1094/Phyto-68-1102.

Quantitative assays of soil samples from areas known to be heavily infested with Macroposthonia xenoplax consistently have indicated very low populations in samples that were collected after prolonged dry weather. Modifications of Jenkins’ centrifugal-flotation procedure were tested to improve extraction of this nematode from dry field soil. Mixing dry samples from the field in water with a Waring Blendor just prior to extraction, or increase in the sucrose concentration in the flotation procedure, increased the numbers extracted. Best results were obtained, however, when the soil was moistened to 16-24% (v/w) 1-7 days before the routine procedure was done.