Nematode Losses During Centrifugal Extraction from Two Soil Types

Abstract

Estimates of losses at selected stages of a centrifugation procedure were obtained for nematodes infesting Rockdale fine sandy loam and Perrine marl soils in southern Florida. The steps investigated ranged from concentrating a sieved subsample before centrifugation to collection of nematodes following a final centrifugation in a sugar solution. Losses in supernatant water following the first centrifugation (in water) were relatively low ( 5%), except for Helicotylenchus dihystera from Rockdale soil (33.6%) and Meloidogyne incognita juveniles from marl soil (22.2%). For most nematodes, greatest losses occurred in the pellet following centrifugation in sugar solution, ranging from 7.38-29.87% on Rockdale soil and from 2.79-15.50% on marl soil, depending on species. Losses in sieving nematodes suspended in sugar solutions were low (6.00%). Estimates of maximum extraction efficiency over all centrifugation steps were: 85.8% for Criconemella onoensis, 81.6% for Rotylenchulus reniformis, 6